Tech Talk - Java

Java Design Patterns: Singleton Design Pattern

2012-10-08T21:44:00.001-04:00

Java Design Patterns: Singleton Design Pattern

While searching on the net, I come across this good video tutorial, so posting it here. Not created by me.

JAVA Design Patterns: Difference between Builder, Factory, and Abstract Factory Patterns

2012-10-08T21:19:00.005-04:00

JAVA Design Patterns: Difference between Builder, Factory, and Abstract Factory Patterns

While searching on the net, I come across this good video tutorial, so posting it here. Not created by me.

Change the background, text color for custom list view on focus and click

2012-03-14T19:00:00.000-04:00

Change the background, text color for custom list view on focus and click

In this tutorial we will see how to change the background color on the custom list item, how to change the text style of text view etc.

We will use the same example which we have created in "How to create custom list view in android application" blog.

Once you done with the above custom list creation follow the below steps to achieve this -

Create a highlight.png file and put that in drawable folder.
Create the selector for list item background, text 1 color, and text2 color as shown below under the drawable folder -

listselector.xml -

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

< item android:state_focused="true"

android:drawable="@drawable/highlight" / >

< item android:state_pressed="true"

android:drawable="@drawable/highlight" / >

< item android:state_selected="true"

android:drawable="@drawable/highlight" / >

< /selector>

listitemline1_selector.xml -

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

< item android:state_focused="true"

android:color="#0e0c0a"/ >

< item android:state_pressed="true" android:color="#0e0c0a" / >

< item android:state_selected="true"

android:color="#0e0c0a" / >

< item android:color="#b48f53" / >

< /selector >

listitemline2_selector.xml -

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

<item android:state_focused="true"

android:color="#0e0c0a"/>

<item android:state_selected="true"

android:color="#0e0c0a"/>

selector>

Now we need to assign these selector to individual list item and text views created on the hybridlist.xml file as shown below -

hybridlist.xml -

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

< LinearLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center_vertical"

android:descendantFocusability="blocksDescendants"

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

< LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="vertical"

android:background="@drawable/listselector"

android:layout_weight="1" >

< TextView

android:id="@+id/text1"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textSize="15sp"

android:textStyle="bold"

android:textColor="@drawable/listitemline1_selector" / >

< TextView

android:id="@+id/text2"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textSize="11sp"

android:textColor="@drawable/listitemline2_selector" / >

< / LinearLayout>

Now run the application and you will see the same output as shown above. Same kind of selector you can apply to any view like Button, ImageView, Spinner etc.

Create your own customized spinner control with icon and text

2012-03-13T23:52:00.000-04:00

How to create your own customized spinner control with icon and text

In this tutorial we will see how to create your own customized spinner view. In real life application, your UI designer will ask you to put some icon, with text having background etc. So to achieve this, you will need to create your own spinner view.

To achieve this, you will need need to place some icons in your drawable folder - motorola.png, google.png, microsoft.png, apple.png, yahoo.png, samsung.png.

First step to create an android project. I created with the "CustomerSpinnerDemo" and the package is "com.customspinnerdemo".
Copy the above mentioned images into res/drawable folder.
Create the string.xml file with the below content -

string.xml

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

<string name="hello">CustomSpinner Demo</string>

<string name="prompt">Choose your selection</string>

<string name="app_name">CustomSpinner Demo</string>

<drawable name="white">#ffffff</drawable>

<string name="select_Category">Select Category</string>

</resources>

Change the main.xml as follows -

<?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:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/hello"

<Spinner

android:id="@+id/spinner"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:drawSelectorOnTop="true"

android:prompt="@string/prompt"

</LinearLayout>

Create the row.xml as below under the 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="3dip"

<ImageView

android:id="@+id/image"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

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

<TextView

android:layout_toRightOf="@+id/image"

android:padding="3dip"

android:layout_marginTop="2dip"

android:textColor="@drawable/red"

android:textStyle="bold"

android:id="@+id/company"

android:layout_marginLeft="5dip"

android:layout_width="wrap_content"

android:layout_height="wrap_content"/>

<TextView

android:layout_toRightOf="@+id/image"

android:padding="2dip"

android:textColor="@drawable/darkgrey"

android:layout_marginLeft="5dip"

android:id="@+id/sub"

android:layout_below="@+id/company"

android:layout_width="wrap_content"

android:layout_height="wrap_content"/>

</RelativeLayout>

Now need to change the main activity class as follows -

package com.customspinnerdemo;

import android.app.Activity;

import android.content.Context;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.ImageView;

import android.widget.Spinner;

import android.widget.TextView;

public class CustomSpinnerDemoActivity extends Activity {

String[] strings = {"Motorola","Google",

"Microsoft", "Apple", "Yahoo","Samsung"};

