AndroidTutorial from K.Navin

Migrating to Android Studio from Eclipse

2015-07-25T04:52:00.003-07:00

Migrating to Android Studio from Eclipse

Android Studio is the official IDE for Android application development, based on IntelliJ IDEA. On top of the capabilities you expect from IntelliJ, Android Studio offers:

Flexible Gradle-based build system
Build variants and multiple apk file generation
Code templates to help you build common app features
Rich layout editor with support for drag and drop theme editing
lint tools to catch performance, usability, version compatibility, and other problems
ProGuard and app-signing capabilities
Built-in support for Google Cloud Platform, making it easy to integrate Google Cloud Messaging and App Engine

Property name	Property value
Project name	SRM_QRScanner
Package name	in.ac.srmuniv.qrscanner
Activity name	SRM_ScannerActivity
Layout xml name	scanner

SRM_QRScanner Application from this blog

Creating a project from Android Studio 1.2.2

1.Create a new project File->New ->New Project

2.Select minimum SDK tells you how much your application is going to be backward compatible. app support library will be added to your project so that new features added in latest versions of Android will be made usable in backward versions too.

3.Select Blank Activity and click next

4.Name the Activity java source file and layout XML file

5.Project is created with automatic Gradle build .Rendering problem is sorted out by selecting an AppTheme.

6 Select App Theme according to your App requirement.Here we have selected Holo Light Theme in which Holo.Light .DarkActionBar theme style is selected your selection can be seen in styles.xml

7.Now your application is ready for development.With this default run through of the wizard we have created an app with one screen (Activity) with "Hello world" label in left corner.If you run the application you are already provided with one default emulator the application will launch in the emulator with the same screen you see in the layout editor.

Creating project/library from existing Eclipse project in to Android Studio.

8.Select File->New->Import Project to import project developed in eclipse IDE

9.Select the eclipse project/ from eclipse workspace

10 Click Next.In general the project will be stored in Android Studio Projects folder but you can also change the location.

11.Leave with the default selections and click Finish.

12.The Project will be Re build from Gradle build system

13.Import summary will show you any issues such as target platform not found if the target platform (SDK version) is not available in your system it will ask you to download.

14.Here build.gradle file in app folder needs to be modified to available SDK versions we have downloaded in our system.I our case we have API level 22 but not 21.Hence change to 22 as Shown in Fig 18.

15.These steps are required only if the imported project is an Library project.Rename the app folder to another name by refactoring in our case we have renamed it as library.

16.Here we have named it as library.Running the gradle will change entry in settings.gradle file as shown below.

17.The app folder getting changed to library.Also see the change in settings.gradle file

18.Here we show you the changed SDK version in build.gradle file.The defaultConfig entry will not contain applicationID.if it is library project

Importing library project/module to Android Studio project
19.Select New->Import Module to import our library project.

20.Select the library project which has been already build.

21.You can see when the library project android is selected. it automatically selects the module folder.Since we have renamed the folder to library from app there no conflict with our SRM_QRScanner project app folder.

22.Here library module is added to the SRM_QRScanner project.

23.Select File-> Project Structure menu from File

24.Select app =>select tab Dependencies=>Select include -> click '+' button =>Select Module dependency.You will get the library module select it.

25.On selection of library module entry is updated in build.gradle.

26.Add the following lines in appropriate places in AndroidManifest.xml file to eradicate the error for resolving mismatching theme of imported library app.Then finally Sync Gradle to build .

Android Navigation Drawer,Fragments Tutorial

2014-05-16T07:36:00.003-07:00

Android Navigation Drawer,Fragments Tutorial

Navigation Drawer

Navigation Drawer is a recent popular Android UI design for many Apps like Facebook , Google plus , ,you tube, amazon kindle gmail etc.The navigation drawer (Sliding Menu ) is a list “ListView” of options on the left edge of the screen.is a panel that displays the app’s main navigation options on the left edge of the screen. It is hidden most of the time, but is revealed when the user swipes a finger from the left edge of the screen or, while at the top level of the app, the user touches the app icon in the action bar.

For example, the following layout uses a DrawerLayout with two child views: a FrameLayout to contain the main content (populated by a Fragment at runtime), and a ListView for the navigation drawer.
Fragment
A Fragment represents a behavior or a portion of user interface in an Activity.A Fragment must always be embedded in an activity and you can combine multiple fragments in a single activity to build a multi-pane UI and reuse a fragment in multiple activities.
Fragments LifeCycle

Figure1 Shows Fragment Life cycle.

A fragment's lifecycle is directly affected by the host activity's lifecycle. For example, when the activity is paused, so are all fragments in it, and when the activity is destroyed, so are all fragments. However, while an activity is running (it is in the resumed lifecycle state), you can manipulate each fragment independently, such as add or remove them.
Dynamic Fragments

There are two ways you can add a fragment to the activity layout:

Declare the fragment inside the activity's layout file.(Static Fragments)
Programmatically add the fragment to an existing ViewGroup.

To make fragment transactions in your activity (such as add, remove, or replace a fragment), you must use APIs from FragmentTransaction. You can get an instance of FragmentTransaction from your Activity like this:

FragmentManager fragmentManager = getFragmentManager()

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

You can then add a fragment using the add() method, specifying the fragment to add and the view in which to insert it. For example:

ExampleFragment fragment = new ExampleFragment();

fragmentTransaction.add(R.id.fragment_container, fragment);

fragmentTransaction.commit();

The first argument passed to add() is the ViewGroup in which the fragment should be placed, specified by resource ID, and the second parameter is the fragment to add.

Once you've made your changes with FragmentTransaction, you must call commit() for the changes to take effect.

The Demonstrative project uses Sliding menu (Navigation Drawer) to select Fragments to send messages through SMS or EMail.A common Message Fragment passes typed message available for both SMS and EMail fragment .Demonstrates Fragment communication and Dynamic replacement of Fragments.
1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_NavigationDrawerTutorial
Package name	in.ac.srmuniv.navigationdrawertutorial
Activity name	MainActivity
Layout xml name	activity_main

2.Copy the code in SubjectMessage.java. interface.

package in.ac.srmuniv.navigationdrawertutorial.javacomponents;

public interface SubjectMessage {

void setMessage(String msg, int frag);

String getMessage();

}

3.Copy the code to the file activity_main.xml in res/layout folder.

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/drawer_layout"

android:layout_width="match_parent"

android:layout_height="match_parent" >

<FrameLayout

android:id="@+id/frame_container"

android:layout_width="match_parent"

android:layout_height="match_parent" />

<ListView

android:id="@+id/slider_list"

android:layout_width="240dp"

android:layout_height="match_parent"

android:layout_gravity="start"

android:background="#ffffff"

android:choiceMode="singleChoice"

android:divider="@android:color/black"

android:dividerHeight="0dp" />

</android.support.v4.widget.DrawerLayout>

4.Copy the code to the file strings.xml in res/values folder

<?xml version="1.0" encoding="utf-8"?>

<string name="app_name">SRM_NavigationDrawerTutorial</string>

<string name="action_settings">Settings</string>

<string name="hello_world">Hello world!</string>

<string name="imgdesc">imgdesc</string>

<string-array name="titles">

<item>Message</item>

</string-array>

<item>@drawable/message</item>

<item>@drawable/sms</item>

<item>@drawable/email</item>

</array>

</resources>

5.Copy the code in MainActivity.java. Activity.

package in.ac.srmuniv.navigationdrawertutorial.androidcomponents;

import in.ac.srmuniv.navigationdrawertutorial.androidcomponents.R;

import in.ac.srmuniv.navigationdrawertutorial.javacomponents.RowItem;

import in.ac.srmuniv.navigationdrawertutorial.javacomponents.SubjectMessage;

import java.util.ArrayList;

import java.util.List;

import android.annotation.SuppressLint;

import android.annotation.TargetApi;

import android.app.Fragment;

import android.app.FragmentManager;

import android.content.res.Configuration;

import android.content.res.TypedArray;

import android.os.Build;

import android.os.Bundle;

import android.support.v4.app.ActionBarDrawerToggle;

import android.support.v4.app.FragmentActivity;

import android.support.v4.widget.DrawerLayout;

import android.util.Log;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.AdapterView;

import android.widget.ListView;

@TargetApi(Build.VERSION_CODES.HONEYCOMB)

public class MainActivity extends FragmentActivity implements SubjectMessage {

String[] menutitles;

TypedArray menuIcons;

// nav drawer title

private CharSequence mDrawerTitle;

private CharSequence mTitle;

private DrawerLayout mDrawerLayout;

private ListView mDrawerList;

private ActionBarDrawerToggle mDrawerToggle;

private List<RowItem> rowItems;

private CustomAdapter adapter;

private String commMsg = "";

@SuppressLint("NewApi")

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mTitle = mDrawerTitle = getTitle();

menutitles = getResources().getStringArray(R.array.titles);

menuIcons = getResources().obtainTypedArray(R.array.icons);

mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);

mDrawerList = (ListView) findViewById(R.id.slider_list);

rowItems = new ArrayList<RowItem>();

for (int i = 0; i < menutitles.length; i++) {

RowItem items = new RowItem(menutitles[i], menuIcons.getResourceId(

i, -1));

rowItems.add(items);

}

menuIcons.recycle();

adapter = new CustomAdapter(getApplicationContext(), rowItems);

mDrawerList.setAdapter(adapter);

mDrawerList.setOnItemClickListener(new SlideitemListener());

// enabling action bar app icon and behaving it as toggle button

getActionBar().setDisplayHomeAsUpEnabled(true);

getActionBar().setHomeButtonEnabled(true);

mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,

R.drawable.ic_drawer, R.string.app_name, R.string.app_name) {

public void onDrawerClosed(View view) {

getActionBar().setTitle(mTitle);

// calling onPrepareOptionsMenu() to show action bar icons

invalidateOptionsMenu();

}

public void onDrawerOpened(View drawerView) {

getActionBar().setTitle(mDrawerTitle);

// calling onPrepareOptionsMenu() to hide action bar icons

invalidateOptionsMenu();

}

};

mDrawerLayout.setDrawerListener(mDrawerToggle);

if (savedInstanceState == null) {

// on first time display view for first nav item

updateDisplay(0);

}

class SlideitemListener implements ListView.OnItemClickListener {

@Override

public void onItemClick(AdapterView<?> parent, View view, int position,

long id) {

updateDisplay(position);

}

@TargetApi(Build.VERSION_CODES.HONEYCOMB)

private void updateDisplay(int position) {

Fragment fragment = null;

switch (position) {

case 0:

fragment = new Message_Fragment();

break;

case 1:

fragment = new SMS_Fragment();

break;

case 2:

fragment = new EMail_Fragment();

break;

default:

break;

}

if (fragment != null) {

FragmentManager fragmentManager = getFragmentManager();

fragmentManager.beginTransaction()

.replace(R.id.frame_container, fragment).commit();

// update selected item and title, then close the drawer

setTitle(menutitles[position]);

mDrawerLayout.closeDrawer(mDrawerList);

} else {

// error in creating fragment

Log.e("MainActivity", "Error in creating fragment");

}

@Override

public void setTitle(CharSequence title) {

mTitle = title;

getActionBar().setTitle(mTitle);

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

getMenuInflater().inflate(R.menu.main, menu);

return true;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// toggle nav drawer on selecting action bar app icon/title

if (mDrawerToggle.onOptionsItemSelected(item)) {

return true;

}

// Handle action bar actions click

switch (item.getItemId()) {

case R.id.action_settings:

return true;

default:

return super.onOptionsItemSelected(item);

}

/***

* Called when invalidateOptionsMenu() is triggered

@Override

public boolean onPrepareOptionsMenu(Menu menu) {

// if nav drawer is opened, hide the action items

boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);

menu.findItem(R.id.action_settings).setVisible(!drawerOpen);

return super.onPrepareOptionsMenu(menu);

}

/**

* When using the ActionBarDrawerToggle, you must call it during

* onPostCreate() and onConfigurationChanged()...

@Override

protected void onPostCreate(Bundle savedInstanceState) {

super.onPostCreate(savedInstanceState);

// Sync the toggle state after onRestoreInstanceState has occurred.

mDrawerToggle.syncState();

}

@Override

public void onConfigurationChanged(Configuration newConfig) {

super.onConfigurationChanged(newConfig);

// Pass any configuration change to the drawer toggles

mDrawerToggle.onConfigurationChanged(newConfig);

}

@Override

public void setMessage(String str, int frag) {

commMsg = str;

Log.d("MainActivity", commMsg);

Log.d("MainActivity", Integer.valueOf(frag).toString());

switch (frag) {

case 1:

SMS_Fragment sms = (SMS_Fragment) getFragmentManager()

.findFragmentById(R.id.sms_fragmentlay);

if (sms == null) {

System.out.println("Dual fragment - 1");

sms = new SMS_Fragment();

sms.getSMSMessage(commMsg);

// We are in dual fragment (Tablet and so on)

FragmentManager fm = getFragmentManager();

android.app.FragmentTransaction ft = fm.beginTransaction();

ft.replace(R.id.frame_container, sms);

ft.commit();

}

else {

Log.d("SwA", "Dual Fragment update");

// sms.getEMailSubject(commMsg);

}

break;

case 2:

EMail_Fragment email = (EMail_Fragment) getFragmentManager()

.findFragmentById(R.id.email_fragmentlay);

if (email == null) {

System.out.println("Dual fragment - 1");

email = new EMail_Fragment();

email.getEMailMessage(commMsg);

// We are in dual fragment (Tablet and so on)

FragmentManager fm = getFragmentManager();

android.app.FragmentTransaction ft = fm.beginTransaction();

ft.replace(R.id.frame_container, email);

ft.commit();

}

else {

Log.d("SwA", "Dual Fragment update");

// sms.getEMailSubject(commMsg);

}

public String getMessage() {

Log.d("MainActivity", commMsg);

return commMsg;

}

6.Copy the code to the file drawerlist_item.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="48dp"

android:padding="5dp" >

<ImageView

android:id="@+id/icon"

android:layout_width="50dp"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_centerVertical="true"

android:layout_marginLeft="12dp"

android:layout_marginRight="12dp"

android:contentDescription="@string/imgdesc" />

<TextView

android:id="@+id/title"

android:layout_width="wrap_content"

android:layout_height="match_parent"

android:layout_marginTop="10dp"

android:layout_toRightOf="@id/icon"

android:gravity="center_vertical"

android:textColor="#000000"

android:textSize="20sp" />

</RelativeLayout>

7.Copy the code in CustomAdapter.java.

package in.ac.srmuniv.navigationdrawertutorial.androidcomponents;

import in.ac.srmuniv.navigationdrawertutorial.androidcomponents.R;

import in.ac.srmuniv.navigationdrawertutorial.javacomponents.RowItem;

import java.util.List;

import android.app.Activity;

import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.ImageView;

import android.widget.TextView;

public class CustomAdapter extends BaseAdapter {

Context context;

List<RowItem> rowItem;

CustomAdapter(Context context, List<RowItem> rowItem) {

this.context = context;

this.rowItem = rowItem;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

if (convertView == null) {

LayoutInflater mInflater = (LayoutInflater) context

.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

convertView = mInflater.inflate(R.layout.drawerlist_item, null);

}

ImageView imgIcon = (ImageView) convertView.findViewById(R.id.icon);

TextView txtTitle = (TextView) convertView.findViewById(R.id.title);

RowItem row_pos = rowItem.get(position);

// setting the image resource and title

imgIcon.setImageResource(row_pos.getIcon());

txtTitle.setText(row_pos.getTitle());

return convertView;

}

@Override

public int getCount() {

return rowItem.size();

}

@Override

public Object getItem(int position) {

return rowItem.get(position);

}

@Override

public long getItemId(int position) {

return rowItem.indexOf(getItem(position));

}

8.Copy the code in RowItem.java.

package in.ac.srmuniv.navigationdrawertutorial.javacomponents;

public class RowItem {

private String title;

private int icon;

public RowItem(String title, int icon) {

this.title = title;

this.icon = icon;

}

public String getTitle() {

return title;

}

public void setTitle(String title) {

this.title = title;

}

public int getIcon() {

return icon;

}

public void setIcon(int icon) {

this.icon = icon;

}

9.Copy the code to the file message.xml in res/layout folder.For Message_Fragment

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/message_fragmentlay"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical" >

<TextView

android:id="@+id/textView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:text="MESSAGE"

android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText

android:id="@+id/message"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_weight="0.05"

android:ems="10"

android:inputType="textMultiLine" >

</EditText>

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content" >

<Button

android:id="@+id/smsbutton"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="SMS" />

<Button

android:id="@+id/emailbutton"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="E-Mail" />

</LinearLayout>

10.Copy the code in Message_Fragment.java. Fragment.

package in.ac.srmuniv.navigationdrawertutorial.androidcomponents;

import in.ac.srmuniv.navigationdrawertutorial.androidcomponents.R;

import in.ac.srmuniv.navigationdrawertutorial.javacomponents.SubjectMessage;

import android.annotation.SuppressLint;

import android.app.Activity;

import android.app.Fragment;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.Button;

import android.widget.EditText;

import android.view.View.OnClickListener;

@SuppressLint("NewApi")

public class Message_Fragment extends Fragment {

Button smsButton;

Button emailButton;

EditText messageEditText;

SubjectMessage messageInterface;

@Override

public void onAttach(Activity activity) {

// We verify that our activity implements the listener

if (!(activity instanceof SubjectMessage))

throw new ClassCastException();

else

messageInterface = (SubjectMessage) getActivity();

super.onAttach(activity);

}

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

View rootView = inflater.inflate(R.layout.message_fragment, container,

false);

smsButton = (Button) rootView.findViewById(R.id.smsbutton);

emailButton = (Button) rootView.findViewById(R.id.emailbutton);

messageEditText = (EditText) rootView.findViewById(R.id.message);

return rootView;

}

@Override

public void onActivityCreated(Bundle savedInstanceState) {

smsButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

messageInterface.setMessage(messageEditText.getText()

.toString(), 1);

}

});

emailButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

messageInterface.setMessage(messageEditText.getText()

.toString(), 2);

}

});

super.onActivityCreated(savedInstanceState);

}

11.Copy the code to the file sms_fragment.xml in res/layout folder.For SMS_Fragment

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/sms_fragmentlay"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<TextView

android:id="@+id/textViewPhoneNo"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Enter Phone Number : "

android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText

android:id="@+id/editTextPhoneNo"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:phoneNumber="true" >

</EditText>

<TextView

android:id="@+id/textViewSMS"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Enter SMS Message : "

android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText

android:id="@+id/editTextSMS"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:gravity="top"

android:inputType="textMultiLine"

android:lines="5" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_gravity="center" >

<Button

android:id="@+id/sendsmsbutton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Send" />

<Button

android:id="@+id/clearsms"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Clear" />

</LinearLayout>

12.Copy the code in SMS_Fragment.java. Fragment.

package in.ac.srmuniv.navigationdrawertutorial.androidcomponents;

import in.ac.srmuniv.navigationdrawertutorial.androidcomponents.R;

import in.ac.srmuniv.navigationdrawertutorial.javacomponents.SubjectMessage;

import android.annotation.SuppressLint;

import android.app.Activity;

import android.app.Fragment;

import android.content.Intent;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

import android.view.View.OnClickListener;

@SuppressLint("NewApi")

public class SMS_Fragment extends Fragment {

Button sendButton;

Button clearButton;

EditText textPhoneNo;

EditText textSMS;

String message = null;

@Override

public void onAttach(Activity activity) {

if (!(activity instanceof SubjectMessage))

throw new ClassCastException();

message = ((SubjectMessage) getActivity()).getMessage();

super.onAttach(activity);