String[] subs = {"Mobile world","Google gives you everything",

"Microsoft king of windows", "Apple you will love it", "Yahoo still strugling","Samsung good"};

int arr_images[] = { R.drawable.motorola,

R.drawable.google, R.drawable.microsoft,

R.drawable.apple, R.drawable.yahoo, R.drawable.samsung};

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Spinner mySpinner = (Spinner)findViewById(R.id.spinner);

mySpinner.setAdapter(new MyAdapter(CustomSpinnerDemoActivity.this, R.layout.row, strings));

}

public class MyAdapter extends ArrayAdapter{

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.company);

label.setText(strings[position]);

TextView sub=(TextView)row.findViewById(R.id.sub);

sub.setText(subs[position]);

ImageView icon=(ImageView)row.findViewById(R.id.image);

icon.setImageResource(arr_images[position]);

return row;

}

Run the application and you will see the customer spinner control. You can also attach the selector to change the background color, change the text etc.

How to add/manage menus in android application

2012-03-13T23:12:00.002-04:00

How to add/manage menu in android application

Menues are very important part of any android applications, creation and managing those menu is little tricky in android. I will cover creation and managing menues in two steps - (You will need to create new android project and put 3 different play.png, record.png, soundon.png and stop.png into drawable folder)

Creating menu items
Managing menu items

Creating Menu Items -

Creating the menu item is pretty simple. We need to override the "onCreateOptionsMenu(Menu menu)" method on your Activity class and need to add menues. Below is my activity class for your reference -

package com.menuitem.test;

import android.app.Activity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.Toast;

public class MenuItemTestActivity extends Activity {

private boolean isPlayStarted = false;

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// TODO Auto-generated method stub

menu.add(1, 101, 1, "Play").setIcon(R.drawable.play);

menu.add(1, 102, 2, "Record").setIcon(R.drawable.record);

menu.add(1, 103, 3, "Sound").setIcon(R.drawable.soundon);

return super.onCreateOptionsMenu(menu);

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// TODO Auto-generated method stub

switch(item.getItemId()) {

case 101:

Toast.makeText(getApplicationContext(), "Play clicked", Toast.LENGTH_LONG).show();

isPlayStarted = true;

break;

case 102:

Toast.makeText(getApplicationContext(), "Record clicked", Toast.LENGTH_LONG).show();

break;

case 103:

Toast.makeText(getApplicationContext(), "Sound clicked", Toast.LENGTH_LONG).show();

break;

}

return super.onOptionsItemSelected(item);

}

Managing Menu Items -

Managing menu items are nothing but enabling and disabling some of the menu options, or adding the icons depending on the selected one etc. In this, we will change the menu item's icon and title depending on some conditions. So there is "onPrepareOptionsMenu" method which is called once user click on menu button and before displaying the menues in UI, this method is called. So you can include the code to change the title, icon of the menu item in this method. Apart from that, you can also enable/disable the menu item. Please see all the methods available for MenuItem.

At the time of first call -

After clicking on Play menu, and again press the menu button -

My activity class will look like this -

package com.menuitem.test;

import android.app.Activity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.Toast;

public class MenuItemTestActivity extends Activity {

private boolean isPlayStarted = false;

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// TODO Auto-generated method stub

menu.add(1, 101, 1, "Play").setIcon(R.drawable.play);

menu.add(1, 102, 2, "Record").setIcon(R.drawable.record);

menu.add(1, 103, 3, "Sound").setIcon(R.drawable.soundon);

return super.onCreateOptionsMenu(menu);

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// TODO Auto-generated method stub

switch(item.getItemId()) {

case 101:

Toast.makeText(getApplicationContext(), "Play clicked", Toast.LENGTH_LONG).show();

if (isPlayStarted) {

isPlayStarted = false;

}else {

isPlayStarted = true;

}

break;

case 102:

Toast.makeText(getApplicationContext(), "Record clicked", Toast.LENGTH_LONG).show();

break;

case 103:

Toast.makeText(getApplicationContext(), "Sound clicked", Toast.LENGTH_LONG).show();

break;

}

return super.onOptionsItemSelected(item);

}

@Override

public boolean onPrepareOptionsMenu(Menu menu) {

// TODO Auto-generated method stub

MenuItem item = menu.findItem(101);

if (isPlayStarted) {

item.setTitle("Stop").setIcon(R.drawable.stop);

} else {

item.setTitle("Play").setIcon(R.drawable.play);

}

return super.onPrepareOptionsMenu(menu);

}

Run the application and you will see the same screens as mentioned above.

How to create custom list view in android application

2012-02-08T23:10:00.000-05:00

How to create custom list view in android application

In this tutorial we will learn how to create custom list view, since the standart list view is having only one line which doesn't have facility to format as we want. So the solution here is to create your own custom list view.

Here I am creating a custom list view which will have Two lines to display the information. Also you can add as many controls you want easily to the each item in the list view.

After the run the custom list will be displayed like this -

To create the above custom list, need to follow below steps.

First create new Android Project.
First you need to create a simple pojo class which will be kind of data holder for your list item. In my case I took the example of Employe, below is my pojo class -

package com.test.customlistviewtest;

import java.util.ArrayList;
import java.util.List;

/**
* @author Raghvendra Kamlesh
*
*/
public class Employe {
  private static List employeList = new ArrayList();
  private String name;
  private String department;

  public Employe(String name, String department) {
  this.name = name;
  this.department = department;
  }

public static List getEmployeList() {
  return employeList;
}

public String getName() {
  return name;
}
public void setName(String name) {
this.name = name;
}
public String getDepartment() {
return department;
}
public void setDepartment(String department) {
this.department = department;
  }
}

Create a new layout file which will be representation of the one item in the list. In my case I am using two text controls to create one item in the list. Here is my hybridlist.xml file which you need to create inside the layout folder.

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

< LinearLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:gravity="center_vertical"

android:descendantFocusability="blocksDescendants"

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

< LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="vertical"

android:layout_weight="1">

< TextView

android:id="@+id/text1"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textSize="15sp"

android:textStyle="bold"

android:text="Text view 1" />

< TextView

android:id="@+id/text2"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textSize="11sp"

android:text="Text view 2" />

< /LinearLayout>

Now need to create a EmployeAdapter class which should extends from
BaseAdapter, and need to provide the implementation of its abstract methods. This is the actual adapter class where we will provide our own view to the custom list.

package com.test.customlistviewtest;

import java.util.List;

import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.LinearLayout;

import android.widget.TextView;

/**

* @author Raghvendra Kamlesh

*

*/

public class EmployeAdapter extends BaseAdapter {

private List employeList;

private Context context;

/**

*

*/

public EmployeAdapter(Context context, List employeList) {

this.context = context;

this.employeList = employeList;

}

/* (non-Javadoc)

* @see android.widget.Adapter#getCount()

*/

public int getCount() {

// TODO Auto-generated method stub

return employeList.size();

}

/* (non-Javadoc)

* @see android.widget.Adapter#getItem(int)

*/

public Object getItem(int position) {

// TODO Auto-generated method stub

return employeList.get(position);

}

/* (non-Javadoc)

* @see android.widget.Adapter#getItemId(int)

*/

public long getItemId(int position) {

// TODO Auto-generated method stub

return position;

}

/* (non-Javadoc)

* @see android.widget.Adapter#getView(int, android.view.View, android.view.ViewGroup)

*/

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

      Employe e = employeList.get(position);



      convertView = (LinearLayout)LayoutInflater.from(context).inflate

(R.layout.hybridlist, null);

      TextView text1 = (TextView)convertView.findViewById(R.id.text1);

      text1.setText(e.getName());

      TextView text2 = (TextView) convertView.findViewById(R.id.text2);

      text2.setText(e.getDepartment());



      return convertView;

}

}
Change the main.xml as below -

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

< LinearLayout

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical"

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

< TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textSize="20sp"

android:textStyle="bold"

android:padding="5dp"

android:text="Custom List Example" />

< ListView

android:id="@+id/lstEmploye"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:padding="10dp" />

< /LinearLayout>

Now in main activity class, you will need to assign employe adapter to list view and then new employe adapter class will take care of displaying hybride.xml layout for each and every item in the list. Also you can capture the on select event, and identify which item user has selected.

package com.test.customlistviewtest;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.ListView;

import android.widget.Toast;

public class CustomListViewTestActivity extends Activity {

ListView lstEmployeView;

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

Employe.getEmployeList().add(new Employe("John leun", "Engineering"));

Employe.getEmployeList().add(new Employe("Meddy yu chan", "Marketing"));

Employe.getEmployeList().add(new Employe("David federal desulmati", "Engineering"));

Employe.getEmployeList().add(new Employe("Denny folkerl mo", "Sales"));