}

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

View rootView = inflater.inflate(R.layout.sms_fragment, container,

false);

sendButton = (Button) rootView.findViewById(R.id.sendsmsbutton);

clearButton = (Button) rootView.findViewById(R.id.clearsms);

textPhoneNo = (EditText) rootView.findViewById(R.id.editTextPhoneNo);

textSMS = (EditText) rootView.findViewById(R.id.editTextSMS);

return rootView;

}

@Override

public void onActivityCreated(Bundle savedInstanceState) {

textSMS.setText(message);

sendButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Intent smsVIntent = new Intent(Intent.ACTION_VIEW);

// prompts only sms-mms clients

smsVIntent.setType("vnd.android-dir/mms-sms");

// extra fields for number and message respectively

smsVIntent

.putExtra("address", textPhoneNo.getText().toString());

smsVIntent.putExtra("sms_body", textSMS.getText().toString());

try {

startActivity(smsVIntent);

} catch (Exception ex) {

Toast.makeText(getActivity().getApplicationContext(),

"Your sms has failed...", Toast.LENGTH_LONG).show();

ex.printStackTrace();

}

});

clearButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

textSMS.setText("");

}

});

super.onActivityCreated(savedInstanceState);

}

void getSMSMessage(String str) {

message = str;

}

13.Copy the code to the file email_fragment.xml in res/layout folder.For EMail_Fragment

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/email_fragmentlay"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<TextView

android:id="@+id/textViewPhoneNo"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="To : "

android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText

android:id="@+id/editTextTo"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:inputType="textEmailAddress" >

</EditText>

<TextView

android:id="@+id/textViewSubject"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Subject : "

android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText

android:id="@+id/editTextSubject"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

</EditText>

<TextView

android:id="@+id/textViewMessage"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Message : "

android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText

android:id="@+id/editTextMessage"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:gravity="top"

android:inputType="textMultiLine"

android:lines="5" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_gravity="center"

<Button

android:id="@+id/sendemailButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Send"

android:layout_weight="1" />

<Button

android:id="@+id/clearmsg"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Clear"

android:layout_weight="1" />

</LinearLayout>

14.Copy the code in EMail_Fragment.java. Fragment.

package in.ac.srmuniv.navigationdrawertutorial.androidcomponents;

import in.ac.srmuniv.navigationdrawertutorial.androidcomponents.R;

import in.ac.srmuniv.navigationdrawertutorial.javacomponents.SubjectMessage;

import android.annotation.SuppressLint;

import android.app.Activity;

import android.app.Fragment;

import android.content.Intent;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.Button;

import android.widget.EditText;

import android.view.View.OnClickListener;

@SuppressLint("NewApi")

public class EMail_Fragment extends Fragment {

Button sendButton;

Button clearButton;

EditText textTo;

EditText textSubject;

EditText textMessage;

String subject = null;

@Override

public void onAttach(Activity activity) {

if (!(activity instanceof SubjectMessage))

throw new ClassCastException();

subject = ((SubjectMessage) getActivity()).getMessage();

super.onAttach(activity);

}

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

View rootView = inflater.inflate(R.layout.email_fragment, container,

false);

sendButton = (Button) rootView.findViewById(R.id.sendemailButton);

clearButton = (Button) rootView.findViewById(R.id.clearmsg);

textTo = (EditText) rootView.findViewById(R.id.editTextTo);

textSubject = (EditText) rootView.findViewById(R.id.editTextSubject);

textMessage = (EditText) rootView.findViewById(R.id.editTextMessage);

return rootView;

}

@Override

public void onActivityCreated(Bundle savedInstanceState) {

textMessage.setText(subject);

sendButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

String to = textTo.getText().toString();

String subject = textSubject.getText().toString();

String message = textMessage.getText().toString();

Intent email = new Intent(Intent.ACTION_SEND);

email.putExtra(Intent.EXTRA_EMAIL, new String[] { to });

// email.putExtra(Intent.EXTRA_CC, new String[]{ to});

// email.putExtra(Intent.EXTRA_BCC, new String[]{to});

email.putExtra(Intent.EXTRA_SUBJECT, subject);

email.putExtra(Intent.EXTRA_TEXT, message);

// need this to prompts email client only

email.setType("message/rfc822");

startActivity(Intent.createChooser(email,

"Choose an Email client :"));

}

});

clearButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

textMessage.setText("");

}

});

super.onActivityCreated(savedInstanceState);

}

void getEMailMessage(String str) {

subject = str;

}

15.Copy the code to the file menu.xml in res/menu folder.

<item

android:id="@+id/action_settings"

android:orderInCategory="100"

android:showAsAction="never"

android:title="@string/action_settings"/>

</menu>

16.No need to modify Androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.navigationdrawertutorial.androidcomponents"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="14"

android:targetSdkVersion="18" />

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name="in.ac.srmuniv.navigationdrawertutorial.MainActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

16.Run the application in the emulator.

Figure 2 Shows Message_Fragment in view when App is loaded Figure 3 Shows when user swipe or tap the Action bar icon Navigation Drawer is available

Figure 4 Shows message being typed in Message_Fragment.Figure 5 Shows when SMS button being clicked in Message_Fragment replaces it with SMS_Fragment Dynamically with message passed to it through the parent Activity.

Figure 6 Shows Message Application called through Intent when send button is clicked.Figure 7 Shows Message_Fragment replaced dynamically by EMail_Fragment with message passed along through parent Activity.

Figure 8 Shows EMail Application being called through Intent when send button clicked Figure 9 Shows project anatomy.
CODE EXPLANATION
In our project DrawerLayout is the main container layout in activity_main.xml is the inflated view for the MainActivity.Add two views, one for the main view “when the drawer is hidden” and one for the drawer.We are dynamically going to insert Fragments.The main content view (FrameLayout) must be the first child in the DrawerLayout because the XML order implies z-ordering and the drawer must be on top of the content.

The list item layout is a imageview and TextView(for Message,SMS,Email), but we can do styling such as padding, background color, text color and text size.res/layout/drawerlist_item_item.xml.
We need to define string array for the drawer list.Get the list “array” of items to be added to the drawer list from res/values/strings.xml mDrawerList.setAdapter(adapter); mDrawerList.setOnItemClickListener(new SlideitemListener());
Get the reference to the ListView Call ListView.setAdapter(ArrayAdapter).

class SlideitemListener implements ListView.OnItemClickListener {

@Override

public void onItemClick(AdapterView<?> parent, View view, int position,

long id) {

updateDisplay(position);

}

}
4.The inner class called SlideitemListener , Inside the MainActivity class which override onItemClick method inside this method call updateDisplay() method by passing position as a parameter to it and then inside updateDisplay by knowing the position clicked ,we are replacing the current fragment with the respective fragment associated with the items of listview .you can find the updateDisplay method inside them MainActivity class .

FragmentManager fragmentManager = getFragmentManager();

fragmentManager.beginTransaction() .replace(R.id.frame_container, fragment).commit();
5.Dynamic replacement of one fragment with other is shown with above code in updateDisplay() method.Remember you are replacing the the containerID not the fragment ID.the fragment object is the selected list item from Sliding Menu.
Action Bar Open & Close the Drawer With App Icon

Get reference to DrawerLayout define in activity_main.xml.Declare ActionBarDrawerToggle

// enabling action bar app icon and behaving it as toggle button

getActionBar().setDisplayHomeAsUpEnabled(true);

getActionBar().setHomeButtonEnabled(true);

mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,

R.drawable.ic_drawer, R.string.app_name, R.string.app_name) {

public void onDrawerClosed(View view) {

getActionBar().setTitle(mTitle);

// calling onPrepareOptionsMenu() to show action bar icons

invalidateOptionsMenu();

}

public void onDrawerOpened(View drawerView) {

getActionBar().setTitle(mDrawerTitle);

// calling onPrepareOptionsMenu() to hide action bar icons

invalidateOptionsMenu();

}

};

mDrawerLayout.setDrawerListener(mDrawerToggle);

The Listener enables to change Action Bar title,icon etc.it also invalidates option menu
Fragments Life Cycle

onAttach():
EMail_Fragment code snippets

@Override

public void onAttach(Activity activity) {

if (!(activity instanceof SubjectMessage))

throw new ClassCastException();

subject = ((SubjectMessage) getActivity()).getMessage();

super.onAttach(activity);

}

This signifies that the Activity has attached fragment on it and it doesn’t mean that all the views of Activity are created not it means that Activity is fully functional. This is just a point where you can reference the activity.In our app we test the instance of the parent Activity which holds it.Since the fragments could be reused by many activities in an App.We need to get the instance of the activity to do ant message passing.
onCreate():
Just a point which shows that Fragment is in the process of creation and in this method just try to access those values that you have saved on

onSavedInstanceState(Bundle
outState)

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

View rootView = inflater.inflate(R.layout.message_fragment, container,

false);

smsButton = (Button) rootView.findViewById(R.id.smsbutton);

emailButton = (Button) rootView.findViewById(R.id.emailbutton);

messageEditText = (EditText) rootView.findViewById(R.id.message);

return rootView;

}

onCreateView():
Here we inflate the layout or simply create the view and further if you have to do anything that takes reference to Activity don’t do it like creating dialogs,accessing views of Activity etc because,this place doesn’t ensure that hosting Activity is fully functional.Buttons and editText of the message fragments are instantiated.you need to get the rootView to use findViewById().
onActivityCreated():
EMail_Fragment code snippets

textMessage.setText(subject);

sendButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {
// Event handling code
}

This place signifies that our hosting Activity views are created and hosting Activity is functional and this is the right place to do all your Activity related task.Setting the message value passed from Message_Fragment in editText..Event handling code implementation for send button calls in build EMail application for sending Tmail.

onResume():
Here code to do all the actions of the fragment is written
Fragment communication
In our example we have three fragments ,Message_Fragment is a common entry form in which message typed can be passed , when user clicks the Button (SMS or Email) in the fragment 1 (Message_Fragment) the other one (SMS_Fragment (or) EMail_Fragment) is called.So we need to find a way to let these fragments to exchange data.

A fragment is a piece of code that can be re-used inside other activity so we don’t want to bind our fragment to a specific activity to not invalidate our work. In Java if we want to decouple two classes we can use an interface. So this interface solution fits perfectly. On the other hand we don’t want that our fragment exchange information directly because each fragment can rely only on the activity that holds it. So the simplest solution is that the activity implements an interface.

public interface SubjectMessage {

void setMessage(String msg, int frag);

String getMessage();

}

Message_Fragment.java
code snippets
SubjectMessage messageInterface;
......
onAttach() method
messageInterface = (SubjectMessage) getActivity();
......
onClick() method (SMS button)
messageInterface.setMessage(messageEditText.getText()

.toString(), 1);
.....
onClick() method (EMail button)

messageInterface.setMessage(messageEditText.getText()

.toString(), 2);
SMS/Email Fragment code snippets

subject = ((SubjectMessage) getActivity()).getMessage();
The Figure shows that message Fragment tests the instance of the parent activity holding the fragment and calls the method of the activity implemented by interface SubjectMessage.

Android AIDL Remote Services and Upload File from Android Device to Server

2014-05-09T10:27:00.000-07:00

Android AIDL Remote Services and Upload File from Android Device to Server

What is Service
A Service is an application component that can perform long-running operations in the background and does not provide a user interface. Another application component can start a service and it will continue to run in the background even if the user switches to another application. Additionally, a component can bind to a service to interact with it and even perform interprocess communication (IPC). For example, a service might handle network transactions, play music, perform file I/O, or interact with a content provider, all from the background.
Types of service

There are two types of Service 1.Local service 2.Remote service. The local service component can be called only the components of same application,but Remote services can be called and may be shared by other application components.To implement remote service AIDL file which is similar to java interface with file extension .aidl.To bind service running in other process and perform inter process communication (IPC) this is required.
AIDL

AIDL (Android Interface Definition Language) is similar to other IDLs you might have worked with. It allows you to define the programming interface that both the client and service agree upon in order to communicate with each other using interprocess communication (IPC). On Android, one process cannot normally access the memory of another process. So to talk, they need to decompose their objects into primitives that the operating system can understand, and marshall the objects across that boundary for you. The code to do that marshalling is tedious to write, so Android handles it for you with AIDL.

Bound Service

Bound service is "bound" when an application component binds to it by calling bindService(). A bound service offers a client-server interface that allows components to interact with the service, send requests, get results, and even do so across processes with interprocess communication (IPC). A bound service runs only as long as another application component is bound to it. Multiple components can bind to the service at once, but when all of them unbind, the service is destroyed.

The demonstrative project has two applications,one is Remote service application SRM_UploadFileRemoteService which reads a file from SD card,with file name provided by client application SRM_FileUploadClient and uploads it to php webserver.

Use URL http://navinsandroidtutorial.comlu.com/upload/upload.php instead of localhost to upload file from android device.You can view the uploaded file by typing the url in the browser http://navinsandroidtutorial.comlu.com/upload/uploads/file-name

1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_UploadFileRemoteService
Package name	in.ac.srmuniv.remoteservice
Activity name	-
Layout xml name	-

2.Create a file IRemoteFileUpload.aidl file and copy the code given below.

/* The package where the aidl file is located */

package in.ac.srmuniv.remoteservice;

/* The name of the remote service */

interface IRemoteFileUploadService {

/* A simple Method which will return a message string */

String uploadFile(String sourceFileUri);

}

Figure 1 Shows IRemoteFileUpload.aidl file added to source folder.Generated java file for the aidl file is also shown.

3.Create a Service SRM_FileUploadRemoteService.java and copy the code given below .

package in.ac.srmuniv.remoteservice;

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.StrictMode;
import android.util.Log;

public class SRM_FileUploadRemoteService extends Service {
    private static final String SRMUNIV_INTENT_ACTION_BIND_MESSAGE_SERVICE = "srmuniv.intent.action.bindMessageService";
    private final static String LOG_TAG = SRM_FileUploadRemoteService.class
            .getCanonicalName();

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(LOG_TAG, "The SRM_FileUploadRemoteService was created.");
    }

    @Override
    public void onDestroy() {
        Log.d(LOG_TAG, "The SRM_FileUploadRemoteService was destroyed.");
        super.onDestroy();
    }

    @Override
    public IBinder onBind(Intent intent) {
        if (SRMUNIV_INTENT_ACTION_BIND_MESSAGE_SERVICE.equals(intent
                .getAction())) {
            Log.d(LOG_TAG, "The SRM_FileUploadRemoteService was binded.");
            return new UploadFileService();
        }
        return null;
    }

    String response = null;

    String uploadForRemoteService(String sourceFileUri) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        String upLoadServerUri = "http://navinsandroidtutorial.comlu.com/upload/upload.php";
        String fileName = sourceFileUri;
        Log.e("uploadFile", sourceFileUri);
        HttpURLConnection conn = null;
        DataOutputStream dos = null;
        String lineEnd = "\r\n";
        String twoHyphens = "--";
        String boundary = "*****";
        int bytesRead, bytesAvailable, bufferSize;
        byte[] buffer;
        int maxBufferSize = 1 * 1024 * 1024;
        File sourceFile = new File(sourceFileUri);
        if (!sourceFile.isFile()) {
            Log.e("uploadFile", "Source File Does not exist");
            response = "Source File Does not exist";
            return response;
        }
        try { // open a URL connection to the PHP
            FileInputStream fileInputStream = new FileInputStream(sourceFile);
            URL url = new URL(upLoadServerUri);
            conn = (HttpURLConnection) url.openConnection(); // Open a HTTP
            // connection to the URL
            conn.setDoInput(true); // Allow Inputs
            conn.setDoOutput(true); // Allow Outputs
            conn.setUseCaches(false); // Don't use a Cached Copy
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Connection", "Keep-Alive");
            conn.setRequestProperty("ENCTYPE", "multipart/form-data");
            conn.setRequestProperty("Content-Type",
                    "multipart/form-data;boundary=" + boundary);
            conn.setRequestProperty("uploaded_file", fileName);
            dos = new DataOutputStream(conn.getOutputStream());
            dos.writeBytes(twoHyphens + boundary + lineEnd);
            dos.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
                    + fileName + "\"" + lineEnd);
            dos.writeBytes(lineEnd);
            bytesAvailable = fileInputStream.available(); // create a buffer ofmaximum size
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            buffer = new byte[bufferSize];
            // read file and write it into form...
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);
            while (bytesRead > 0) {
                dos.write(buffer, 0, bufferSize);
                bytesAvailable = fileInputStream.available();
                bufferSize = Math.min(bytesAvailable, maxBufferSize);
                bytesRead = fileInputStream.read(buffer, 0, bufferSize);
            }

            // send multipart form data necesssary after file data...
            dos.writeBytes(lineEnd);
            dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

            // Responses from the server (code and message)
            int serverResponseCode = conn.getResponseCode();
            String serverResponseMessage = conn.getResponseMessage();

            Log.i("uploadFile", "HTTP Response is : " + serverResponseMessage
                    + ": " + serverResponseCode);

            if (serverResponseCode == 200)
                response = "File uploaded Sucessfully";
            else
                response = "File not uploaded Sucessfully";

            // close the streams //
            fileInputStream.close();
            dos.flush();
            dos.close();

        } catch (MalformedURLException ex) {
            response = "Url not found";
            ex.printStackTrace();
            Log.e("Upload file to server", "error: " + ex.getMessage(), ex);

        } catch (IOException e) {
            e.printStackTrace();
            response = "error in upload";
            Log.e("Server Exception","Exception : " + e.getMessage(), e);
        }
        return response;
    }

    public class UploadFileService extends IRemoteFileUploadService.Stub {
        @Override
        public String uploadFile(String url) throws RemoteException {
            return uploadForRemoteService(url);
        }
    }

}

4.Modify Androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.remoteservice"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk android:minSdkVersion="3" />

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<application

android:icon="@drawable/icon"

android:label="@string/app_name" >

<intent-filter>

</action>

</intent-filter>

</service>

</application>

</manifest>

5.Run the application in the emulator.
Since no activity is involved there is no output is seen.but you have to run the service.

The source code for upload.php is given below copy it in the folder c:/xampp/htdocs/upload/upload.php
if you are using xampp server

<?php

$target_path1 = "uploads/";

/* Add the original filename to our target path.

Result is "uploads/filename.extension" */

$target_path1 = $target_path1 . basename( $_FILES['uploaded_file']['name']);

if(move_uploaded_file($_FILES['uploaded_file']['tmp_name'], $target_path1)) {

echo "The first file ". basename( $_FILES['uploaded_file']['name']).

" has been uploaded.";

} else{

echo "There was an error uploading the file, please try again!";

echo "filename: " . basename( $_FILES['uploaded_file']['name']);

echo "target_path: " .$target_path1;

}

CODE EXPLANATION

The AIDL file created in src folder would make the Eclipse+AIDL tool will generate a file with the same name, but .java extension .The file is generated in gen folder /gen/in.ac.srmuniv.remoteservice/ IRemoteFileUpload.java file. This is an auto-generated file one should not edit it. It contains a Stub class that will be implemented in our remote service.

public IBinder onBind(Intent intent) {

if (SRMUNIV_INTENT_ACTION_BIND_MESSAGE_SERVICE.equals(intent

.getAction())) {

Log.d(LOG_TAG, "The SRM_FileUploadRemoteService was binded.");

return new UploadFileService();

}

return null;

}

To implement our remote service, we'll return the IBinder from onBind() method in our service class,SRM_FileUploadRemoteService. The IBinder represents the implementation of the remote service. To implement IBinder,

public class UploadFileService extends IRemoteFileUploadService.Stub {

@Override

public String uploadFile(String url) throws RemoteException {

return uploadForRemoteService(url);

}

we subclass IRemoteFileUploadService.Stub class from the auto-generated Java code, and provide implementation for our AIDL-defined methods, in our case uploadFile(String url).

Once we have the service implement the onBind() properly, we are ready to connect to that service from our client.
HttpUrlconnection with necessary header properties set enables to post values to the server.In our app we have a hard coded url "http://10.0.2.2/upload/upload.php".The server side code should written compatible to the app to receive the posted values from app for processing.

1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_FileUploadClient
Package name	in.ac.srmuniv.remoteclient
Activity name	SRM_FileUploadClient
Layout xml name	activity_main

2.Copy with package the IRemoteFileUpload.aidl file to the source folder of the client application

Figure 2 Shows copied IRemoteFileUpload.aidl file to the source folder.Generated java stub file is also shown.

3.Copy the code to the file activity_main.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:layout_marginTop="20dp"

android:orientation="vertical" >

<TableLayout

android:layout_width="match_parent"

android:layout_height="wrap_content" >

<TableRow

android:id="@+id/tableRow1"

android:layout_width="wrap_content"

android:layout_height="wrap_content" >

<TextView

android:id="@+id/textView1"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="ChooseFile"

android:textAppearance="?android:attr/textAppearanceLarge" />

<EditText

android:id="@+id/editText1"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:ems="10" >

</EditText>

</TableRow>

<TableRow

android:id="@+id/tableRow2"

android:layout_width="wrap_content"

android:layout_height="wrap_content" >

<TextView

android:id="@+id/textView2"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Note: Enter file name with if the file is in folder enter relative path eg: srm/resume.txt" />

</TableRow>

<TableRow

android:id="@+id/tableRow3"

android:layout_width="wrap_content"

android:layout_height="wrap_content" >

<Button

android:id="@+id/uploadButton"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Bind" />

<Button

android:id="@+id/disconnectButton"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Disconnct" />

</TableRow>

<TableRow

android:id="@+id/tableRow4"

android:layout_width="wrap_content"

android:layout_height="wrap_content" >

<TextView

android:id="@+id/messageTextView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center"

android:text=""

android:textAppearance="?android:attr/textAppearanceLarge" />

</TableRow>

</TableLayout>

</LinearLayout>

4.Copy the code in SRM_FileUploadClient .java. Activity.

package in.ac.srmuniv.remoteclient;

import in.ac.srmuniv.remoteclient.R;

import in.ac.srmuniv.remoteservice.IRemoteFileUploadService;

import android.app.Activity;

import android.content.ComponentName;

import android.content.Context;

import android.content.Intent;

import android.content.ServiceConnection;

import android.os.Bundle;

import android.os.Environment;

import android.os.Handler;

import android.os.IBinder;

import android.os.RemoteException;

import android.util.Log;

import android.view.Gravity;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

public class SRM_FileUploadClientActivity extends Activity {

protected static final String LOG_TAG = "DisplayClient";

private Button disconnectButton;

private Button uploadButton;

private EditText edittext;

private IRemoteFileUploadService IRservice;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

disconnectButton = (Button) findViewById(R.id.disconnectButton);

uploadButton = (Button) findViewById(R.id.uploadButton);

edittext = (EditText) findViewById(R.id.editText1);

disconnectButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

disconnectService();

}

});

uploadButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Runnable r = new Runnable() {

@Override

public void run() {

uploadFilesServiceCall();

}

};

Handler h = new Handler();

h.post(r);

}

});

}

private ServiceConnection mConnection = new ServiceConnection() {

public void onServiceConnected(ComponentName className, IBinder service) {

IRservice = IRemoteFileUploadService.Stub.asInterface(service);

}

public void onServiceDisconnected(ComponentName className) {

IRservice = null;

}

};

public void connectService() {

if (IRservice == null) {

Intent bindIntent = new Intent(

"srmuniv.intent.action.bindMessageService");

bindIntent.setClassName("in.ac.srmuniv.remoteservice",

"in.ac.srmuniv.remoteservice"

+ ".SRM_FileUploadRemoteService");

bindService(bindIntent, mConnection, Context.BIND_AUTO_CREATE);

Log.d(LOG_TAG,

"The Service will be connected soon (asynchronus call)!");

}

public void disconnectService() {

if (IRservice != null) {

IRservice = null;

unbindService(mConnection);

Log.d(LOG_TAG, "The connection to the service was closed.!");

uploadButton.setText("Bind");

}

public void uploadFilesServiceCall() {

Log.d(LOG_TAG, "Uploading file from the Service.");

if (IRservice == null) { // if the service is null the //connection is not established.

Log.d(LOG_TAG, "The service was not connected -> connecting.");

connectService();

uploadButton.setText("Upload");

} else {

Log.d(LOG_TAG, "The Service is already connected Uploading file.");

try {

String message = IRservice.uploadFile(Environment

.getExternalStorageDirectory().getPath()

+ "/"

+ edittext.getText().toString());

Toast toast = Toast.makeText(getApplicationContext(), message,

Toast.LENGTH_LONG);

toast.setGravity(Gravity.TOP, 25, 400);

toast.show();

} catch (RemoteException e) {

Log.e(LOG_TAG, "An error occured during the service call.");

}

5.No need to ModifyAndroidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.remoteclient"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk android:minSdkVersion="3" />

<application

android:icon="@drawable/icon"

android:label="@string/app_name" >

<activity android:name="in.ac.srmuniv.remoteclient.SRM_FileUploadClientActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

6. Push a File to SD Card

Figure 3 Shows a text file is pushed to SD card in emulator

6.Run the application in the emulator.

Figure 4 Shows clicking to bind the service. Figure 5 Shows file from SD card typed in edit text uploaded to server successfully

Figure 6 Shows uploaded file from android device is available in the server.Type the URL in web browser to view the file content of the uploaded file.

CODE EXPLANATION
Copying the IRemoteFileUpload.aidl file in appropriate package in SRM_FileUploadClient application from SRM_FileUploadRemoteService application generates IRemoteFileupload.java stub file in gen folder.
The following code in SRM_FileUploadClientActivity is for Service Connection object.

private ServiceConnection mConnection = new ServiceConnection() {

public void onServiceConnected(ComponentName className, IBinder service) {

IRservice = IRemoteFileUploadService.Stub.asInterface(service);

}

public void onServiceDisconnected(ComponentName className) {

IRservice = null;

}

};

The client application SRM_FileUploadClient consumes the remote service .We have SRM_FileUploadClientActivity connects to the service. The anonymous ServiceConnection type class implements onServiceConnected() and onServiceDiconnected() methods. These callback methods will get the stub implementation of the remote service upon connection. We need to cast them from stubs to our AIDL service implementation. To do that, we use the following code

IRemoteFileUpload.Stub.asInterface((IBinder)
boundService)

helper method.
The following code in SRM_FileUploadClientActivity is for binding service when button is clicked.

bindService(bindIntent, mConnection, Context.BIND_AUTO_CREATE);

Log.d(LOG_TAG,

"The Service will be connected soon (asynchronous call)!");

When Bind button is clicked bindService() is called which will create the service if it is not created. referenced by bindIntent object it also takes ServiceConnection object as argument which enables communication with service through the IRservice object.
The following code will be called when upload button is clicked.

String message = IRservice.uploadFile(Environment

.getExternalStorageDirectory().getPath()

+ "/"

+ edittext.getText().toString());

When upLoad button is clicked through IRservice object (IRemoteFileUpload remote service object) upLoadFile() method is called.The file name of the file in SD card is typed through EditText and passed as the agument for the remote method call.It is preferable to use third party FileChooser app for selecting files to upload from device.

String uploadForRemoteService(String sourceFileUri) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
the above code is needed other wise networkOnmainThread error will occur.But it is recommended to use AysncTask instead.

Android Alarm Manager Service and Intent service Practical Tutorial

2014-04-19T10:49:00.003-07:00

Android Alarm Manager Service and Intent service Practical Tutorial

Alarm Manager

Cron like service are available in Linux to schedule jobs is available in Android in the form of AlarmManager. AlarmManager allows you to schedule your application to run at a time in the future

Alarms (based on the AlarmManager class) give you a way to perform time-based operations outside the lifetime of your application. For example, you could use an alarm to initiate a long-running operation, such as starting a service once a day to download a weather forecast,stock details to get the trend of the day etc .

Alarms have these characteristics:

They let you fire Intents at set times and/or intervals.
You can use them in conjunction with broadcast receivers to start services and perform other operations.
They operate outside of your application, so you can use them to trigger events or actions even when your app is not running, and even if the device itself is asleep.
They help you to minimize your app's resource requirements. You can schedule operations without relying on timers or continuously running background services.

Choice of Alarm manager for your Application

A repeating alarm is a relatively simple mechanism with limited flexibility. It may not be the best choice for your app, particularly if you need to trigger network operations. A poorly designed alarm can cause battery drain and put a significant load on servers.

A common scenario for triggering an operation outside the lifetime of your app is syncing data with a server. This is a case where you might be tempted to use a repeating alarm. But if you own the server that is hosting your app's data, using Google Cloud Messaging (GCM) in conjunction with sync adapter is a better solution than AlarmManager. A sync adapter gives you all the same scheduling options as AlarmManager, but it offers you significantly more flexibility.

IntentService

The IntentService is used to perform a certain task in the background. Once done, the instance of IntentService terminates itself automatically. An example for its usage would be downloading certain resources from the internet.

The IntentService class offers the onHandleIntent() method which will be asynchronously called by the Android system.
If the service should be communicating back to the activity, it can receive an object of type Messenger via the Intent data it receives from the activity. If the Messenger is bound to a Handler in the activity, the service can send objects of type Message to the activity.
A Messenger is parcelable, which means it can be passed to another process and you can use this object to send Messages to the Handler in the activity.
Messenger also provides the method getBinder() which allows to pass a Messenger to the activity. The activity can therefore send Messages to the service.
This approach works for local services running in their own process.

This Demonstrative App is meant to get updated of messages from a website in form of JSON every 15 seconds .Uses Alarm Manager to trigger repeating alarm to start a Service which downloads message from server at regular intervals.The messages are updated through a form in website manually.
(You can try nawinsandroidtutorial.site90.com/message/Message.php to type message to create message.json file replace local host with the above address)

1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_AlarmService
Package name	in.ac.srmuniv.alarmservice
Activity name	MainActivity
Layout xml name	activity_main

2.Copy the code to the file activity_main.xml in res/layout folder

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:id="@+id/LinearLayout1"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context=".MainActivity" >

<TextView

android:id="@+id/textView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:layout_marginTop="8dp"

android:text="Live Messages:"

android:textAppearance="?android:attr/textAppearanceLarge" />

<TextView

android:id="@+id/textView"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_gravity="fill_horizontal"

android:layout_weight="0.57"

android:textStyle="italic" />

<Button

android:id="@+id/button1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:layout_marginBottom="16dp"

android:text="Stop Update" />

</LinearLayout>

3.Copy the code in MainActivity.java. Activity.

package in.ac.srmuniv.alarmservice;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.Calendar;

import java.util.GregorianCalendar;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import in.ac.srmuniv.alarmservice.R;

import android.app.Activity;

import android.app.AlarmManager;

import android.app.PendingIntent;

import android.content.Intent;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.os.Handler;

import android.os.Message;

import android.os.Messenger;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import android.view.View.OnClickListener;

import android.widget.Toast;

public class MainActivity extends Activity {

private PendingIntent pendingIntent;

GregorianCalendar calendar;

Button b1;

private Handler handler = new Handler() {

public void handleMessage(Message message) {

Object path = message.obj;

if (message.arg1 == RESULT_OK && path != null) {

Toast.makeText(MainActivity.this,

"Downloaded" + path.toString(), Toast.LENGTH_LONG)

.show();

readMessage(path.toString());

} else {

Toast.makeText(MainActivity.this, "Download failed.",

Toast.LENGTH_LONG).show();

}

};

AlarmManager alarmManager;

TextView messageText;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

messageText = (TextView) findViewById(R.id.textView);

b1 = (Button) findViewById(R.id.button1);

readMessage("/storage/sdcard/message.json");

b1.setOnClickListener(new OnClickListener() {

private boolean flag = true;

@Override

public void onClick(View v) {

if (flag) {

flag = false;

b1.setText("Start update");

alarmManager.cancel(pendingIntent);

} else {

flag = true;

b1.setText("Stop update");

alarmManager.setRepeating(AlarmManager.RTC,

calendar.getTimeInMillis(), 15000, pendingIntent);

}

});

calendar = (GregorianCalendar) Calendar.getInstance();

Intent myIntent = new Intent(MainActivity.this, UpdatingService.class);

Messenger messenger = new Messenger(handler);

myIntent.putExtra("MESSENGER", messenger);

myIntent.setData(Uri

.parse("http://10.0.2.2/message/message.json"));// nawinsandroidtutorial.site90.com/message

myIntent.putExtra("urlpath",

"http://10.0.2.2/message/message.json");

pendingIntent = PendingIntent.getService(MainActivity.this, 0,

myIntent, 0);

alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);

alarmManager.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(),

15000, pendingIntent);

} // end onCreate

void readMessage(String path) {

File myFile = new File(path.toString());// Environment.getExternalStorageDirectory().getPath()+"/message.json");

FileInputStream fIn;

try {

fIn = new FileInputStream(myFile);

BufferedReader myReader = new BufferedReader(new InputStreamReader(

fIn));

String aDataRow = "";

String aBuffer = "";

while ((aDataRow = myReader.readLine()) != null) {

aBuffer += aDataRow;

}

myReader.close();

try {

JSONObject jObj = new JSONObject(aBuffer);

aBuffer = jObj.getString("message");

} catch (JSONException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

messageText.setText(aBuffer);

} catch (FileNotFoundException e) {

messageText.setText("No file");

e.printStackTrace();

} catch (IOException e) {

messageText.setText("IO Error");

e.printStackTrace();

}

4.Copy the code in UpdatingService.java. Service.

package in.ac.srmuniv.alarmservice;

import android.app.IntentService;

import android.content.Intent;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.net.URL;

import android.app.Activity;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.os.Message;

import android.os.Messenger;

import android.util.Log;

public class UpdatingService extends IntentService {

String tag = "Nawin";

private int result = Activity.RESULT_CANCELED;

public UpdatingService() {

super("UpdatingService");

}

// Will be called asynchronously be Android

@Override

protected void onHandleIntent(Intent intent) {

Uri data = intent.getData();

String urlPath = intent.getStringExtra("urlpath");

Log.d(tag, urlPath);

String fileName = data.getLastPathSegment();

File output = new File(Environment.getExternalStorageDirectory(),

fileName);

if (output.exists()) {

output.delete();

}

InputStream stream = null;

FileOutputStream fos = null;

try {

URL url = new URL(urlPath);

stream = url.openConnection().getInputStream();

InputStreamReader reader = new InputStreamReader(stream);

Log.d(tag, "connection done");

fos = new FileOutputStream(output.getPath());

int next = -1;

while ((next = reader.read()) != -1) {

fos.write(next);

}

// Sucessful finished

result = Activity.RESULT_OK;

} catch (Exception e) {

e.printStackTrace();

} finally {

if (stream != null) {

try {

stream.close();

} catch (IOException e) {

e.printStackTrace();

}

if (fos != null) {

try {

fos.close();

} catch (IOException e) {

e.printStackTrace();

}

Bundle extras = intent.getExtras();

if (extras != null) {

Messenger messenger = (Messenger) extras.get("MESSENGER");

Message msg = Message.obtain();

msg.arg1 = result;

msg.obj = output.getAbsolutePath();

try {

messenger.send(msg);

} catch (android.os.RemoteException e1) {

Log.w(getClass().getName(), "Exception sending message", e1);

}

5.Modify Androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.alarmservice"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="8"

android:targetSdkVersion="17" />

<uses-permission android:name="android.permission.WAKE_LOCK" />

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name="in.ac.srmuniv.alarmservice.MainActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

<service

android:name="in.ac.srmuniv.alarmservice.UpdatingService"

android:enabled="true" >

</service>

</application>

</manifest>

5.Run the application in the emulator.

Figure 1 Shows the parsed json message from file read from SD card downloaded from server by Intent Service and saved in SD card.Update of message from server is invoked by Alarm Manager Service every 15 seconds.If file is successfully downloaded a Toast message as shown will appear.

Figure 2 Shows the Alarm Manager Service stopped.Hence update service is also stopped.

6.Use XAMPP server start Apache server after coping the Message.php in htdocs/message folder.The Message.php PHP file which generates message.json file in server.

<html>

<body>

<form action="<?php $_PHP_SELF ?>" method="POST">

Message:

<input type="text" name="Message" />

<input type="submit" />

</form>

</body>

</html>

<?php

class Message {

public $message = "";

}

$obj = new Message();

if ($_POST) {

$fp = fopen('message.json', 'w');

$value = $_REQUEST['Message'];

$obj -> message = $value;

fwrite($fp, json_encode($obj));

fclose($fp);

exit();

}

Figure 3 Shows Message.php hosted in local server

Figure 4 Shows message.json file generated in local server on submitting message content in text box of Message.php
CODE EXPLANATION
Alarm manager is a system service,it set to repeating mode.Makes call to UpdatingService every 15 seconds through Alarm Manager,which would call every 15 seconds even out side the life time of the application .A PendingIntent is used to call the Service.The following code in MainActivity shows the setup of Alarm Manager for scheduling the download task.

calendar = (GregorianCalendar) Calendar.getInstance();

Intent myIntent = new Intent(MainActivity.this, UpdatingService.class);

Messenger messenger = new Messenger(handler);

myIntent.putExtra("MESSENGER", messenger);

myIntent.setData(Uri

.parse("http://10.0.2.2/message/message.json"));// nawinsandroidtutorial.site90.com/message

myIntent.putExtra("urlpath",

"http://10.0.2.2/message/message.json");

pendingIntent = PendingIntent.getService(MainActivity.this, 0,

myIntent, 0);

alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);

alarmManager.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(),

15000, pendingIntent);

The Intent Service would get the URL from MainActivity through intent extras, connects to the server and reads the json file and saves it in to the external storage(SD card).A parcelable Message carrying absolute path of the downloaded json file from server is sends message back to Activity handled by Handler class .The following code in UpdatingService sends message back to activity

Bundle extras = intent.getExtras();

if (extras != null) {

Messenger messenger = (Messenger) extras.get("MESSENGER");

Message msg = Message.obtain();

msg.arg1 = result;

msg.obj = output.getAbsolutePath();

try {

messenger.send(msg);

} catch (android.os.RemoteException e1) {

Log.w(getClass().getName(), "Exception sending message", e1);

}
Message handled by Handler in MainActivity through public void handleMessage(Message message) is the callback method of Handler called when message is send from UpdatingService.The received message contains the absolute path of downloaded json file.The readMessage() function reads the content from File in SD card parses the json "message" and displays in Textview as shown in Figure 1

Android Localization tutorial

2014-04-15T18:21:00.003-07:00

ANDROID LOCALIZATION TUTORIAL

Android will run on many devices in many regions .To reach the most users, your application should handle text, audio files, numbers, currency, and graphics in ways appropriate to the locales where your application will be used.In order to build multilingual Android apps you need to collect the texts into resource files and translate them. Once you provide the translation, Android OS will choose the resources that match user’s locale. If your application is available in several languages, Android will select the language that the device uses. Android loads text and media resources from the project’s ‘res’ directory. Additionally, Android can select and load resources from different directories, based on the current device configuration and locale.For example, if the code loads a string called ‘R.string.name’, Android will choose the correct value for that string at runtime by loading the appropriate strings.xml file from a matching ‘res/values’ directory.Example value-en for english,values-ta for tamil.Store respective translated text in different folders.
1.res/values-en for English

2.res/values-ta for Tamil

The application selects the resource files to load at run-time, based on the phone’s locale. If no locale-specific resources are available, it falls back on the defaults. For example, if we’re in Switzerland, and the phone’s language is set to French, Android will first look for a folder called fr-rCH. If it can’t find it, it looks for fr and if that’s not found too, it loads the resource files for the default language.