Employe.getEmployeList().add(new Employe("Daniel soln cary", "Admin"));

lstEmployeView = (ListView)findViewById(R.id.lstEmploye);

lstEmployeView.setAdapter(new EmployeAdapter(this, Employe.getEmployeList()));

lstEmployeView.setOnItemClickListener(new OnItemClickListener() {

public void onItemClick(AdapterView arg0, View arg1, int arg2, long arg3) {

Employe selectedEmploye = Employe.getEmployeList().get(arg2);

Toast.makeText(getApplicationContext(), "Selected Employe is ==> " + selectedEmploye.getName(), Toast.LENGTH_LONG).show();

}

});

}

Now the example is completed, you can run the example and see the newly created custom list view. There are so many other possibility also can be achieve by writing our own custom layout for list view. We can add images, check boxes, radio buttons and many other controls inside the hybridlayout.xml file to include that for each and every list item.

If you want to do customization of the list item like changing the background color, text color on focus or on select see the "Change the background, text color for custom list view on focus and click" post.

How to create AutoComplete text view in Android Application

2012-02-08T19:58:00.002-05:00

How to create AutoComplete text view in Android Application

In this tutorial, we will learn how to create Auto complete text view. In this example I am using hard corded value, in real world these value can be fetched from DB, RSS feed or from some other sources.

Create new Android project.
Add autotext view layout in main.xml file as shown below -

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

< LinearLayout

android:id="@+id/widget32"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical"

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

< AutoCompleteTextView

android:id="@+id/textAutoComplete"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:padding="15dp"

android:layout_marginLeft="20dp"

android:text=""

android:textSize="18sp" />

< /LinearLayout>

Now need to attach the adapter to this auto complete view in activity class. I am using hard coded string array for demo purpose -

package com.test.autocompletetest;

import android.app.Activity;

import android.os.Bundle;

import android.widget.ArrayAdapter;

import android.widget.AutoCompleteTextView;

public class AutoCompleteTest extends Activity {

private String[] sports = { "Cricket", "Football", "Table tenis", "Hockey", "Others" };

AutoCompleteTextView acTextView;

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

ArrayAdapter adapter =

new ArrayAdapter

(this,android.R.layout.simple_dropdown_item_1line, sports);

acTextView = (AutoCompleteTextView)findViewById(R.id.textAutoComplete);

//Assigning the threshold value for auto complete view, so here once

//user type one character then all the items from the adapter matching

//that character will be displayed.

acTextView.setThreshold(1);

//Assigning the adapter to auto complete view.

acTextView.setAdapter(adapter);

}

Run the application and you will see the auto complete text view will be populated with matching to your first character which you type.

How to create tabs in android application

2012-02-08T19:22:00.000-05:00

How to create Tabs in android application

In this tutorial we will learn how to create tabs in android application and setting the height of the tabs.

Application will looks like this -

Create a new android project.
Create 3 different layout and 3 different activity as given below -

Layouts -

tab1_layout.xml

< ?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:text="Tab 1"

android:padding="15dip"

android:textSize="18dip"

android:layout_width="fill_parent"

android:layout_height="wrap_content" />

< /LinearLayout>

tab2_layout.xml

< ?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:text="Tab 2"

android:padding="15dip"

android:textSize="18dip"

android:layout_width="fill_parent"

android:layout_height="wrap_content"/>

< /LinearLayout>

tab3_layout.xml

< ?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:text="Tab 3"

android:padding="15dip"

android:textSize="18dip"

android:layout_width="fill_parent"

android:layout_height="wrap_content"/>

< /LinearLayout>

Activity Classes -

Tab1.java

package com.test.tabtest;

import android.app.Activity;

import android.os.Bundle;

public class Tab1 extends Activity {

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.tab1_layout);

}

Tab2.java

package com.test.tabtest;

import android.app.Activity;

import android.os.Bundle;

public class Tab2 extends Activity {

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.tab2_layout);

}

Tab3.java

package com.test.tabtest;

import android.app.Activity;

import android.os.Bundle;

public class Tab3 extends Activity {

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.tab3_layout);

}

Now create the main layout and main activity class which will extends from TabActivity as shown below -

Layout main.xml -

< ?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:text="This is tab test!!!"

android:padding="15dip"

android:textSize="18dip"

android:layout_width="fill_parent"

android:layout_height="wrap_content"/>

< TabHost

android:id="@android:id/tabhost"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