It does that for each resource type, so we can have Tamil strings with the default graphics, or any other combination of translated resources.

Once the localized string and image resources are added to the project workspace, the application is ready for testing. To test it, we can set different locales via Home > Menu > Settings > Language &input> Select Language.

Figure 1 Shows the anatomy of the project
This Demonstrative project portrays the localization concept in android, simply displays a form in two languages 1.English 2.Tamil on user choice of selection in menu.
1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_LocaleTutorial
Package name	in.ac.srmuniv.locale
Activity name	MainActivity
Layout xml name	activity_main

2.Copy the code to the file activity_main.xml in res/layout folder.

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:stretchColumns="1" >

<TableRow

android:id="@+id/tableRow1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:paddingBottom="25dp"

android:paddingTop="10dp" >

<FrameLayout

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1" >

<TextView

android:id="@+id/textView2"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:gravity="center"

android:text="@string/university"

android:textAlignment="center"

android:textAppearance="?android:attr/textAppearanceLarge" />

<ImageView

android:id="@+id/imageView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="right"

android:src="@drawable/locale2" />

</FrameLayout>

</TableRow>

<FrameLayout

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1" >

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:text="@string/name"

android:textAppearance="?android:attr/textAppearanceLarge" >

</TextView>

</FrameLayout>

<FrameLayout

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1" >

<EditText

android:id="@+id/editText1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:ems="10"

android:inputType="textPersonName" >

</EditText>

</FrameLayout>

</TableRow>

<FrameLayout

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1" >

<TextView

android:id="@+id/textView3"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:text="@string/discipline"

android:textAppearance="?android:attr/textAppearanceLarge" />

</FrameLayout>

<FrameLayout

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1" >

<Spinner

android:id="@+id/spinner1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:entries="@array/select" />

</FrameLayout>

</TableRow>

<FrameLayout

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_weight="1" >

<Button

android:id="@+id/button1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:gravity="center"

android:text="@string/submit_btn" />

</FrameLayout>

</TableRow>

<TableRow

android:id="@+id/tableRow2"

android:layout_width="wrap_content"

android:layout_height="wrap_content" >

<TextView

android:id="@+id/textView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text=""

android:textAppearance="?android:attr/textAppearanceLarge" />

</TableRow>

</TableLayout>

3.Create folders values-en,values-ta in res folder and copy strings.xml and styles.xml in to them.

string.xml in values-en folder

<?xml version="1.0" encoding="utf-8"?>

<string name="app_name">SRMForm</string>

<string name="university">SRM University </string>

<string name="discipline">Discipline</string>

<string name="submit_btn">Submit</string>

<string-array name="select">

<item>Engineering </item>

<item>Medical</item>

<item>Science</item>

</string-array>

</resources>

copy styles.xml in values-en folder from values folder.

string.xml in values-ta folder

<?xml version="1.0" encoding="utf-8"?>

<string name="app_name">Androidlocalization</string>

<string name="university">எஸ் ஆர் ரம் பல்கழைகழகம் </string>

<string name="discipline"> பிரிவு </string>

<string-array name="select">

<item>பொறிஈயல் </item>

<item>அறிவியல்</item>

</string-array>

</resources>

copy styles.xml in values-ta folder from values folder.
4.Copy the code in MainsActivity.java. Activity.

package in.ac.srmuniv.locale;

import java.util.Locale;

import com.mayuonline.tamilandroidunicodeutil.TamilUtil;

import android.view.View.OnClickListener;

import android.os.Bundle;

import android.app.Activity;

import android.content.Intent;

import android.content.res.Configuration;

import android.content.res.Resources;

import android.graphics.Typeface;

import android.util.DisplayMetrics;

import android.view.Menu;

import android.view.MenuInflater;

import android.view.MenuItem;

import android.view.View;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends Activity {

private Locale myLocale;

Button b1;

TextView t1;

ImageView logo;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

b1 = (Button) findViewById(R.id.button1);

t1 = (TextView) findViewById(R.id.textView1);

logo = (ImageView) findViewById(R.id.imageView1);

Locale current = getResources().getConfiguration().locale;

if (current.getDisplayLanguage().equals("Tamil")) {

logo.setImageResource(R.drawable.locale);

}

Typeface tf = Typeface.createFromAsset(getAssets(), "fonts/bamini.ttf");

// Encoding conversion

String tamilString = TamilUtil.convertToTamil(TamilUtil.BAMINI,

" தமிழிலும் படிவம் சமர்பிக்காலம்");

t1.setTypeface(tf);

t1.setText(tamilString);

b1.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Toast.makeText(getApplicationContext(), "Form submmited",

Toast.LENGTH_LONG).show();

}

});

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

MenuInflater inflater = getMenuInflater();

inflater.inflate(R.menu.main, menu);

return true;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// Handle item selection

switch (item.getItemId()) {

case R.id.tamil:

setLocale("ta");

return true;

case R.id.english:

setLocale("en");

return true;

default:

return super.onOptionsItemSelected(item);

}

public void setLocale(String lang) {

myLocale = new Locale(lang);

Resources res = getResources();

DisplayMetrics dm = res.getDisplayMetrics();

Configuration conf = res.getConfiguration();

conf.locale = myLocale;

res.updateConfiguration(conf, dm);

Intent refresh = new Intent(this, MainActivity.class);

startActivity(refresh);

finish();

}

4 Modify Androidmanifest.xml only on the highlighted part.

<?xml version="1.0"
encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.locale"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="14"

android:targetSdkVersion="17" />

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name="in.ac.srmuniv.locale.MainActivity"

android:label="@string/app_name"

android:theme="@android:style/Theme.Holo.Light.DarkActionBar">

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

5.Run the application in the emulator/device with tamil font available.

Figure 2 Shows when application is loaded the default Locale being English is loaded.
Figure 3 Shows When menu 'Tamil' is clicked from action bar menu the form Activity is reloaded.With Locale set to tamil programmatically string values are taken from values-ta folder.

CODE EXPLANATION

This demonstrative application has a simple form Activity.Choice of language can be selected through action bar menu.setLocale( String lang ) method has the following code which enable Locale change programmatically

myLocale = new Locale(lang);

Resources res = getResources();

DisplayMetrics dm = res.getDisplayMetrics();

Configuration conf = res.getConfiguration();

conf.locale = myLocale;

res.updateConfiguration(conf, dm);

Locale represents a language/country/variant combination. Locales are used to alter the presentation of information such as numbers or dates to suit the conventions in the region they describe.The constructor for Locale class takes two letter lowercase ISO language codes (such as "en") as defined by ISO 639-1. The country codes are two-letter uppercase ISO country codes (such as "US") as defined by ISO 3166-1. The variant codes are unspecified.

Any change in configuration needs to reload the activity hence we need to restart the activity to view the change

Intent refresh = new Intent(this, MainActivity.class);

startActivity(refresh);

finish();
Depending on the current locale choosing of appropriate audio/images/videos from different resources can be done programmatically.Here if the current display language is "Tamil" image is changed .The following code in onCreate() method demonstrate it.


Locale current = getResources().getConfiguration().locale;

           if (current.getDisplayLanguage().equals("Tamil")) {

                logo.setImageResource(R.drawable.locale);

           }


  Include language font bamini.ttf in assets/fonts folder.You can induct the font in to the code by the following code .Download TamilUtil library project from https://github.com/mayooresan/Android-TamilUtil for converting unicode to bammini,Anjal fonts


 Typeface tf =Typeface.createFromAsset(getAssets(), "fonts/bamini.ttf");
 This app uses a third party library TamilUtil which simply converts the tamil words in unicode to respective tamil fonts.Here the tamil words are converted String and is displayed in TextView after setting the typeface property to support the font.


           // Encoding conversion

           String tamilString = TamilUtil.convertToTamil(TamilUtil.BAMINI, "தமிழிலும் படிவம் சமர்பிக்காலம்");

        t1.setTypeface(tf);

        t1.setText(tamilString);
t1 is the TextView.

Calling Another Application Component in Your Application

2014-03-29T03:29:00.000-07:00

Calling Another Application Component in Your Application

To allow other apps to start your activity, you need to add an<intent-filter> element in your manifest file for the corresponding <activity> element.

When your app is installed on a device, the system identifies your intent filters and adds the information to an internal catalog of intents supported by all installed apps. When an app calls startActivity() or startActivityForResult(), with an implicit intent, the system finds which activity (or activities) can respond to the intent.

Explicit and implicit intents

Intents are asynchronous messages which allow application components to request functionality from other Android components. Intents allow you to interact with components from the same applications as well as with components contributed by other applications.

Explicit intents explicitly define the component which should be called by the Android system, by using the Java class as identifier.

Implicit intents are used to call other Activity from another application.Implicit Intents do not specify the Java class which should be called. They specify the action which should be performed and optionally one can add data directly to the Bundle via the overloaded putExtra() methods of the Intent objects. Extras are key/value pairs. The key is always of type String. As value you can use the primitive data types (int, float, ...) plus objects of type String, Bundle, Parceable and Serializable.if a call to another activity is through implicit intent,it is sent to the Android system, it searches for all components which are registered for the specific action and the fitting data type.If only one component is found, Android starts this component directly. If several components are identified by the Android system, the user will get a selection dialog and can decide which component should be used for the intent.

The Demonstrative application uses ZXing QR/Barcode scanner application for scanning QR code.

1.Import Zxing application as Shown in the Figure 1 and install it in to emulator/device as shown in Figure 2.If it is emulator then it should be camera enabled.

2.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_QRScanner
Package name	in.ac.srmuniv.qrscanner
Activity name	Scanner
Layout xml name	scanner

3..Copy the code to the file scanner.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/RelativeLayout1"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:layout_gravity="center"

android:orientation="vertical" >

<TextView

android:id="@+id/TextView1"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_alignParentTop="true"

android:gravity="center"

android:text="SRM QR_Scanner Application"

android:textSize="25sp" />

<ImageView

android:id="@+id/scanner"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_below="@+id/TextView1"

android:layout_centerHorizontal="true"

android:layout_marginTop="85dp"

android:background="@drawable/qrscannericon"

android:gravity="center"

android:text="Click to Scan "

android:textColor="#D70909" />

</RelativeLayout>

4.Copy the code in SRM_ScannerActivity.java. Activity.

package in.ac.srmuniv.qrscanner;

import in.ac.srmuniv.qrscanner.R;

import android.app.Activity;

import android.content.ActivityNotFoundException;

import android.content.Intent;

import android.net.Uri;

import android.os.Bundle;

import android.util.Log;

import android.view.Gravity;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.ImageView;

import android.widget.Toast;

public class SRM_ScannerActivity extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.scanner);

try {

ImageView scanner = (ImageView)findViewById(R.id.scanner);

scanner.setOnClickListener(new OnClickListener() {

public void onClick(View v) {

Intent intent = new Intent("com.google.zxing.client.android.SCAN");

intent.putExtra("SCAN_MODE", "QR_CODE_MODE");

startActivityForResult(intent, 0);

}

});

} catch (ActivityNotFoundException anfe) {

Log.e("onCreate", "Scanner Not Found", anfe);

}

public void onActivityResult(int requestCode, int resultCode, Intent intent) {

if (requestCode == 0) {

if (resultCode == RESULT_OK) {

String contents = intent.getStringExtra("SCAN_RESULT");

String format = intent.getStringExtra("SCAN_RESULT_FORMAT");

// Handle successful scan

Toast toast = Toast.makeText(this, "Content:" + contents + " Format:" + format , Toast.LENGTH_LONG);

toast.setGravity(Gravity.TOP, 25, 400);

toast.show();

Intent i = new Intent(android.content.Intent.ACTION_VIEW,

Uri.parse(contents));

startActivity(i);

} else if (resultCode == RESULT_CANCELED) {

// Handle cancel

Toast toast = Toast.makeText(this, "Scan was Cancelled!", Toast.LENGTH_LONG);

toast.setGravity(Gravity.TOP, 25, 400);

toast.show();

}

5.Modify the AndroidManifest.xml with necessary permission added.

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.qrscanner"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk android:minSdkVersion="15" />

<uses-permission android:name="android.permission.CAMERA"/>

<uses-feature android:name="android.hardware.camera.autofocus"/>

<uses-permission android:name="android.permission.INTERNET"/>

<uses-permission android:name="android.permission.VIBRATE"/>

<uses-permission android:name="android.permission.FLASHLIGHT"/>

<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/>

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

<application

android:icon="@drawable/ic_launcher"

android:label="@string/app_name" >

<activity

android:name=".ScannerActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

6.Run the application in device

Figure 3 Shows SRM_QRScannerActivity of SRM_QRScanner application when launched.

Figure 4 Shows on Image Click Capture Activity of ZXing application is called

Figure 5 Shows Capture Activity on returning result send the scanned data content extracted from QRCode
back to SRM_QRScanneractivity which inturn calls a browser through implicit intent
CODE EXPLANATION

In this application QR Code scanner we have to install zxing application which do both barcode and qrcode scanning.Download either source code or apk from the following link https://code.google.com/p/zxing/downloads/list.Figure 1 and 2 shows the downloaded ZXing.zip library is extracted and imported to our project and installed.The following code is an exert from AndroidManifest.xml file of ZXing project.The CaptureActivity's entry in manifest file has an intent filter with action name ""com.google.zxing.client.android.SCAN" which we have used as implicit intent call in our SRM_QRScanner application to call upon the Activity on a button click.The CaptureActivity activity from ZXing application (which is already installed) is called which returns the result of the scanned content emdeded in the QRCode.

<activity android:name=".CaptureActivity"

android:screenOrientation="landscape"

android:clearTaskOnLaunch="true"

android:stateNotNeeded="true"

android:configChanges="orientation|keyboardHidden"

android:theme="@android:style/Theme.NoTitleBar.Fullscreen"

android:windowSoftInputMode="stateAlwaysHidden">

<intent-filter>

</intent-filter>

<intent-filter>

</intent-filter>

<intent-filter>

</intent-filter>

<intent-filter>

</intent-filter>

<intent-filter>

</intent-filter>

<intent-filter>

</intent-filter>

</activity>

In our example SRM_QRScannerActivity following code snippet calls the CaptureActivity in ZXing application through implicit intent call through action message and passes extra data about type of scan.

Intent intent = new Intent("com.google.zxing.client.android.SCAN");

intent.putExtra("SCAN_MODE", "QR_CODE_MODE");

startActivityForResult(intent, 0);
The receiving component can access this information via the getAction() and getData() methods on the Intent object. This Intent object can be retrieved via the getIntent() method.The component which receives the intent can use the getIntent().getExtras() method call to get the extra data.

The called Activity in ZXing application receives intent message.It may be registered to multiple action messages.Hence it gets the intent action message and extracts the data.

Intent intent=getIntent();

Intent intent = getIntent();

.................

if (intent != null) {

String action = intent.getAction();

String dataString = intent.getDataString();

If activity is called with the startActivityForResult() method call, you expect feedback from the called sub-activity. Once the sub-activity ends,the onActivityResult() method on the calling-activity is called and you can perform actions based on the result.

In the startActivityForResult() method call you can specify a result code to determine which activity you started. This result code is returned to you. The started activity can also set a result code which the caller can use to determine if the activity was canceled or not.

When the CaptureActivity finishes, it sends resultcode and also returns data which would be the data extracted from scanned image.It will be received in the SRM_QRScannerActivity the following code portrays it.

public void onActivityResult(int requestCode, int resultCode, Intent intent)

{

....

if (requestCode == 0) {

if (resultCode == RESULT_OK) {

String contents = intent.getStringExtra("SCAN_RESULT");

String format = intent.getStringExtra("SCAN_RESULT_FORMAT");

// Handle successful scan

1.Make ZXing project as Library project .

2Add it as Library in SRM_QRScanner application.

The Zxing Application can be made as Library to our SRM_QRScanner application then you can import the classes of Zxing application in to our application.and call the CaptureActivity through explict intent call.You need not install Zxing application now separately since it is integrated as Library to the project

3.Modify the Androidmanifest.xml file to include CaptureActivity for explict intent call.

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.qrscanner"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk android:minSdkVersion="15" />

<uses-permission android:name="android.permission.CAMERA" />

<uses-feature android:name="android.hardware.camera.autofocus" />

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.FLASHLIGHT" />

<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

<application

android:icon="@drawable/ic_launcher"

android:label="@string/app_name" >

<activity

android:name=".ScannerActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

<activity

android:name="com.google.zxing.client.android.CaptureActivity"

android:configChanges="orientation|keyboardHidden"

android:screenOrientation="landscape"

android:theme="@android:style/Theme.NoTitleBar.Fullscreen"

android:windowSoftInputMode="stateAlwaysHidden" >

<intent-filter>

</intent-filter>

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

4.Modify the SRM_QRScannerActivity.java.Activity.Add the import and modify the onClick() method as shown below.

import com.google.zxing.client.android.CaptureActivity;

.......

public void onClick(View v) {

//Intent intent = new Intent("com.google.zxing.client.android.SCAN");

Intent intent = new Intent(ScannerActivity.this,com.google.zxing.client.android.CaptureActivity.class);

.......

Instead of implicit intent call we have made explicit intent call by directly calling the activity by class name since ZXing application is now part of our application as library.The capture activity is imported in to SRM_QRScannerActivity.

5.Run the Application you will have the similar working result.

Android Widget Tutorial

2014-03-24T20:53:00.000-07:00

Android Widget Tutorial

Android operating system has unique features in which one can create interactive app widgets a small gadget or control that display in other applications such as the home screen Widgets can be very handy as they allow you to put your favourite applications on your homescreen in order to quickly access them. Some common widgets you have probably seen are music widget , weather widget , clock widget e.t.c.

Widgets can receive periodic updates such as RSS feeds, weather updates, and news articles. Most Android users expect their favorite applications to provide a widget for quick and easy access to information they need, an application executing a long-running task can publish the progress indicator as home screen widget.

We also have to take in to consideration widgets with constantly refreshing data will use battery life and consume data for those users on limited bandwidth mobile data plans. Please keep these factors in mind while you are creating widgets as your users will not be very happy if they get an unexpectedly large cellular bill or if their battery life decreases significantly after installing your widget.

Widgets a technical overview

A Widget runs as part of the process of its host. This requires that Widgets preserve the permissions of their application.To create a Widget one needs to extend AppWidgetProvider class which is basically a BroadcatReceiver.Widgets use RemoteViews to create there user interface. A RemoteView can be executed by another process with the same permissions as the original application. This way the Widget runs with the permissions of its defining application.The user interface for a Widget is defined by an BroadcastReceiver. This BroadcastReceiver inflates its layout into an object of type RemoteViews. This RemoteViews object is delivered to Android, which hands it over the HomeScreen application.

Widget Creation

To create a Widgets one has to 1.Define a layout file for widget2 .Create an XML file (AppWidgetProviderInfo) which describes the properties of the widget, e.g. size or the fixed update frequency..3Create a BroadcastReceiver which is used to build the user interface of the Widget.4.Enter the Widget configuration in the AndroidManifest.xml file.5.Optionaly you can specify a configuration activity which is called once a new instance of the widget is added to the widget host.

Widget size

A Widget will take a certain amount of cells on the homescreen. A cell is usually used to display the icon of one application. As a calculation rule you should define the size of the widget with the formula: ((Number of columns / rows)* 74) - 2. These are device independent pixels and the -2 is used to avoid rounding issues.