< LinearLayout

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

< TabWidget

android:id="@android:id/tabs"

android:layout_width="fill_parent"

android:layout_height="wrap_content" />

< FrameLayout

android:id="@android:id/tabcontent"

android:layout_width="fill_parent"

android:layout_height="fill_parent"/>

< /LinearLayout>

< /TabHost>

< /LinearLayout>

TabTest.java - main activity class -

package com.test.tabtest;

import android.app.TabActivity;

import android.content.Intent;

import android.os.Bundle;

import android.widget.TabHost;

import android.widget.TabHost.TabSpec;

public class TabTest extends TabActivity {

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabSpec tab1spec = tabHost.newTabSpec("Tab1");

tab1spec.setIndicator("Tab1");

Intent tab1Intent = new Intent(this, Tab1.class);

tab1spec.setContent(tab1Intent);

TabSpec tab2spec = tabHost.newTabSpec("Tab2");

tab2spec.setIndicator("Tab2");

Intent tab2Intent = new Intent(this, Tab2.class);

tab2spec.setContent(tab2Intent);

TabSpec tab3spec = tabHost.newTabSpec("Tab3");

tab3spec.setIndicator("Tab3");

Intent tab3Intent = new Intent(this, Tab3.class);

tab3spec.setContent(tab3Intent);

// Adding all TabSpec to TabHost

tabHost.addTab(tab1spec);

tabHost.addTab(tab2spec);

tabHost.addTab(tab3spec);

//Adjusting the tab height as per need.

tabHost.getTabWidget().getChildAt(0).getLayoutParams().height=40;

tabHost.getTabWidget().getChildAt(1).getLayoutParams().height=40;

tabHost.getTabWidget().getChildAt(2).getLayoutParams().height=40;

}

Add entries in AndroidManifest.xml file for 3 new tab activities as shown below -

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

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

package="com.test.tabtest"

android:versionCode="1"

android:versionName="1.0">

< application android:icon="@drawable/icon" android:label="@string/app_name">

< activity android:name=".TabTest"

android:label="@string/app_name">

< intent-filter>

< action android:name="android.intent.action.MAIN" />

< category android:name="android.intent.category.LAUNCHER" />

< /intent-filter>

< /activity>

< activity android:name=".Tab1" />

< activity android:name=".Tab2" />

< activity android:name=".Tab3" />

< /application>

< /manifest>

Run the application and you will see the application having 3 different tabs and you can also put images for each tab by using below syntax -

Instead of

tab1spec.setIndicator("Tab1");

Use

tab1spec.setIndicator("Tab1", getResources().getDrawable(R.drawable.icon));

How to zoom and drag images in Android app

2012-02-08T18:22:00.001-05:00

How to zoom and drag images in Android app

This tutorial will teach you, how to create android application with image zoom and scroll facility.

First create the android project and follow the below steps. I used Android 1.6 for creating this example.

Add one image file in drawable folder with named "tempimage".
Create the main.xml with following configuration -

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

<FrameLayout

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

android:id="@+id/root"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<ImageView android:id="@+id/imageview"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:src="@drawable/tempimage"

android:scaleType="matrix"

android:adjustViewBounds="true"

android:layout_gravity="center">

ImageView>

FrameLayout>

Create the onlick listener as given below -

package com.test.image.zoomtest;

import android.graphics.Matrix;

import android.graphics.PointF;

import android.util.FloatMath;

import android.view.MotionEvent;

import android.view.View;

import android.view.View.OnTouchListener;

import android.widget.ImageView;

public class Touch implements OnTouchListener {

// These matrices will be used to move and zoom image

Matrix matrix = new Matrix();

Matrix savedMatrix = new Matrix();

// We can be in one of these 3 states

static final int NONE = 0;

static final int DRAG = 1;

static final int ZOOM = 2;

int mode = NONE;

// Remember some things for zooming

PointF start = new PointF();

PointF mid = new PointF();

float oldDist = 1f;

@Override

public boolean onTouch(View v, MotionEvent event) {

ImageView view = (ImageView) v;

// Dump touch event to log

dumpEvent(event);

// Handle touch events here...

switch (event.getAction() & MotionEvent.ACTION_MASK) {

case MotionEvent.ACTION_DOWN:

savedMatrix.set(matrix);

start.set(event.getX(), event.getY());

mode = DRAG;

break;

case MotionEvent.ACTION_POINTER_DOWN:

oldDist = spacing(event);

if (oldDist > 10f) {

savedMatrix.set(matrix);

midPoint(mid, event);

mode = ZOOM;

}

break;

case MotionEvent.ACTION_UP:

case MotionEvent.ACTION_POINTER_UP:

mode = NONE;

break;

case MotionEvent.ACTION_MOVE:

if (mode == DRAG) {

// ...

matrix.set(savedMatrix);

matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);

} else if (mode == ZOOM) {

float newDist = spacing(event);

if (newDist > 10f) {

matrix.set(savedMatrix);

float scale = newDist / oldDist;

matrix.postScale(scale, scale, mid.x, mid.y);

}

break;

}

view.setImageMatrix(matrix);

return true; // indicate event was handled

}

/** Show an event in the LogCat view, for debugging */

private void dumpEvent(MotionEvent event) {

String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",

"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };

StringBuilder sb = new StringBuilder();

int action = event.getAction();

int actionCode = action & MotionEvent.ACTION_MASK;

sb.append("event ACTION_").append(names[actionCode]);

if (actionCode == MotionEvent.ACTION_POINTER_DOWN

|| actionCode == MotionEvent.ACTION_POINTER_UP) {

sb.append("(pid ").append(

action >> MotionEvent.ACTION_POINTER_ID_SHIFT);

sb.append(")");

}

sb.append("[");

for (int i = 0; i < event.getPointerCount(); i++) {

sb.append("#").append(i);

sb.append("(pid ").append(event.getPointerId(i));

sb.append(")=").append((int) event.getX(i));

sb.append(",").append((int) event.getY(i));

if (i + 1 < event.getPointerCount())

sb.append(";");

}

sb.append("]");

}

/** Determine the space between the first two fingers */

private float spacing(MotionEvent event) {

float x = event.getX(0) - event.getX(1);

float y = event.getY(0) - event.getY(1);

return FloatMath.sqrt(x * x + y * y);

}

/** Calculate the mid point of the first two fingers */

private void midPoint(PointF point, MotionEvent event) {

float x = event.getX(0) + event.getX(1);

float y = event.getY(0) + event.getY(1);

point.set(x / 2, y / 2);

}

Set the image view ontouch listener as given below -

package com.test.image.zoomtest;

import android.app.Activity;

import android.os.Bundle;

import android.widget.ImageView;

public class ImageZoomTestActivity extends Activity {

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

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

iv.setOnTouchListener(new Touch());

}

Now you are ready to run the application.

How to implement Voice Recognition in android application

2012-01-18T21:06:00.000-05:00

How to implement Voice Recognition in android application

Here is the tutorial to create android application which will convert voice to text, and then that text you can use where ever you want.

First create the Android project and follow the below steps [I had give VoiceToText as project name]-

1. No changes are required in AndroidManifest.xml file. Just for your reference below is my AndroidManifest.xml file

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

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

package="com.voicetotext"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk android:minSdkVersion="8" />

<application

android:icon="@drawable/ic_launcher"

android:label="@string/app_name" >

<activity

android:label="@string/app_name"

android:name=".VoiceToTextActivity" >

<intent-filter >

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

</application>

</manifest>

2. Create UI which will have Button and list view, following is my main.xml file. [If you want you can create new file otherwise use the default main.xml file]

<?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:paddingBottom="4dip"

android:text="Click button and start speaking" />

<Button android:id="@+id/speakBtn"

android:layout_width="fill_parent"

android:onClick="speakButtonClicked"

android:layout_height="wrap_content"

android:text="Hit Me!" />

<ListView android:id="@+id/resultList"

android:layout_width="fill_parent"

android:layout_height="0dip"

android:layout_weight="1" />

</LinearLayout>

3. Now need to code your main activity class, once user hit the Hit Me! button it will listen and translate voice to text and display that into resultList list view. Following is my main activity class -

package com.voicetotext;

import android.app.Activity;

import android.os.Bundle;

import android.content.Intent;

import android.content.pm.PackageManager;

import android.content.pm.ResolveInfo;

import android.speech.RecognizerIntent;

import android.view.View;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.ListView;

import java.util.ArrayList;

import java.util.List;

public class VoiceToTextActivity extends Activity {

private static final int REQUEST_CODE = 1234;

private ListView resultList;

/**

* Called when the activity is first created.

@Override

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

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

resultList = (ListView) findViewById(R.id.resultList);

// Disable button if no recognition service is present

PackageManager pm = getPackageManager();

List RecognizerActivities = pm.queryIntentActivities(

new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);

if (RecognizerActivities.size() == 0)

{

speakBtn.setEnabled(false);

speakBtn.setText("Recognizer unavailable!!!");

}

/**

* Handle the action of the button being clicked

public void speakButtonClicked(View v)

{

startVoiceRecognitionActivity();

}

/**

* Fire an intent to start the voice recognition activity.

private void startVoiceRecognitionActivity()

{

Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);

intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,

RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);

intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Voice To Text Demo…");

startActivityForResult(intent, REQUEST_CODE);

}

/**

* Handle the results from the voice recognition activity.