As of Android 3.1 a Widgets can be flexible in size, e.g. the user can make it larger or smaller. To enable this forWidgets you can use the android:resizeMode="horizontal|vertical" attribute in the XML configuration file for the widget.

AppWidgetprovider class methods and Lifecycle.

The following table provides purpose of various AppWidgetprovider class which is the class needed to create an AppWidget. The AppWidgetProvider class implements the onReceive() method, extracts the required information and calls the following widget lifecycle methods.

As you can add several instances of a widget to the homescreen you have lifecycle methods which are called only for the first instance added / removed to the homescreen and others which are called for every instance of your widget.

void onAppWidgetOptionsChanged(Context context, AppWidgetManager appWidgetManager, int appWidgetId, Bundle newOptions)

Called in response to the ACTION_APPWIDGET_OPTIONS_CHANGED broadcast when this widget has been layed out at a new size.

void onDeleted(Context context, int[] appWidgetIds)

Called in response to the ACTION_APPWIDGET_DELETED broadcast when one or more AppWidget instances have been deleted. Override this method to implement your own AppWidget functionality.

void onDisabled(Context context) Called once the last instance of your widget is removed from the homescreen.Called in response to the ACTION_APPWIDGET_DISABLED broadcast, which is sent when the last AppWidget instance for this provider is deleted. Override this method to implement your own AppWidget functionality.

void onEnabled(Context context)

Called the first time an instance of your widget is added to the homescreen.Called in response to the ACTION_APPWIDGET_ENABLED broadcast when the a AppWidget for this provider is instantiated. Override this method to implement your own AppWidget functionality.

void onReceive(Context context, Intent intent)

Implements onReceive(Context, Intent) to dispatch calls to the various other methods on AppWidgetProvider.

void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds)

Called for every update of the widget. Contains the ids of appWidgetIds for which an update is needed. Note that this may be all of the AppWidget instances for this provider, or just a subset of them, as stated in the methods JavaDoc. For example if more than one widget is added to the homescreen, only the last one changes (until reinstall).Called in response to the ACTION_APPWIDGET_UPDATE broadcast when this AppWidget provider is being asked to provide RemoteViews for a set of AppWidgets. Override this method to implement your own AppWidget functionality.

All long running operations in these methods should be performed in a service, as the execution time for a broadcast receiver is limited. Using asynchronous processing in the onReceive() method does not help as the system can kill the broadcast process after his onReceive() method. A widget is restricted in the View classes it can use. As layouts you can use the FrameLayout, LinearLayout andRelativeLayout classes.As views you can use AnalogClock, Button, Chromometer, ImageButton, ImageView,ProgressBar and TextView. As of Android 3.0 more views are available: GridView, ListView, StackView, ViewFlipper and AdapterViewFlipper.The only interaction that is possible on the Views of a Widget is via on OnClickListener. This OnClickListener can be registered on a widget and is triggered by the user.

Remote Views

The workhorse behind Android AppWidgets is the RemoteViews widget. RemoteViews is a parcelable data structure (so it can be sent through Android IPC) that captures an entire view structure. The creator of the RemoteViews sets up this data structure, by specifying the base layout and setting field values. This has no effect on the UI and therefore background components like services, broadcast event handlers, etc. can also do it. In fact, AppWidgets are broadcast event receivers, they process broadcasts from Launcher and respond with RemoteViews. When the RemoteViews data structure is received and deserialized, it can be applied to any ViewGroup of the UI and can therefore appear on the UI of another application. From this point of view, it works just like a hypertext document except that RemoteViews describes Android views and not general web controls.

4. Widget updates

A Widget gets its data on a periodic timetable. There are two methods to update a widget, one is based on an XML configuration file and the other is based on the Android AlarmManager service.

In the widget configuration file you can specify a fixed update interval. The system will wake up after this time interval and call your broadcast receiver to update the widget. The smallest update interval is 1800000 milliseconds (30 minutes).

The AlarmManager allows you to be more resource efficient and to have a higher frequency of updates. To use this approach you define a service and schedule this service via the AlarmManager regularly. This service updates the widget.

Please note that a higher update frequency will wake up the phone from the energy safe mode. As a result your widget consumes more energy.
This Demonstrative project creates a Home screen widget which fetches all the contacts list in ascending order and makes it available with photo,name and number available in widget in a customized manner so that user can move through the contacts with simple tap on forward and reverse buttons and make call to people easily.

1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_WidgetTutorial
Package name	in.ac.srmuniv.widgettutorial
Activity name	-
Layout xml name	Contacts.xml

2.Copy the code to the file contacts.xml in res/layout folder

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/LinearLayout1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:background="@drawable/contactsviewbackground"

android:orientation="vertical" >

<Button

android:id="@+id/phone"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center|bottom"

android:background="@drawable/buttonbackground"

android:text="phone no"

android:textColor="#003399"

android:textSize="26sp"

android:textStyle="bold" />

<FrameLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center">

<ImageView

android:id="@+id/widget_image"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:layout_gravity="center"

android:src="@drawable/me" />

<RelativeLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

<TextView

android:id="@+id/name"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:gravity="center|top"

android:layout_alignParentTop="true"

android:text="Name"

android:textColor="#003399"

android:textSize="24sp"

android:textStyle="bold" />

<ImageView

android:id="@+id/imageButton1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentBottom="true"

android:src="@drawable/forwardicon"

android:layout_gravity="bottom"/>

</RelativeLayout>

</FrameLayout>

</LinearLayout>

3.Copy the code in ContactsWidgetProvider.java. AppWidgetProvider.

package in.ac.srmuniv.widgettutorial;

import java.io.FileNotFoundException;

import java.io.IOException;

import in.ac.srmuniv.widgettutorial.R;

import android.app.PendingIntent;

import android.appwidget.AppWidgetManager;

import android.appwidget.AppWidgetProvider;

import android.content.ComponentName;

import android.content.Context;

import android.content.Intent;

import android.database.Cursor;

import android.graphics.Bitmap;

import android.net.Uri;

import android.provider.ContactsContract;

import android.provider.MediaStore;

import android.util.Log;

import android.widget.RemoteViews;

public class ContactsWidgetProvider extends AppWidgetProvider {

private static int clickCount = 0;

private static boolean flag=true;

String Number="09840889310";

@Override

public void onUpdate(Context context, AppWidgetManager appWidgetManager,

int[] appWidgetIds) {

RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.contacts);

remoteViews.setOnClickPendingIntent(R.id.widget_image, buildPendingIntent(context,"in.ac.srmuniv.action.CHANGE_PICTURE"));

remoteViews.setOnClickPendingIntent(R.id.phone,buildPendingIntent(context,"in.ac.srmuniv.action.MAKE_PHONE"));

remoteViews.setOnClickPendingIntent(R.id.forwardbackimage

pushWidgetUpdate(context, remoteViews);

}

@Override

public void onReceive(Context context, Intent intent) {

if(intent.getAction().equals("in.ac.srmuniv.action.CHANGE_PICTURE")){

Log.w("Widget", "OnRecive called");

// Build the intent to call the service

updateWidgetPictureListener(context);

}

if(intent.getAction().equals("in.ac.srmuniv.action.MAKE_PHONE")){

Log.w("Widget", "BUTTON PRESSED");

Intent callIntent = new Intent(Intent.ACTION_CALL);

callIntent.setFlags (Intent.FLAG_ACTIVITY_NEW_TASK);

callIntent.setData(Uri.parse("tel:"+updateWidgetButtonListener(context)));

context.startActivity(callIntent);

}

if(intent.getAction().equals("in.ac.srmuniv.action.FORWARD_BACK")){

Log.w("Widget", "Forward Back");

RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.contacts);

if(flag)

{

flag=false;

remoteViews.setImageViewResource(R.id.forwardbackimage

}

else

{

flag=true;

remoteViews.setImageViewResource(R.id.forwardbackimage

}

pushWidgetUpdate(context.getApplicationContext(), remoteViews);

}

super.onReceive(context, intent);

}

public PendingIntent buildPendingIntent(Context context,String action) {

Intent intent = new Intent();

intent.setAction(action);

return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

}

public static void pushWidgetUpdate(Context context, RemoteViews remoteViews) {

ComponentName myWidget = new ComponentName(context, ContactsWidgetProvider.class);

AppWidgetManager manager = AppWidgetManager.getInstance(context);

manager.updateAppWidget(myWidget, remoteViews);

}

private String updateWidgetButtonListener(Context context) {

Cursor phones = context.getContentResolver().query(

ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,null,

null,"UPPER(" + ContactsContract.Contacts.DISPLAY_NAME + ") ASC");

int count = phones.getCount();

Log.w("Widget","Number " + Number+" and count: "+count);

phones.moveToPosition(((clickCount-1)%count)) ;

String Number = phones

.getString(phones

.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

phones.close();

return Number;

}

private void updateWidgetPictureListener(Context context) {

Cursor phones = context.getContentResolver().query(

ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,null,

null,"UPPER(" + ContactsContract.Contacts.DISPLAY_NAME + ") ASC");

int count = phones.getCount();

Log.w("Widget","count: "+count);

if(flag)

phones.moveToPosition(clickCount++%count) ;

else

{

phones.moveToPosition(clickCount--%count) ;

if(clickCount==0)

clickCount=count;

}

Log.w("Widget", "ClickCount"+clickCount);

String Name = phones

.getString(phones

.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));

String Number = phones

.getString(phones

.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

String image_uri = phones

.getString(phones

.getColumnIndex(ContactsContract.CommonDataKinds.Phone.PHOTO_URI));

Log.w("Widget", Name + ", Number " + Number

+ ", image_uri " + image_uri);

phones.close();

RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.contacts);

Bitmap bitmap;

try {

Uri imageUri = Uri.parse( image_uri);

bitmap = MediaStore.Images.Media.getBitmap(context.getContentResolver(), imageUri);

remoteViews.setImageViewBitmap(R.id.widget_image,bitmap);

}

catch (NullPointerException e) {

remoteViews.setImageViewResource(R.id.widget_image,R.drawable.personicon);

}catch (FileNotFoundException e) {

remoteViews.setImageViewResource(R.id.widget_image,R.drawable.personicon);

} catch (IOException e) {

remoteViews.setImageViewResource(R.id.widget_image,R.drawable.personicon);

}

remoteViews.setTextViewText(R.id.name, Name);

remoteViews.setTextViewText(R.id.phone,Number);

pushWidgetUpdate(context.getApplicationContext(), remoteViews);

}

4.Create xml folder in res directory and add app-widgetprovider xml file named as contacts_widgetprovider.xml

<?xml version="1.0" encoding="utf-8"?>

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"

android:initialLayout="@layout/contacts"

android:minHeight="146dp"

android:minWidth="146dp"

android:updatePeriodMillis="180000"

</appwidget-provider>

5.Create buttonbackground.xml file in drawable-hpdi folder for drawing button background.

<?xml version="1.0" encoding="UTF-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

android:shape="rectangle" >

<stroke

android:width="2dp"

android:color="#FFFFFFFF" />

<gradient

android:angle="225"

android:endColor="#DD0D6AD9"

android:startColor="#DD86F4F3" />

<corners

android:bottomLeftRadius="7dp"

android:bottomRightRadius="7dp"

android:topLeftRadius="7dp"

android:topRightRadius="7dp" />

</shape>

6.Similarly Create contactsbackground.xml file in drawable-hpdi folder for drawing contacts image background.

<?xml version="1.0" encoding="UTF-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

android:shape="rectangle" >

<stroke

android:width="2dp"

android:color="#FFFFFFFF" />

<gradient

android:angle="225"

android:endColor="#EE320972"

android:startColor="#EE98F0EB" />

<corners

android:bottomLeftRadius="7dp"

android:bottomRightRadius="7dp"

android:topLeftRadius="7dp"

android:topRightRadius="7dp" />

</shape>

7.Modify the AndroidManifest file with added permissions as listed below.

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.widgettutorial"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="11"

android:targetSdkVersion="17" />

<uses-permission android:name="android.permission.READ_CONTACTS" />

<uses-permission android:name="android.permission.CALL_PHONE" />

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<intent-filter>

</intent-filter>

<meta-data

android:name="android.appwidget.provider"

android:resource="@xml/contacts_widgetprovider" />

</receiver>

</application>

</manifest>

8.Run the program in emulator/device with already added contacts preferably with images of people contacts.

9.Drag the widget from widgets to Home screen to instaniate widget.

Figure 1 Shows Widget when installed. Figure 2 Shows when widget is dragged to Home Screen

10.Click the contact to change contacts.Click forward and reverse button to move contacts forward or backword.Click contact button to make phone call.

Figure 3 Shows tapping the image will move to next contact in descending direction Figure 4 Shows moving contacts from list in ascending direction.

Figure 5 Shows When phone number button is pressed phone call Activity is called

Code Explanation::
The widget layout is designed to have a compact and easy access to user.When widget is loaded to the home screen default image and text are shown (Refer Figure 2).Frame layout is used .A overlap of contacts people picture,name and forward/reverse contacts navigation buttons appear on top of it .
When Widget is dragged to the Home Screen onEnabled() method followed by onUpgrade() method is called.OnUpgarde() method is called when ever AppWidget provider is being asked to provide RemoteViews for a set of AppWidgets.We have registered for broadcast action ACTION_APPWIDGET_UPDATE in our manifest file.
There are three remote views in our application.Event handling for all these three views are registered with pending intent which will broadcast action message.It will be received by onRecive() method in AppWidgetProvider class.onRecive() method will dispatch calls to various other methods of AppWidgetProvider.
1.widget_image: It is an image view when clicked onRecive() method is called with broadcast action messag"in.ac.srmuniv.CHANGE_PICTURE". Contacts content provider Cursor is moved to next (or) previous contact.Contacts PhotoUri, phone number and name are fetched.widget_image will display person photo from Contacts photo uri if photo does not exist default image is displayed.Phone number is updated in phone button Name of the contact is displayed in TextView.
2.forwardbackimage:It is also an image view when clicked onRecive() method is called with broadcast action messag"in.ac.srmuniv.FORAWRD_BACK".Here a toggle flag is changed to decide the logic either to move contact cursor forward or backward.The toggle flag enables to fetch contacts in ascending order or descending order on widget_image click (Refer Figure 3 and Figure 4).

if(flag)

phones.moveToPosition(clickCount++%count) ;

else

{

phones.moveToPosition(clickCount--%count) ;

if(clickCount==0)

clickCount=count;

}
3.phone: It is a Button when clicked onRecive() method is called with broadcast action messag"in.ac.srmuniv.MAKE_PHONE". On click of the phone_button phone call intent will be called.with phone no fetched from current cursor position from the Contacts content provider.The following code shows the Activity call from a widget.(Refer Figure 5)

Intent callIntent = new Intent(Intent.ACTION_CALL);

callIntent.setFlags (Intent.FLAG_ACTIVITY_NEW_TASK);

callIntent.setData(Uri.parse("tel:"+updateWidgetButtonListener(context)));

context.startActivity(callIntent);

Every time pushWidgetUpdate(context.getApplicationContext(), remoteViews);
is called to update views .

Context and Application Context in Android Tutorial

2014-03-23T02:51:00.002-07:00

Context and Application Context in Android Tutorial

Purpose of Context and Application Context in Android is explained in this section

Context:

Its the context of current state of the application/object. It lets newly created objects understand what has been going on. Typically you call it to get information regarding another part of your program (activity, package/application)You can get the context by invoking getApplicationContext(), getContext(), getBaseContext() or this (when in the activity class).

Things that involve context are

1. Loading a resource.

2. Launching a new activity.

3. Creating views.

4.obtaining system service

Application Context

Application class extends Context class.Every Application has a context, and Android guarantees that Application context will exist as a instance across your application.Many times you may need to store the state of your app or a need a variable across multiple Activities,services and other java classes . Android provides an easy option for doing this – the global application context.

Custom adapters
Android Adapter is a bridge between the View (e.g. ListView) and the underlying data for that view. An adapter manages the data and adapts the data to the individual rows (listItems) of the view.We bind the adapter with Android listview via setAdapter method.Once we have a reference to the view, we can get the data from the data source either in an Array list or a cursor. We can then bind the data to the view items. All this is done in getView Method.By default, ArrayAdapter expects a Layout with single TextView. If you want to use more complex views, please avoid ArrayAdapter and use custom adapter.ArrayAdapter is also an implementation of BaseAdapter

BaseAdapter is a common base class of a general implementation for an Adapter that can be used in ListView. BaseAdapter can be extended to create a custom Adapter to suit your need of building a custom listitem.

Understanding Custom Adapter Methods

Methods of the custom adapter.are detailed below.

getCount() : This method tells the listview the number of rows it will require. This count can come from your data source. It can be the size of your Data Source. If you have your datasource as a list of objects, this value will be the size of the list.
Object getItem(int arg0): We have 2 method implementation of getItem. This method returns an object. This method helps ListView to get data for each row. The parameter passed is the row number starting from 0. In our List of Objects, this method will return the object at the passed index.
long getItemId(int arg0) : You can ignore this method. It just returns the same value as passed. This in general helps ListView to map its rows to the data set elements.
getView : This is the most important method. This method will be called to get the View for each row. This is the method where we can use our custom listitem and bind it with the data. The fist argument passed to getView is the listview item position ie row number. The second parameter is recycled view reference(as we know listview recycles a view, you can confirm through this parameter). Third parameter is the parent to which this view will get attached to.