@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data)

{

if (requestCode == REQUEST_CODE && resultCode == RESULT_OK)

{

// Populate the resultList with the String values the recognition engine thought it heard

ArrayList matches = data.getStringArrayListExtra(

RecognizerIntent.EXTRA_RESULTS);

resultList.setAdapter(new ArrayAdapter(this, android.R.layout.simple_list_item_1,

matches));

}

super.onActivityResult(requestCode, resultCode, data);

}

Now you can run this application and speak the word or sentences, it will start converting those words into text and later you can use those text as a command to perform any tasks.

Note: This will not work on emulator, you will need actual device to test this application.

Avoid Cross Site Scripting popup in IE

2011-11-21T19:47:00.001-05:00

Avoid Cross Site Scripting popup in IE

Microsoft IE has a security feature called, Cross Site Scripting (XSS) Filter, in which IE doesn't allow cross site script to run and help to prevent cross site attack. To avoid this popup there is a setting in IE which is enable by default. To disable this popup, follow the below steps -

Goto Tools-->Internet Option.
Click on the Security Tab
Click on Custom Level Button
Scroll down till the end and look for "Enable XSS Filter" setting.
Select "Disabled" and click on OK
Restart your browser and you will not see any cross site script popup.

The above approach will not work if you have huge number of clients and asking all of them to follow the above steps will be tedious for them. There is a way to handle this from application front.

IE browser read the "X-XSS-Protection" header, and if the value of this header is set to 0, IE doesn't show the cross site script popup.

To set this in java, you can set the header in response object as given below -

response.setHeader("X-XSS-protection", 0);

You can set the same header in any language before sending response to client and browser will respect this header.

2011-11-21T19:06:00.001-05:00

How to Make configuration changes in apk file

Decompile apk, make changes, compile and create apk.

Android puts all the resources in binary format under the apk file, and cannot be read by unpacking the apk file. It needs tool to unzip/decompile so that we can read it and if required, we can make some configuration changes and again create the apk with those changes.

In my example, I am updating the VersionName in AndroidManifest.xml file.

Need to follow the below steps -

Setup the apkTool -

Download apktool-install-windows-* and apktool* file from http://code.google.com/p/android-apktool/ link.
Unpack both these downloaded files into some directory into your local machine (we will refer this location as root directory in our below examples).
If you want to use this frequently, set this path into your environment variable, this is not mandatory step.

Open command prompt and go to your root path.
To decompile your apk, use below command -

apktool d ApkToolTest.apk

Note: Here I have ApkToolTest.apk file which I have created to demo this and copied that apk file into root directory.
Once you run the above command you will see the output like this -

I: Baksmaling...
I: Loading resource table...
I: Loaded.
I: Loading resource table from file: C:\Users\raghvendra\apktool\framework\1.apk
I: Loaded.
I: Decoding file-resources...
I: Decoding values*/* XMLs...
I: Done.
I: Copying assets and libs...

Once this is done, you will see ApkToolTest folder in root directory, with all the resources.

Make the changes into any of the configuration file, In my case, I made the changes in AndroidManifest.xml file and updated the VersionName field.
Once you done with all your changes, run the below command to again compile the project and create the apk file again -

apktool b ApkToolTest

The above command will output like below -

I: Checking whether sources has changed...
I: Smaling...
I: Checking whether resources has changed...
I: Building resources...
I: Building apk file...

Once that's done you will find the ApkToolTest.apk file having updated resources information You can find the updated apk under dist folder, In my case it is \ApkToolTest\dist\ApkToolTest.apk. You can deploy this updated apk file to any devices, or Market, or any app store.
Once you try to install this app onto emulator or any device before releasing to any of the public use, and if you see "INSTALL_PARSE_FAILED_NO_CERTIFICATES" error, then you have to sign your apk. To sign apk follow the below steps -

Make sure you have all the required setup ready to sign your apk Refer this link - "http://developer.android.com/guide/publishing/app-signing.html"
Generate your private key and run the jarsigner to sign your apk file.