Data Source can any custom object(user defined class objects).
The Demonstrative Project takes product and its price details from user and updates it in to Custom ListView and computes total price of the product added to list.User has choice to delete any item from the list
1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_ApplicationContextTutorial
Package name	in.ac.srmuniv.applicationcontextactivities
Activity name	MainActivity
Layout xml name	main

2.Create a java file named ListProductModel.java under the following mentioned package

package in.ac.srmuniv.applicationcontextjavaclasses;

public class ListProductModel {

private String ProductName="";

private double price;

/*********** Set Methods ******************/

public void setProductName(String ProductName)

{

this.ProductName = ProductName;

}

public void setprice(double price)

{

this.price = price;

}

/*********** Get Methods ****************/

public String getProductName()

{

return this.ProductName;

}

public double getprice()

{

return this.price;

}

3.Create a java file named ProductManagerApplication.java under the following mentioned package

package in.ac.srmuniv.applicationcontextandroidclasses;

import in.ac.srmuniv.applicationcontextjavaclasses.ListProductModel;

import java.util.ArrayList;

import android.app.Application;

public class ProductManagerApplication extends Application{

private ArrayList<ListProductModel> productsList;

private double totalPrice;

@Override

public void onCreate() {

super.onCreate();

if (null == productsList) {

productsList = new ArrayList<ListProductModel>();

}

public void setCurrentProducts(ArrayList<ListProductModel> productsList) {

this.productsList = productsList;

}

public ArrayList<ListProductModel> getCurrentProducts() {

return productsList;

}

public void addProduct(ListProductModel t) {

assert(null != t);

if (null == productsList) {

productsList = new ArrayList<ListProductModel>();

}

productsList.add(t);

calcProductTotal();

}

private void calcProductTotal() {

double price=0.0;

for(ListProductModel prod : productsList) //use for-each loop

{

price +=prod.getprice();

}

totalPrice=price;

}

public void removeProduct(ListProductModel l)

{

productsList.remove(l);

calcProductTotal();

}

public double getTotalprice()

{

return totalPrice;

}

5.Create a java file named ProductManagerApplication.java under the following mentioned package

package in.ac.srmuniv.applicationcontextandroidclasses;

import in.ac.srmuniv.applicationcontextactivities.MainActivity;

import in.ac.srmuniv.applicationcontextjavaclasses.ListProductModel;

import in.ac.srmuniv.applicationcontextactivities.R;

import java.util.ArrayList;

import android.app.Activity;

import android.content.Context;

import android.util.Log;

import android.view.LayoutInflater;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.TextView;

public class CustomAdapter extends BaseAdapter implements OnClickListener {

/*********** Declare Used Variables *********/

private Activity activity;

private ArrayList<ListProductModel> data;

private static LayoutInflater inflater=null;

ListProductModel tempValues=null;

int i=0;

/************* CustomAdapter Constructor *****************/

public CustomAdapter(Activity a, ArrayList<ListProductModel> d) {

/********** Take passed values **********/

activity = a;

data=d;

/*********** Layout inflator to call external xml layout () ***********/

inflater = ( LayoutInflater )activity.

getSystemService(Context.LAYOUT_INFLATER_SERVICE);

}

/******** What is the size of Passed Arraylist Size ************/

public int getCount() {

if(data.size()<=0)

return 1;

return data.size();

}

public Object getItem(int position) {

return position;

}

public long getItemId(int position) {

return position;

}

public void forceReload() {

notifyDataSetChanged();

}

/********* Create a holder Class to contain inflated xml file elements *********/

public static class ViewHolder{

public TextView text;

public TextView text1;

}

/****** Depends upon data size called for each row , Create each ListView row *****/

public View getView(int position, View convertView, ViewGroup parent) {

View vi = convertView;

ViewHolder holder;

if(convertView==null){

/****** Inflate product_row.xml file for each row ( Defined below ) *******/

vi = inflater.inflate(R.layout.product_row, null);

/****** View Holder Object to contain product_row.xml file elements ******/

holder = new ViewHolder();

holder.text = (TextView) vi.findViewById(R.id.text);

holder.text1=(TextView)vi.findViewById(R.id.text1);

/************ Set holder with LayoutInflater ************/

vi.setTag( holder );

}

else

holder=(ViewHolder)vi.getTag();

if(data.size()<=0)

{

holder.text.setText("No Added Product");

holder.text1.setText("");

}

else

{

/***** Get each Model object from Arraylist ********/

tempValues=null;

tempValues = ( ListProductModel ) data.get( position );

/************ Set Model values in Holder elements ***********/

holder.text.setText( tempValues.getProductName());

holder.text1.setText( new Double(tempValues.getprice()).toString() );

/******** Set Item Click Listner for LayoutInflater for each row *******/

vi.setOnClickListener(new OnItemClickListener( position ));

}

return vi;

}

@Override

public void onClick(View v) {

Log.v("CustomAdapter", "=====Row button clicked=====");

}

/********* Called when Item click in ListView ************/

private class OnItemClickListener implements OnClickListener{

private int mPosition;

OnItemClickListener(int position){

mPosition = position;

}

@Override

public void onClick(View arg0) {

MainActivity m = (MainActivity)activity;

/**** Call onItemClick Method inside MainActivity Class ( See Below )****/

m.onItemClick(mPosition);

}

6.Copy the code to the file main.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical" >

<RelativeLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:paddingTop="5dp"

android:paddingBottom="5dp" >

<Button

android:id="@+id/button1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_alignParentTop="true"

android:text="@string/addproduct_btn" />

<TextView

android:id="@+id/textView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignBaseline="@+id/button1"

android:layout_alignBottom="@+id/button1"

android:layout_toRightOf="@+id/button1"

android:text="@string/pricetotal_label"

android:textAppearance="?android:attr/textAppearanceMedium" />

<TextView

android:id="@+id/textView2"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentRight="true"

android:layout_centerVertical="true"

android:text=""

android:textAppearance="?android:attr/textAppearanceLarge" />

</RelativeLayout>

<ListView

android:id="@+id/list"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:scrollbars="vertical"

android:dividerHeight="2dp">

</ListView>

</LinearLayout>

7.Copy the code to the file product_row.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:paddingTop="0dip" android:layout_gravity="top"

<TextView

android:id="@+id/text"

android:layout_height="wrap_content"

android:layout_width="wrap_content"

android:layout_weight="1"

android:layout_gravity="left|center_vertical"

android:textSize="16sp"

android:layout_marginLeft="10dip"

android:layout_marginTop="4dip"

android:textColor="#000000"

android:layout_span="1"

</TableRow>

<TextView

android:text=""

android:id="@+id/text1"

android:layout_height="wrap_content"

android:layout_width="wrap_content"

android:layout_weight="1"

android:layout_gravity="left|center_vertical"

android:textSize="16sp"

android:textColor="#000000"

android:layout_marginLeft="10dip"

android:layout_marginTop="4dip"

android:gravity="left"/>

</TableRow>

</TableLayout>

8.Copy the code in MainActivity.java. Activity.

package in.ac.srmuniv.applicationcontextactivities;

import in.ac.srmuniv.applicationcontextandroidclasses.CustomAdapter;

import in.ac.srmuniv.applicationcontextandroidclasses.ProductManagerApplication;

import in.ac.srmuniv.applicationcontextjavaclasses.ListProductModel;

import in.ac.srmuniv.applicationcontextactivities.R;

import java.util.ArrayList;

import android.os.Bundle;

import android.app.Activity;

import android.app.AlertDialog;

import android.content.DialogInterface;

import android.content.Intent;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ListView;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends Activity {

ListView list;

CustomAdapter adapter; public ArrayList<ListProductModel> CustomListViewValuesArr = new ArrayList<ListProductModel>();

private ProductManagerApplication globalVar;

private TextView total;

private AlertDialog deleteProductDialog;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Button addProduct=(Button)findViewById(R.id.button1);

total=(TextView)findViewById(R.id.textView2);

addProduct.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Intent intent = new Intent(MainActivity.this, AddProductActivity.class);

startActivity(intent);

}

});

globalVar=(ProductManagerApplication)getApplicationContext();

/******** Take some data in Arraylist ( CustomListViewValuesArr ) ***********/

setListData();

//Resources res =getResources();

list= ( ListView )findViewById( R.id.list ); // List defined in XML ( See Below )

/**************** Create Custom Adapter *********/

adapter=new CustomAdapter( this, CustomListViewValuesArr );

list.setAdapter( adapter );

}

@Override

protected void onResume() {

super.onResume();

adapter.forceReload();

total.setText(new Double(globalVar.getTotalprice()).toString());

}

/****** Function to set data in ArrayList *************/

public void setListData()

{

CustomListViewValuesArr =globalVar.getCurrentProducts();

}

/***************** This function used by adapter ****************/

public void onItemClick(int mPosition)

{

if(!CustomListViewValuesArr.isEmpty())

{

final int pos=mPosition;

deleteProductDialog = new AlertDialog.Builder(this)

.setTitle(R.string.dialogbox_title)

.setMessage(R.string.dialogbox_message)

.setNeutralButton(R.string.dialogbox_deletebtn, new AlertDialog.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

deteleProduct(pos);

}

})

.setNegativeButton(android.R.string.cancel, new AlertDialog.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

deleteProductDialog.cancel();

}

})

.create();

deleteProductDialog.show();

}

protected void deteleProduct(int mPosition) {

ListProductModel tempValues = ( ListProductModel ) CustomListViewValuesArr.get(mPosition);

globalVar.removeProduct(tempValues);

adapter.forceReload();

total.setText(new Double(globalVar.getTotalprice()).toString());

// SHOW ALERT

Toast.makeText(this,

""+tempValues.getProductName()

+" Removed",

Toast.LENGTH_LONG)

.show();

}

9.Copy the code to the file add_product.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<TextView

android:id="@+id/tasks_title"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/productname_label"

android:textAppearance="?android:attr/textAppearanceMedium"

<EditText

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:focusable="true"

android:id="@+id/task_name"/>

<TextView

android:id="@+id/textView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/productprice_label"

android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText

android:id="@+id/price"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:inputType="numberDecimal"

android:ems="10" >

</EditText>

<Button

android:id="@+id/add_button"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/addproduct_btn"/>

<Button

android:id="@+id/cancel_button"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/quitentry_btn"/>

</LinearLayout>

6.Copy the code in AddProductActivity.java. Activity.

package in.ac.srmuniv.applicationcontextactivities;

import n.ac.srmuniv.applicationcontextandroidclasses.ProductManagerApplication;

import in.ac.srmuniv.applicationcontextjavaclasses.ListProductModel;

import in.ac.srmuniv.applicationcontextactivities.R;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

public class AddProductActivity extends Activity {

private EditText productNameEditText;

private EditText productpriceEditText;

private Button addButton;

private Button cancelButton;

private ProductManagerApplication globalVar;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.add_product);

globalVar=(ProductManagerApplication)getApplicationContext();

productNameEditText = (EditText)findViewById(R.id.task_name);

productpriceEditText = (EditText)findViewById(R.id.price);

addButton = (Button)findViewById(R.id.add_button);

cancelButton = (Button)findViewById(R.id.cancel_button);

addButton.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

addTask();

}

});

cancelButton.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

cancel();

}

});

}

protected void addTask() {

String ProductName = productNameEditText.getText().toString();

ListProductModel t = new ListProductModel();

t.setProductName(ProductName);

try {

t.setprice(Double.parseDouble(productpriceEditText.getText().toString()));

globalVar.addProduct(t);

productNameEditText.setText("");

productpriceEditText.setText("");

} catch (NumberFormatException e) {

Toast.makeText(getApplicationContext(),

"Product not added",

Toast.LENGTH_LONG)

.show();

e.printStackTrace();

}

protected void cancel() {

finish();

}

10.Copy the code to the file strings.xml in res/values folder

<?xml version="1.0" encoding="utf-8"?>

<string name="app_name">SRM_ApplicationContextTutorial</string>

<string name="action_settings">Settings</string>

<string name="dialogbox_title">Product Deletion</string>

<string name="dialogbox_message">Are you of Deleting product</string>

<string name="dialogbox_deletebtn">Delete</string>

<string name="addproduct_btn">Add Product</string>

<string name="pricetotal_label">Total Price =</string>

<string name="productname_label">Product Name</string>

<string name="productprice_label">Product Price</string>

</resources>

11. Modify Androidmanifest.xml

<?xml version="1.0"
encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.applicationcontextactivities"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="8"

android:targetSdkVersion="17" />

<application

android:name="in.ac.srmuniv.applicationcontextandroidclasses.ProductManagerApplication"

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name="in.ac.srmuniv.applicationcontextactivities.MainActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</activity>

</application>

</manifest>

12.Run the application in the emulator.

Figure 1 Shows Empty List View with products to be added Figure 2 shows when button is pressed AddProduct Activity being called where price and product entries are added until Quit button pressed.

Figure 3 Shows the List of products added Figure 4 shows when an item is selected it calls Dialog box to ensure deletion of the product item.

Figure 5 Shows when an item is deleted..

CODE EXPLANATION

MainActivity contains Custom List View which lists the product items to be added..Clicking "Add Product" button calls AddProductActivity which allows user to enter product name and price and clicking "Add Product" button in AddProductActivity adds the product in to ArrayList.ArrayList<ListProductmodel> productList which is used as global variable since it is an attribute of ProductManagerApplication classs.

The following code shows how to use how to use global variable across application in various android components such as Activities,Services etc for sharing data In our application declaration of Application object is done in MainActivity as well as AddProductActivity.

private ProductManagerApplication globalVar;

Instantiation of Application object is done in both Activities as shown below in onCreate() method

globalVar=(ProductManagerApplication)getApplicationContext();

Method calls on addProduct(),removeProducts(),calcProductTotal() in Application class through instance created in MainActivity and AddProduct Activity.They will share the common instance hence data can be shared.When Product is added in AddProduct Activity it is reflected in MainActivity ListView and Total price.

Purpose of Context is explained through Custom List adapter.Here we use custom adapter which extends BaseAdapter.Data source is ListProductModel.

getView

This is the method where listitem is binded to the ListView. Since we want to use our own list item, let's get the reference of our custom list item. To add any new layout to an existing layout, you need to inflate the other layout. To inflate a layout you need to get the reference of LayoutInflater.
private static LayoutInflater inflater=null;
……..

/*********** Layout inflator to call external xml layout () ***********/

inflater = ( LayoutInflater )activity.

getSystemService(Context.LAYOUT_INFLATER_SERVICE);

Context.LAYOUT_INFLATER_SERVICE. Getsystem service method is present in context. To get the reference of context, you can call this pointer on Activity,Here the MainActivity context is passed to this CustomAdapter class in order to serve the activity to fetch external xml resourse and inflate its listview

adapter=new CustomAdapter( this, CustomListViewValuesArr );

Once you have the layout inflater object, you just need to call inflate method on it.

vi = inflater.inflate(R.layout.product_row, null);

This inflates method takes 3 parameters, the layout which you want to add, the parent where the layout is being added , and third a boolean to attach the root to it's parent.

Through ViewHolder you can set the values of View elements in product_row.xml

holder = new ViewHolder();

holder.text = (TextView) vi.findViewById(R.id.text);

holder.text1=(TextView)vi.findViewById(R.id.text1);

Android Tutorial on Checking Internet Connection

2014-01-24T05:35:00.000-08:00

Android Tutorial on Checking Internet Connection

Many Android applications needs to connect to internet to complete the task.It is better to check internet connectivity status before making any HTTP Requests in your program to avoid http exceptions.Some of the most common uses for repeating alarms and background services is to schedule regular updates of application data from Internet resources, cache data, or execute long running downloads. But if you aren't connected to the Internet, or the connection is too slow to complete your download, why both waking the device to schedule the update at all?

Connectivity Manager

ConnectivityManager to is used to check that you're actually connected to the Internet, and if so, what type of connection is in place.Class that answers queries about the state of network connectivity. It also notifies applications when network connectivity changes. Get an instance of this class by calling Context.getSystemService(Context.CONNECTIVITY_SERVICE).

The primary responsibilities of this class are to:

Monitor network connections (Wi-Fi, GPRS, UMTS, etc.)
Send broadcast intents when network connectivity changes
Attempt to "fail over" to another network when connectivity to a network is lost
Provide an API that allows applications to query the coarse-grained or fine-grained state of the available networks

HttpURLConnection

HttpURLConnection which is also available in standard Java, is a general-purpose, lightweight HTTP client suitable for most applications.In the latest version HttpURLConnection supports the transparent response compression (via the header Accept-Encoding: gzip, Server Name Indication (extension of SSL and TLS) and a response cache.

Handler class

The Handler class can be used to register to a thread and provides a simple channel to send data to this thread.A Handler object registers itself with the thread in which it is created. For example, if you create a new instance of the Handler class in the onCreate() method of your activity, the resulting Handler object can be used to post data to the main thread.The data which can be posted via the Handler class can be an instance of the Message or the Runnable class.

This Demonstrative project is used to test whether network connectivity and internet connection are available.

1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_InternetConnectionCheck
Package name	in.ac.srmuniv.internetcheck
Activity name	InternetConnectionActivity
Layout xml name	main

2.Copy the code to the file main.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

</LinearLayout>

3.Copy the code in ConnectionDetector.java

package in.ac.srmuniv.internetcheck;

import java.io.IOException;

import java.net.HttpURLConnection;

import java.net.URL;

import java.util.ArrayList;

import java.util.List;

import android.content.Context;

import android.net.ConnectivityManager;

import android.net.NetworkInfo;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

public class ConnectionDetector {

private Context _context;

List<String> connections;

public ConnectionDetector(Context context) {

this._context = context;

connections=new ArrayList<String>();

}

public boolean isConnectingToInternet() {

boolean internetState=false;

ConnectivityManager connectivity = (ConnectivityManager) _context

.getSystemService(Context.CONNECTIVITY_SERVICE);

if (connectivity != null) {

NetworkInfo[] info = connectivity.getAllNetworkInfo();

if (info != null)

for (int i = 0; i < info.length; i++)

if (info[i].getState() == NetworkInfo.State.CONNECTED)

{

connections.add(info[i].getTypeName());

internetState=true;

}

return internetState;

}

List<String> getConnections()

{

return connections;

}

public boolean hasActiveInternetConnection() {

new Thread() {

public void run() {

Message msg = Message.obtain();

try {

HttpURLConnection urlc = (HttpURLConnection) (new URL(

"http://www.google.com").openConnection());

urlc.setRequestProperty("User-Agent", "Test");

urlc.setRequestProperty("Connection", "close");

urlc.setConnectTimeout(1500);

urlc.connect();

boolean status = urlc.getResponseCode() == 200;

Bundle b = new Bundle();

b.putBoolean("status", status);

msg.setData(b);

} catch (IOException e) {

}

messageHandler.sendMessage(msg);

}

}.start();

return status;

}

private static Handler messageHandler = new Handler() {

public void handleMessage(Message msg) {

super.handleMessage(msg);

status = msg.getData().getBoolean("status");

}

};

static boolean status;

}

4.Copy the code in InternetConnectionActivity.java. Activity.

package in.ac.srmuniv.internetcheck;

import java.util.ArrayList;

import in.ac.srmuniv.internetcheck.R;

import android.app.Activity;

import android.app.AlertDialog;

import android.content.Context;

import android.content.DialogInterface;

import android.os.Bundle;

public class InternetConnectionActivity extends Activity {

// flag for Internet connection status

private Boolean isInternetPresent = false;

private Boolean isConnectionPresent = false;

// Connection detector class

private ConnectionDetector cd;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// creating connection detector class instance

cd = new ConnectionDetector(getApplicationContext());

// get Internet status

isConnectionPresent = cd.isConnectingToInternet();

isInternetPresent = cd.hasActiveInternetConnection();

ArrayList<String> conn=(ArrayList<String>)cd.getConnections();

// check for Internet status

if (isInternetPresent) {

// Internet Connection is Present

// make HTTP requests

showAlertDialog(InternetConnectionActivity.this,

"Internet Connection", "You have internet connection:"+conn+" Available", true);

} else if (isConnectionPresent) {

// Internet connection is not present

// Ask user to connect to Internet

showAlertDialog(InternetConnectionActivity.this,

"No Internet Connection",

"You have "+conn+" Available", false);

} else {

// Internet connection is not present

// Ask user to connect to Internet

showAlertDialog(

InternetConnectionActivity.this,

"No Internet Connection",

"You don't have internet connection check for Mobile Data or WiFi is on.",

false);

}

public void showAlertDialog(Context context, String title, String message,

Boolean status) {

final Boolean stat = status;

AlertDialog alertDialog = new AlertDialog.Builder(context).create();

// Setting Dialog Title

alertDialog.setTitle(title);

// Setting Dialog Message

alertDialog.setMessage(message);

// Setting alert dialog icon

alertDialog.setIcon((status) ? R.drawable.success : R.drawable.fail);

// Setting OK Button

alertDialog.~~setButton~~("OK", new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

if (!stat)

finish();

}

});

// Showing Alert Message

alertDialog.show();

}

5.Modify the Androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.internetcheck"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk android:minSdkVersion="10" />

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

<application

android:icon="@drawable/icon"

android:label="@string/app_name" >

<activity

android:name=".InternetConnectionActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

6.Run the application in the emulator

Figure 1 Shows Dialog box showing Internet Connection Figure 2 Shows Dialog Box showing device with no internet connection WiFi or Mobile data is off

Figure 3 Shows Dialog Box showing device with no internet connection but WiFi or Mobile data is on

CODE EXPLANATION

This Demonstative application checks internet connection.When Activity is loaded it checks for two things, wheather Connectivity is available and what type of connectivity is available (WiFi or mobile) ,then it also checks if Active internet connection is available by pinging google.com website.

The following code in ConnectingToInternet() method tests the connectivity status and returns boolean value true if connectivity is available.NetworkInfo class helps to fetch what type of connection(WiFi or mobile) is activated.getConnections() method returns list of connections.

ConnectivityManager connectivity = (ConnectivityManager) _context

.getSystemService(Context.CONNECTIVITY_SERVICE);

if (connectivity != null) {

NetworkInfo[] info = connectivity.getAllNetworkInfo();

if (info != null)

for (int i = 0; i < info.length; i++)

if (info[i].getState() == NetworkInfo.State.CONNECTED) {

return true;

}

}
The following code in hasActiveInternetConnection() method tests the internet connection status and returns boolean value true if internet connectivity is available.

HttpURLConnection urlc = (HttpURLConnection) (new URL(

"http://www.google.com").openConnection());

urlc.setRequestProperty("User-Agent", "Test");

urlc.setRequestProperty("Connection", "close");

urlc.setConnectTimeout(1500);

urlc.connect();

boolean status = urlc.getResponseCode() == 200;
HttpURLConnection takes URL google.com to open connection and neccessary headers are set User-Agent is set to Test indicates it is a test connection.Connection header is set to close not keep-alive since we are oing to test for internet connectivity only and time out to 1500 ms.We take the status through response code 200 which ensures the mobile has active internet connection.
This demostative App also shows the usage of simple Thread and message Handler.HttpURLConnection should not be run in main thread.if the Thread doing backround task wants to send message value during its process it uses Message to send the values the message is packed in Bundle.The Handler class has callback method handleMessage(Message msg) which will be called when message is send.Here the status of internet connection is send through Handler to be used my main thread.
Message msg = Message.obtain();

Bundle b = new Bundle();
.....
.....

b.putBoolean("status", status);

msg.setData(b);

messageHandler.sendMessage(msg);

.....
.....

private static Handler messageHandler = new Handler() {

public void handleMessage(Message msg) {

super.handleMessage(msg);

status = msg.getData().getBoolean("status");

}

};

Android Animation Tutorial

2014-01-16T09:05:00.001-08:00

Android animation tutorial

There are three types of animation mechanisms in Android . The View Animation is simple and can handle many common requirements.

The View Animation system is the simplest of the three mechanisms. It lets you define properties of your Views that should be animated using a technique called tween animation. You implement the animation by specifying transformations on your View at the start and at the end of the animation. This can be done in XML resource files or programmatically. The downside of this mechanism is that it can only be applied to Views.

The Property Animation system is much more powerful that the View Animation system. It lets you animate essentially anything. The animations are highly customizable, you can specify the duration, the type of interpolation, the number of repeats and even (within limits) the frame rate of the animation. The Property Animation system should be your first choice for more complex animations.Android 3.0 introduced the Properties Animation API which allow to change object properties over a predefined time interval.The API allows to define for arbitrary object properties a start and end value and apply a time-based change to this attribute. This API can be applied on any Java object not only on Views.

The Drawable Animation gives you the most freedom in the sense that you can specify every single frame of the animation as a separate Drawable resource. It is akin to the more traditional animation in which images are shown one after another in quick succession. The downside of this approach is that every frame has to be specified separately. This can and up to be very tedious and time consuming.

Tween animation

An animation defined in XML that performs transitions such as rotating, fading, moving, and stretching on a graphic.

FILE LOCATION:

res/anim/filename.xml
The filename will be used as the resource ID.

COMPILED RESOURCE DATATYPE:

Resource pointer to an Animation.

RESOURCE REFERENCE:

In Java: R.anim.filename
In XML: @[package:]anim/filename

The file must have a single root element: either an <alpha>, <scale>, <translate>, <rotate>, or <set>element that holds a group (or groups) of other animation elements (even nested <set> elements).

Animation listeners

If you want to listen to animation events like start, end and repeat, your activity should implements AnimationListener. This step is optional. If you implement AnimationListener you will have to override following methods.

onAnimationStart – This will be triggered once the animation startedonAnimationEnd – This will be triggered once the animation is overonAnimationRepeat – This will be triggered if the animation repeats

Important XML animation attributes

When working with animations it is better to have through knowledge about some of the important XML attributes which create major differentiation in animation behavior. Following are the important attributes you must known about.

android:duration – Duration of the animation in which the animation should complete

android:startOffset – It is the waiting time before an animation starts. This property is mainly used to perform multiple animations in a sequential manner

android:interpolator – It is the rate of change in animation

android:fillAfter – This defines whether to apply the animation transformation after the animation completes or not. If it sets to false the element changes to its previous state after the animation. This attribute should be use with <set> node

android:repeatMode – This is useful when you want your animation to be repeat

android:repeatCount – This defines number of repetitions on animation. If you set this value to infinite then animation will repeat infinite times.

Following are the few animation schemes

1.Fade In 2.Fade Out 3. Cross Fading4. Blink5. Zoom In 6.Zoom Out 7.Rotate 8.Move 9.Slide Up 10.Slide Down 11.Bounce 12.Sequential Animation 13.Together Animation

Animation Types

Fade In
For fade in animation you can use <alpha> tag which defines alpha value. Fade in animation is nothing but increasing alpha value from 0 to 1.

fade_in.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:fillAfter="true" >

<alpha

android:duration="1000"

android:fromAlpha="0.0"

android:interpolator="@android:anim/accelerate_interpolator"

android:toAlpha="1.0" />

</set>

Fade_out

Fade out is exactly opposite to fade in, where we need to decrease the alpha value from 1 to 0

fade_out.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:fillAfter="true" >

<alpha

android:duration="1000"

android:fromAlpha="1.0"

android:interpolator="@android:anim/accelerate_interpolator"

android:toAlpha="0.0" />

</set>

Blink

Blink animation is animating fade out or fade in animation in repetitive fashion.

For this you will have to set android:repeatCount="infinite" attributes.

blink.xml

<?xml version="1.0" encoding="utf-8"?>

<alpha

android:duration="600"

android:fromAlpha="0.0"

android:interpolator="@android:anim/accelerate_interpolator"

android:repeatCount="infinite"

android:repeatMode="reverse"

android:toAlpha="1.0" />

</set>

Zoom_In

For zoom use <scale> tag. Use piviotX=50% and piviotY=50% to perform zoom from the center of the element. Also you need to use ,fromXScale, fromYScale attributes which defines scaling of the object. Keep these value lesser than toXScale, toYScale.This will set the pivot point to the centre of the animated view. Note how the pivot point coordinates are specified in percent. There are three different ways to specify the pivot point.
50% is the centre of the animated view (relative to view).50%p is the centre of the view’s parent (relative to parent).50 is 50 pixels from the top/left of the animated view (absolute).
When specifying the absolute value of the pivot you may not use units, such as dp, sp, ptor mm. If you want to use those units then you have to specify the pivot programmatically.

zoom_in.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:fillAfter="true" >

<scale

xmlns:android="http://schemas.android.com/apk/res/android"

android:duration="1000"

android:fromXScale="1"

android:fromYScale="1"

android:pivotX="50%"

android:pivotY="50%"

android:toXScale="3"

android:toYScale="3" >

</scale>

</set>

Zoom_out

Zoom out animation is same as zoom in but toXScale, toYScale values are lesser thanfromXScale, fromYScale

zoom_out.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:fillAfter="true" >

<scale

xmlns:android="http://schemas.android.com/apk/res/android"

android:duration="1000"

android:fromXScale="1.0"

android:fromYScale="1.0"

android:pivotX="50%"

android:pivotY="50%"

android:toXScale="0.5"

android:toYScale="0.5" >

</scale>

</set>

Rotate

The rotate element lets you rotate a view around a pivot point. The rotation is in the plane of the screen only. The View Animation system does not allow 3d rotations. These can only be done using the Property Animation system.The values of fromDegrees and toDegrees specify the rotation angle at the start and end of the animation. The specifications say that you can specify the angle as a floating point number. In most cases,however, the angles you specify here will be integers.

The pivotX and pivotY attributes specify the centre of the rotation. You can specify the values exaclty in the same way as the pivotX and pivotY of the scale animation.

rotate.xml

<?xml version="1.0" encoding="utf-8"?>

<rotate

android:duration="600"

android:fromDegrees="0"

android:interpolator="@android:anim/cycle_interpolator"

android:pivotX="50%"

android:pivotY="50%"

android:repeatCount="infinite"

android:repeatMode="restart"

android:toDegrees="360" />

</set>

Move

In order to change position of object use <translate> tag. The values fromXDelta and fromYDelta specify the position of the view at the start of the animation, whereas toXDelta and toYDelta specify the position of the view at the end of the animation.

As with the pivot of the scale animation the start and end locations of the view can be specified in pixels, in percent of the width and height of the animated view by appending% or in percent of the width and height of the parent view by appending %p.

move.xml

<?xml version="1.0" encoding="utf-8"?>

<set

xmlns:android="http://schemas.android.com/apk/res/android"

android:fillAfter="true"

android:interpolator="@android:anim/linear_interpolator" >

<translate

android:duration="800"

android:fromXDelta="0%p"

android:toXDelta="75%p" />

</set>

Slide Up

Sliding animation uses <scale> tag only. Slide up can be achieved by setting android:fromYScale=”1.0″ and android:toYScale=”0.0″

slide_up.xml

<?xml version="1.0" encoding="utf-8"?>

    <set

        xmlns:android="http://schemas.android.com/apk/res/android"

        android:fillAfter="true" >

        <scale

            android:duration="500"

            android:fromXScale="1.0"

            android:fromYScale="1.0"

            android:interpolator="@android:anim/linear_interpolator"

            android:toXScale="1.0"

            android:toYScale="0.0" />
    </set>

Slide Down

Slide down is exactly opposite to slide down animation. Just interchange android:fromYScale and android:toYScale values.

slide_down.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:fillAfter="true" >

<scale

android:duration="500"

android:fromXScale="1.0"

android:fromYScale="0.0"

android:interpolator="@android:anim/linear_interpolator"

android:toXScale="1.0"

android:toYScale="1.0" />

</set>

Bounce

Bounce is just an animation effect where animation ends in bouncing fashion. For this set android:interpolator value to @android:anim/bounce_interpolator. This bounce can be used with any kind animation. Following slide down example uses bounce effect.

bounce.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:fillAfter="true"

android:interpolator="@android:anim/bounce_interpolator" >

<scale

android:duration="500"

android:fromXScale="1.0"

android:fromYScale="0.0"

android:toXScale="1.0"

android:toYScale="1.0" />

</set>

Combining Animation Types

Each of the animation types above have good uses on their own but the real power of animations lies in combining multiple animations into one. The set XML element lets you create animations that are made from multiple effects, either simultaneously or one after the other. The set element allows to combine the other animation types into groups. Let’s have a look at an example.This animation combines an alpha, a rotate and a scale animation into a single animation. The combined animation makes the view rotate, scale down to a point and fade out at the same time.Note that we have specified the interpolator of the animation set and also set the shareInterpolator attribute to true. This means that all the elements that are inside the animation set use the same interpolator. It is also possible to specify the interpolator of each individual animation within the set separately.

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:duration="1000"

android:fillAfter="false"

android:interpolator="@android:anim/accelerate_interpolator"

android:shareInterpolator="true" >

<alpha

android:fromAlpha="1.0"

android:toAlpha="0.0" />

<rotate

android:fromDegrees="0"

android:pivotX="50%"

android:pivotY="50%"

android:toDegrees="360" />

<scale

android:fillAfter="true"

android:fromXScale="1.0"

android:fromYScale="1.0"

android:pivotX="50%"

android:pivotY="50%"

android:toXScale="0.0"

android:toYScale="0.0" />

</set>

Playing a Sequence of Animations

We can also combine animations to produce a sequence of different effects. Maybe we want to first scale vertically and then horizontally. The following XML code uses thestartOffset attribute and does exactly that.The startOffset attribute specifies after which time, from the start of the complete animation, the specific animation should be played.

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:interpolator="@android:anim/linear_interpolator" >

<rotate

android:duration="1000"

android:fromDegrees="0"

android:interpolator="@android:anim/cycle_interpolator"

android:pivotX="50%"

android:pivotY="50%"

android:repeatCount="2"

android:repeatMode="restart"

android:startOffset="100"

android:toDegrees="360" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromXDelta="0%p"

android:startOffset="1100"

android:toXDelta="75%p" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromYDelta="0%p"

android:startOffset="2100"

android:toYDelta="70%p" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromXDelta="0%p"

android:startOffset="3100"

android:toXDelta="-75%p" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromYDelta="0%p"

android:startOffset="4100"

android:toYDelta="-70%p" />

<scale

xmlns:android="http://schemas.android.com/apk/res/android"

android:duration="1000"

android:fromXScale="1"

android:fromYScale="1"

android:pivotX="50%"

android:pivotY="50%"

android:startOffset="5100"

android:toXScale="2"

android:toYScale="2" >

</scale>

<scale

xmlns:android="http://schemas.android.com/apk/res/android"

android:duration="1000"

android:fromXScale="1.0"

android:fromYScale="1.0"

android:pivotX="50%"

android:pivotY="50%"

android:startOffset="6100"

android:toXScale="0.5"

android:toYScale="0.5" >

</scale>

<alpha

android:duration="1000"

android:fromAlpha="1.0"

android:interpolator="@android:anim/accelerate_interpolator"

android:startOffset="7100"

android:toAlpha="0.1" />

</set>

In the example above the first rotate animation the duration has been set to 1000ms with inital offset of 100ms. After the first rotate animation has finished we want to start the second animation translate. This second animation should, therefore, have a startOffset of 2100.Rotate animation would have consumed 2100 ms since repeat count is one two times rotation will happen. Translate also plays for 1000ms after which the next animation starts.you need to claculate and appened the startOffset timing accordingly.

There are several things to note about the example above. First of all, when playing animations in sequence, you should always set shareInterpolator to false and not set a duration in the surrounding animation set. Instead you should specify each interpolator and duration separately. The View Animation system will automatically figure out the total duration of the animation for you.

ViewFlipper

A ViewFlipper is a simple ViewAnimator that will animate between two or more views that have been added to it. Only one child is shown at a time. If requested, can automatically flip between each child at a regular interval.

A ViewFlipper can be used to slide views in and out of the user’s current view port .These Views slides with given appropriate Animation.

1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_AndroidAnimationTutorial
Package name	in.ac.srmuniv.animation
Activity name	MainActivity
Layout xml name	main

2.Copy the code to the file main.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dp"

android:gravity="center"

android:text="SRM University Photos"

android:textColor="#000099"

android:textSize="20dp" />

<ViewFlipper

android:id="@+id/view_flipper"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:layout_margin="6dip" >

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center"

android:orientation="vertical" >

<TextView

android:id="@+id/txtView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="15dp"

android:text="SRM HOTEL"

android:textColor="#191975"

android:textSize="25dp"

android:textStyle="bold" >

</TextView>

<ImageView

android:id="@+id/imageView1"

android:layout_width="450dp"

android:layout_height="450dp"

android:layout_marginTop="15dp"

android:src="@drawable/srmimage1" />

</LinearLayout>

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center"

android:orientation="vertical" >

<TextView

android:id="@+id/txtView2"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="15dp"

android:text="SRM HOSTELS"

android:textColor="#191975"

android:textSize="25dp"

android:textStyle="bold" >

</TextView>

<ImageView

android:id="@+id/imageView2"

android:layout_width="450dp"

android:layout_height="450dp"

android:layout_marginTop="15dp"

android:src="@drawable/srmimage2" />

</LinearLayout>

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center"

android:orientation="vertical" >

<TextView

android:id="@+id/txtView3"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="15dp"

android:text="TECH-PARK BUILDING"

android:textColor="#191975"

android:textSize="25dp"

android:textStyle="bold" >

</TextView>

<ImageView

android:id="@+id/imageView3"

android:layout_width="450dp"

android:layout_height="450dp"

android:layout_marginTop="15dp"

android:src="@drawable/srmimage3" />

</LinearLayout>

</ViewFlipper>

</LinearLayout>

3.Create anim folder in res add the following xml files

a) animation.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:interpolator="@android:anim/linear_interpolator" >

<rotate

android:duration="1000"

android:fromDegrees="0"

android:interpolator="@android:anim/cycle_interpolator"

android:pivotX="50%"

android:pivotY="50%"

android:repeatCount="1"

android:repeatMode="restart"

android:startOffset="100"

android:toDegrees="360" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromXDelta="0%p"

android:startOffset="2100"

android:toXDelta="75%p" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromYDelta="0%p"

android:startOffset="3100"

android:toYDelta="70%p" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromXDelta="0%p"

android:startOffset="4100"

android:toXDelta="-75%p" />

<translate

android:duration="1000"

android:fillAfter="true"

android:fromYDelta="0%p"

android:startOffset="5100"

android:toYDelta="-70%p" />

<scale

xmlns:android="http://schemas.android.com/apk/res/android"

android:duration="1000"

android:fromXScale="1"

android:fromYScale="1"

android:pivotX="50%"

android:pivotY="50%"

android:startOffset="6100"

android:toXScale="2"

android:toYScale="2" >

</scale>

<scale

xmlns:android="http://schemas.android.com/apk/res/android"

android:duration="1000"

android:fromXScale="1.0"

android:fromYScale="1.0"

android:pivotX="50%"

android:pivotY="50%"

android:startOffset="7100"

android:toXScale="0.5"

android:toYScale="0.5" >

</scale>

<alpha

android:duration="1000"

android:fromAlpha="1.0"

android:interpolator="@android:anim/accelerate_interpolator"

android:startOffset="8100"

android:toAlpha="0.1" />

</set>

b.in_from_left.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:shareInterpolator="false">

<translate

android:fromXDelta="-100%" android:toXDelta="0%"

android:fromYDelta="0%" android:toYDelta="0%"

android:duration="1000" />

</set>

c.in_to_right.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:shareInterpolator="false">

<translate

android:fromXDelta="0%" android:toXDelta="-100%"

android:fromYDelta="0%" android:toYDelta="0%"

android:duration="1000" />

</set>

d.out_to_left.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:shareInterpolator="false">

<translate

android:fromXDelta="0%" android:toXDelta="100%"

android:fromYDelta="0%" android:toYDelta="0%"

android:duration="1000" />

</set>

e.out_from_right.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"

android:shareInterpolator="false">

<translate

android:fromXDelta="-100%" android:toXDelta="0%"

android:fromYDelta="0%" android:toYDelta="0%"

android:duration="1000" />

</set>

4.Copy the code in MainActivity.java. Activity.

package in.ac.srmuniv.animation;

import in.ac.srmuniv.animation.R;

import android.app.Activity;

import android.os.Bundle;

import android.util.Log;

import android.view.MotionEvent;

import android.view.View;

import android.view.animation.Animation;

import android.view.animation.Animation.AnimationListener;

import android.view.animation.AnimationUtils;

import android.widget.TextView;

import android.widget.Toast;

import android.widget.ViewFlipper;

public class MainActivity extends Activity implements AnimationListener {

private ViewFlipper viewFlipper;

TextView txtView;

TextView txtView1;

TextView txtView2;

private Animation animSequence;

private float lastX;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

viewFlipper = (ViewFlipper) findViewById(R.id.view_flipper);

txtView = (TextView) findViewById(R.id.txtView1);

animSequence = AnimationUtils.loadAnimation(this, R.anim.animation);

animSequence.setAnimationListener(this);

}

// Method to handle touch event like left to right swap and right to left

// swap

public boolean onTouchEvent(MotionEvent touchevent) {

switch (touchevent.getAction()) {

// when user first touches the screen to swap

case MotionEvent.ACTION_DOWN: {

lastX = touchevent.getX();

break;

}

case MotionEvent.ACTION_UP: {

float currentX = touchevent.getX();

// if left to right swipe on screen

if (lastX < currentX) {

// If no more View/Child to flip

if (viewFlipper.getDisplayedChild() == 0)

break;

// set the required Animation type to ViewFlipper

// The Next screen will come in form Left and current Screen

// will go OUT from Right

viewFlipper.setInAnimation(this, R.anim.in_from_left);

viewFlipper.setOutAnimation(this, R.anim.out_to_right);

// Show the next Screen

// viewFlipper.getChildAt(viewFlipper.getDisplayedChild()).startAnimation(animFadeIn);

viewFlipper.showNext();

View v = viewFlipper

.getChildAt(viewFlipper.getDisplayedChild());

v.startAnimation(animSequence);

}

// if right to left swipe on screen

if (lastX > currentX) {

if (viewFlipper.getDisplayedChild() == 1)

break;

// set the required Animation type to ViewFlipper

// The Next screen will come in form Right and current Screen

// will go OUT from Left

viewFlipper.setInAnimation(this, R.anim.in_from_right);

viewFlipper.setOutAnimation(this, R.anim.out_to_left);

// Show The Previous Screen

viewFlipper.showPrevious();

viewFlipper.getChildAt(viewFlipper.getDisplayedChild())

.startAnimation(animSequence);

}

break;

}

return false;

}

@Override

public void onAnimationEnd(Animation arg0) {

Toast.makeText(getApplicationContext(), "Animation Stopped",

Toast.LENGTH_LONG).show();

}

@Override

public void onAnimationRepeat(Animation animation) {

Toast.makeText(getApplicationContext(), "Animation Repeated",

Toast.LENGTH_SHORT).show();

}

@Override

public void onAnimationStart(Animation animation) {

Toast.makeText(getApplicationContext(), "Animation Started",

Toast.LENGTH_SHORT).show();

}

5.No need to modify Androidmanifest.xml

6.Run the application in the emulator/device.

Figure 1 Shows rotate animation              Figure 2 Shows translate animation

           Figure 3 Shows scale animation                              Figure 4 Shows fade animation

CODE EXPLANATION


              In this Application we can see main.xml,the layout for MainActivity 

 containing ViewFlipper which itself is a containter consisting of three child 

elements.In the anim folder four xml translate animation files are needed to perform 

image translation.The first child element of viewflipper is displayed,

When the user swipes the screen 

 boolean onTouchEvent(MotionEvent touchevent) is called ACTION_DOWN 

 recognizes when user first touches the screen to swipe and ACTION_UP 

is called when user releases the swipe.The lastX and currentX coordinates 

are calculated to decide wheather swipe is from left to right or right to left.

If lastX < currentX then following code sets the required Animation type

 to ViewFlipper to translate.The Next screen will come in form Left and 

current Screen will go OUT from Right.
      viewFlipper.setInAnimation(this, R.anim.in_from_left);

       viewFlipper.setOutAnimation(this, R.anim.out_to_right);


      viewFlipper.showNext();



will Show the next Screen simlarly lastX > currentX The Next screen will come in form Right and current Screen will go OUT from Left.



          viewFlipper.setInAnimation(this, R.anim.in_from_right);



          viewFlipper.setOutAnimation(this, R.anim.out_to_left);



          viewFlipper.showPrevious();

will show the Previous Screen.

 The selected child view of viewflipper is identified and the view is set for animation which include rotation with repeat for one more time translation for four times ,zoom in and zoom out then finally followed by fade effect.


                                 View v = viewFlipper  getChildAt(viewFlipper.getDisplayedChild());



                                  v.startAnimation(animSequence);

Android JSON based Web Services tutorial

2013-12-20T04:31:00.000-08:00

ANDROID JSON BASED WEB SERVICES TUTORIAL

JSON or JavaScript Object Notation is a lightweight text-based open standard designed for human-readable data interchange. The JSON format was originally specified by Douglas Crockford, and is described in RFC 4627. The official Internet media type for JSON is application/json. The JSON filename extension is .json.

JSON syntax is similar to the JavaScript syntax of java script objects, it includes the following:
Data is represented in name/value pairs
Curly braces hold objects and each name is followed by ':'(colon), the name/value pairs are separated by , (comma).
Square brackets hold arrays and values are separated by ,(comma).

following provides a simple example:

{
"staff": [
{
"staff_Id":"1",
"dept": "IT",
"specialization": "Computer Science",
"name": "K.Navin"
},
{
"staff_Id":"2",
"dept": "CSE",
"specialization": "Computer Science",
"name": "V.Joseph Raymond"
}, ]
}
Android JSON Parsers
Android provides four differnet classes to manipulate JSON data. These classes areJSONArray,JSONObject,JSONStringer and JSONTokenizer.

JSON - Elements

An JSON file consist of many components. Here is the table defining the compoents of an JSON file and their description:

Sl.No	Component & description
1	Array([) In a JSON file , square bracket ([) represents a JSON array
2	Objects({) In a JSON file, curly bracket ({) represents a JSON object
3	Key A JSON object contains a key that is just a string. Pairs of key/value make up a JSON object
4	Value Each key has a value that could be string , integer or double e.t.c

JSON – Parsing

For parsing a JSON object, we will create an object of class JSONObject and specify a string containing JSON data to it. Its syntax is:

String in;

JSONObject reader = new JSONObject(in);

The last step is to parse the JSON. An JSON file consist of different object with different key/value pair e.t.c. So JSONObject has a seperate function for parsing each of the component of JSON file. Its syntax is given below:

ArrayList<HashMap<String, String>>staffList = new ArrayList<HashMap<String, String>>();

// Getting Array of staff details

JSONObject saffs = json.getJSONArray(“staff”);

// looping through All staff details

for(int i = 0; i < staffs.length(); i++){

JSONObject c = staffs.getJSONObject(i);

// Storing each json item in variable

Integer id = c.getString(“staff_id”);

String name = c.getString(“dept”);

String email = c.getString(“specialization”);

String address = c.getString(“name”);

// creating new HashMap

HashMap<String, String> map = new HashMap<String, String>();

// adding each child node to HashMap key => value

map.put(“STAFF_ID”, id);

map.put(“NAME”, name);

map.put(“DEPARTMENT”, email);

map.put(“SPECIALIZATION”, mobile);

// adding HashList to ArrayList

staffList.add(map);

}

The method getJSONObject returns the JSON object. The method getString returns the string value of the specified key.

Apart from the these methods , there are other methods provided by this class for better parsing JSON files. These methods are listed below:

Sr.No	Method & description
1	get(String name) This method just Returns the value but in the form of Object type
2	getBoolean(String name) This method returns the boolean value specified by the key
3	getDouble(String name) This method returns the double value specified by the key
4	getInt(String name) This method returns the integer value specified by the key
5	getLong(String name) This method returns the long value specified by the key
6	length() This method returns the number of name/value mappings in this object..
7	names() This method returns an array containing the string names in this object.

The Demonstrative project uses the JSON services from the following url to fetch currency rate between British pound,Indian rupees,U.S dollor and euro .http://www.rate-exchange.appspot.com

1.Create Android project with details as listed in the table below.

Property name	Property value
Project name	SRM_CurrencyConvertorJSON
Package name	in.ac.srmuniv.currencyconvertorjson
Activity name	MainActivity
Layout xml name	main.xml

2.Copy the code to the file gridview.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:gravity="center_horizontal"

android:text="@string/app_name"

android:textSize="@dimen/headsize" />

<TableLayout

android:id="@+id/TableLayout1"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="50dp" >

<TableRow

android:id="@+id/tableRow1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginEnd="10dp"

android:layout_marginLeft="10dp" >

<Spinner

android:id="@+id/spinner1"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_weight="1"

android:drawSelectorOnTop="true"

android:prompt="@string/select_Category" />

</TableRow>

<TableRow

android:id="@+id/tableRow2"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginEnd="10dp"

android:layout_marginLeft="10dp" >

<TextView

android:id="@+id/textView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:gravity="center_horizontal"

android:text="@string/to"

android:textAppearance="?android:attr/textAppearanceMedium" />

</TableRow>

<TableRow

android:id="@+id/tableRow3"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginEnd="10dp"

android:layout_marginLeft="10dp"

android:gravity="center_horizontal" >

<Spinner

android:id="@+id/spinner2"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_weight="1" />

</TableRow>

<TableRow

android:id="@+id/tableRow6"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginEnd="10dp"

android:layout_marginLeft="10dp" >

</TableRow>

<TableRow

android:id="@+id/tableRow3"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginEnd="10dp"

android:layout_marginLeft="10dp" >

<TextView

android:id="@+id/textView3"

style="@style/CodeFont"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="Enter Value of money to be converted" />

</TableRow>

</TableLayout>

<LinearLayout

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:orientation="horizontal" >

<EditText

android:id="@+id/editText1"

android:layout_width="150dp"

android:layout_height="wrap_content"

android:layout_marginEnd="40dp"

android:layout_marginLeft="10dp"

android:inputType="numberDecimal"

android:maxLength="4" />

<Button

android:id="@+id/button1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/convert" />

</LinearLayout>

<LinearLayout

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:orientation="vertical" >

<TextView

android:id="@+id/textView2"

style="@style/CodeFont"

android:layout_gravity="center_horizontal"

android:gravity="center_horizontal"

android:text="Converted"

android:textAppearance="?android:attr/textAppearanceLarge"

android:textSize="@dimen/out" />

</LinearLayout>

3.Copy the code to the file row.xml in res/layout folder

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="vertical"

android:padding="1dip" >

<ImageView

android:id="@+id/image"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:src="@drawable/ic_launcher" />

<TextView

android:id="@+id/country"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginLeft="5dip"

android:layout_toRightOf="@+id/image"

android:padding="2dip"

android:textColor="@drawable/red"

android:textStyle="bold" />

<TextView

android:id="@+id/currency"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_below="@+id/country"

android:layout_marginLeft="5dip"

android:layout_toRightOf="@+id/image"

android:padding="2dip"

android:textColor="@drawable/darkgrey" />

</RelativeLayout>

4.Copy the code in MainActivity.java. Activity.

package in.ac.srmuniv.currencyconvertorjson;

import in.ac.srmuniv.currencyconvertorjson.R;

import android.app.Activity;

import android.app.ProgressDialog;

import android.content.Context;

import android.os.AsyncTask;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemSelectedListener;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.EditText;

import android.widget.ImageView;

import android.widget.Spinner;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends Activity {

String[] country = { "British", "European", "American", "Indian" };

String[] currency = { "Pounds ", "Euro", "Dollor", "Rupee" };

String[] currency_abr = { "GBP", "EUR", "USD", "INR" };

String to_curr, from_curr;

int arr_images[] = { R.drawable.pound, R.drawable.euro, R.drawable.dollor,

R.drawable.rupee };

TextView converted;

Spinner from_currency;

Spinner to_currency;

EditText input;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

to_curr = "INR";

from_curr = "USD";

setContentView(R.layout.activity_main);

converted = (TextView) findViewById(R.id.textView2);

input = (EditText) findViewById(R.id.editText1);

converted.setText("");

from_currency = (Spinner) findViewById(R.id.spinner1);

from_currency.setAdapter(new MyAdapter(MainActivity.this, R.layout.row,

country));

from_currency.setSelection(2);

to_currency = (Spinner) findViewById(R.id.spinner2);

to_currency.setAdapter(new MyAdapter(MainActivity.this, R.layout.row,

country));

to_currency.setSelection(3);

from_currency.setOnItemSelectedListener(new OnItemSelectedListener() {

public void onItemSelected(AdapterView<?> parentView, View v,

int position, long id) {

Toast.makeText(getApplicationContext(),

"" + currency_abr[position], Toast.LENGTH_LONG).show();

converted.setHint(currency[position]);

from_curr = currency_abr[position];

}

public void onNothingSelected(AdapterView<?> parentView) {

// your code here

}

});

to_currency.setOnItemSelectedListener(new OnItemSelectedListener() {

public void onItemSelected(AdapterView<?> parentView, View v,

int position, long id) {

Toast.makeText(getApplicationContext(),

"" + currency_abr[position], Toast.LENGTH_LONG).show();

converted.setHint(currency[position]);

to_curr = currency_abr[position];

}

public void onNothingSelected(AdapterView<?> parentView) {

// your code here

}

});

Button button = (Button) findViewById(R.id.button1);

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

new DownloadData().execute(to_curr, from_curr, input.getText()

.toString());

}

});

converted = (TextView) findViewById(R.id.textView2);

}

class DownloadData extends AsyncTask<String, String, Double> {

ProgressDialog pd = null;

@Override

protected void onPreExecute() {

super.onPreExecute();

pd = new ProgressDialog(MainActivity.this);

pd.setTitle("Converting...");

pd.setMessage("Please wait...");

pd.setCancelable(false);

pd.show();

}

@Override

protected Double doInBackground(String... params) {

String to_curr = params[0];

String from_curr = params[1];

String value = params[2];

// Creating JSON Parser instance

JSONParser jParser = new JSONParser();

// getting JSON string from URL

jParser.getJSONFromUrl("http://www.currency-api.appspot.com /api/"+from_curr+"/"+ to_curr +".json");

/*
jParser.getJSONFromUrl("http://www.rate-exchange.appspot.com/currency?from="
+ from_curr + "&to=" + to_curr + "&q=" + value);not supported now

* JSONObject json = jParser

* .getJSONFromUrl("http://www.google.com/ig/calculator?hl=en&q=" +

* value + from_curr + "=" + to_curr + "?"); //Google stopped

* service from Nov 1 2013

double theResult = jParser.getResult();

return theResult;

}

@Override

protected void onPostExecute(Double theResult) {

super.onPostExecute(theResult);

pd.dismiss();

* double x; try { x = Double.parseDouble(theResult); } catch

* (NumberFormatException e) { // TODO Auto-generated catch block x

* = 1; input.setText(""); }

converted.setText(theResult.toString());

}

public class MyAdapter extends ArrayAdapter<String> {

public MyAdapter(Context context, int textViewResourceId,

String[] objects) {

super(context, textViewResourceId, objects);

}

@Override

public View getDropDownView(int position, View convertView,

ViewGroup parent) {

return getCustomView(position, convertView, parent);

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

return getCustomView(position, convertView, parent);

}

public View getCustomView(int position, View convertView,

ViewGroup parent) {

LayoutInflater inflater = getLayoutInflater();

View row = inflater.inflate(R.layout.row, parent, false);

TextView label = (TextView) row.findViewById(R.id.country);

label.setText(country[position]);

TextView sub = (TextView) row.findViewById(R.id.currency);

sub.setText(currency[position]);

ImageView icon = (ImageView) row.findViewById(R.id.image);

icon.setImageResource(arr_images[position]);

return row;

}

5.Create a class JSONParser.java copy the follwwing code

package in.ac.srmuniv.currencyconvertorjson;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.UnsupportedEncodingException;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.methods.HttpGet;

//import org.apache.http.client.methods.HttpPost;

import org.apache.http.impl.client.DefaultHttpClient;

import org.json.JSONException;

import org.json.JSONObject;

import android.util.Log;

public class JSONParser {

static InputStream is = null;

JSONObject jObj = null;

// constructor

public JSONParser() {

}

public void getJSONFromUrl(String url) {

String json = "";

// Making HTTP request

try {

// defaultHttpClient

DefaultHttpClient httpClient = new DefaultHttpClient();

HttpGet httpGet = new HttpGet(url);

// HttpPost httpPost = new HttpPost(url);// For google currency convertor now depricated

HttpResponse httpResponse = httpClient.execute(httpGet);

HttpEntity httpEntity = httpResponse.getEntity();

is = httpEntity.getContent();

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

} catch (ClientProtocolException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

try {

BufferedReader reader = new BufferedReader(new InputStreamReader(

is, "iso-8859-1"), 8);

StringBuilder sb = new StringBuilder();

String line = null;

while ((line = reader.readLine()) != null) {

sb.append(line + "\n");

}

json = sb.toString();

Log.d("JSON result", json);

} catch (Exception e) {

Log.e("Buffer Error", "Error converting result " + e.toString());

}

// try parse the string to a JSON object

try {

jObj = new JSONObject(json);

} catch (JSONException e) {

Log.e("JSON Parser", "Error parsing data " + e.toString());

}

double getResult() {

double theResult = 0.0;

        try {

             //theResult = jObj.getDouble("v");
            theResult = jObj.getDouble("rate");

System.out.println(theResult);

}

catch (JSONException e) {

e.printStackTrace();

} catch (Exception e) {

e.printStackTrace();

}

return theResult;

}

4.Modify Androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="in.ac.srmuniv.currencyconvertorjson"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="14"

android:targetSdkVersion="17" />

<uses-permission android:name="android.permission.INTERNET" />

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/MyTheme" >

<activity

android:name=".MainActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

6.Copy the code to the file string.xml in res/values folder

<?xml version="1.0" encoding="utf-8"?>

<string name="app_name">SRM_CurrencyConvertorJSON</string>

<string name="action_settings">Settings</string>

<string name="hello_world">Hello world!</string>

<drawable name="white">#ffffff</drawable>

<string name="select_Category">Select Category</string>

<string name="convert">Convert</string>

</resources>

7.Copy the code to the file dimens.xml in res/values folder

</resources>

8.Copy the code to the file styles.xml in res/layout folder

<!--

Base application theme, dependent on API level. This theme is replaced

by AppBaseTheme from res/values-vXX/styles.xml on newer devices.

-->

<!--

Theme customizations available in newer API levels can go in

res/values-vXX/styles.xml, while customizations related to

backward-compatibility can go here.

-->

</style>

</style>

<item name="android:windowTitleBackgroundStyle">@style/AppTheme</item>

</style>

<item name="android:windowBackground">@color/bk</item>

<item name="android:listViewStyle">@style/MySpinnerView</item>

</style>

<item name="android:spinnersShown">@drawable/euro</item>

</style>

<item name="android:layout_width">wrap_content</item>

<item name="android:layout_height">fill_parent</item>

<item name="android:typeface">monospace</item>

</style>

</resources>
9.Run the device/emulator with internet connection available

Fig 1 Shows the JSON based currency convertor app taking currency rate from www.rate-exchange.appspot.com a google appengine based service

CODE EXPLANATION
The currency convertor app has Mainactivity which contains appropriate UI.User can select currencies through spinners and value entered through editText.The values are appended to URL of json based webservice.MainActivity uses AsyncTask for making webservice request and fetching result.

Figure 2 Shows the rate -exchange google appengine based json webservice

JSONParser class uses HttpClient class with HttpGet method to send values of from_currency ,to_currency and the amount of value to be converted.

try {

// defaultHttpClient

DefaultHttpClient httpClient = new DefaultHttpClient();

HttpGet httpGet = new HttpGet(url);

// HttpPost httpPost = new HttpPost(url);// For google currency

// convertor now depricated

HttpResponse httpResponse = httpClient.execute(httpGet);

HttpEntity httpEntity = httpResponse.getEntity();

is = httpEntity.getContent();

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

} catch (ClientProtocolException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}
The response received from http://www.rate-exchange.appspot.com is stored in String and passed as argument to the constructor of JSONObject.The following is the received json object for the get request

{"to": "INR", "rate": 61.491999999999997, "from": "USD", "v": 614.91999999999996}

// try parse the string to a JSON object

try {

jObj = new JSONObject(json);

} catch (JSONException e) {

Log.e("JSON Parser", "Error parsing data " + e.toString());

}

.....
.....
JSONObject jObj contains various attributes but we are concerned with the attribute "v" which contains the converted rate multiplied with value .The method getDouble returns the double value for the specified key "v".

try {

theResult = jObj.getDouble("v");

System.out.println(theResult);

}

catch (JSONException e) {

e.printStackTrace();

} catch (Exception e) {

e.printStackTrace();

}