How to setup Android Development Environment on Mac

2011-11-15T20:56:00.000-05:00

Setting up the develop environment for Android is little tricky in MAC OS. To setup development environment in Mac OS for android, follow the below steps -

Android SDK installation:

First need to download the Android SDK from http://developer.android.com/sdk/index.html. [Note: download the MAC OS sdk from the list.]
Unzip the downloaded sdk and copy this in some location into your local drive. I am copying into /Applications, so my path will become "/Applications/android-sdk-macosx/".
Add the JAVA_HOME, ANDROID_SDK, PATH, and NO_NEON into .bashrc file. To add these entry into your .bashrc file follow the below steps:

First check if the file is exists, open Terminal.app (in Applications/Utilities) and type "ls -a ~/" This will list all of the file in your home directory. If .bashrc exists, then you can edit the file by typing "open -a /Applications/TextEdit.app .bashrc".
If the file doesn't exist, then open TextEdit, select Format=>Make Plain Text, then paste in the necessary commands. Once that's done, go to File=>Save As, uncheck "If no extension is provided, use ".txt", type in the name ".bashrc", and save the file. TextEdit will warn you that files beginning with a "." are reserved for the system. Click the "Use '.'" button. Note: Remember to save this on your home location.
Add Following entries into your .bashrc file -

export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Home
export ANDROID_SDK=/Applications/android-sdk-macosx/
export PATH=$PATH:$ANDROID_SDK/tools:$ANDROID_SDK/platform-tools
export NO_NEON=1

Details about above configuration -

Some Mac OS comes with the 64bit version of Java 1.6 installed by default. so we are setting the JAVA_HOME to point at it.
The PATH is not required alias but will make it easy for you to run the Android SDK Manager by typing “android” or the Android Debug Bridge by typing “adb” in the Terminal.
Set NO_NEON to prevent Android compilation from using the Neon CPU enhancements which are not supported on all Android devices (including the Emulator).

Run Android SDK manager to install support for one or more Android OS platform versions. [Not mandatory to install all versions, but at least one version will require to proceed with the further steps.] To install run the $ANDROID_SDK/tools/android command and select at least one sdk and API version. It might take some time depending upon your selection.

Android NDK installation:

The Android NDK is a toolset that lets you embed components that make use of native code in your Android applications.

Download Android NDK from http://developer.android.com/sdk/ndk/index.html. [Note: Download the MAC OS version from the list]
Unzip the downloaded ndk and copy this into some location into your local drive. I am copying into /Applications, so my path will be "/Applications/android-ndk-r7".
Add below entries into your .bashrc file -

export ANDROID_NDK=/Applications/android-ndk-r7

export PATH=$PATH:$ANDROID_NDK:$ANDROID_NDK/tool

Android Eclipse Plugin installation (ADT):

Start Eclipse.
Click on Help-->Install New Software.
Put https://dl-ssl.google.com/android/eclipse/” into the “Work with:” field.
Press Enter, check the below table will populate automatically with the options.
Check the Developer Tool check box to select all.
Click Next, Next and select the Accept agreement And Finish.
Once it will finish the installation, It will ask you for the restart, so click on Restart Now to restart eclipse.

Android Eclipse Plugin Configuration (ADT):

Once Eclipse restarted, We need to configure the installed ADT plugin.

Goto Eclipse-->Preferences menu.
Select Android from the left side list.
Put your $ANDROID_SDK location into SDK Location field. In my case it's "/Applications/android-sdk-macosx"
Click on Apply button and you will see all the android platform versions which you had installed before.
Hit OK, and now your Android development environment is all setup correctly.

********** Create Hello world app to start with ***************

How to setup Android Development Environment on Windows

2011-11-14T22:04:00.001-05:00

To setup development environment in windows machine for android, follow the below steps -

Install Java version 1.5 or above .
Download Android-sdk_rXX-windows.zip from http://developer.android.com/sdk/index.html
Extract Android-sdk_rXX-windows.zip into C:\Android or your favorite folder on your local drive.
Append “C:\Android\android-sdk-windows\tools” to PATH environment variable value as shown below.

Install Eclipse - Europa, GyneMede, Galileo etc. [Note: From here on, we will be presenting the slide sequence as in Eclipse Galileo.]
Start Eclipse.
Go to Help ->Install New Software- >Click on Add Button ->”Add Site” box will open.
In Name text box type “Android Plugin” and in Location (URL) text box type “https://dl-ssl.google.com/android/eclipse/” .Click OK and then Finish.

In Install box, you will see list of “All Available software” “Work with” drop down. Select “Android PlugIn - https://dl-ssl.google.com/android/eclipse/”.

In “Name” box , you will see check box “Developer Tools” (On clicking +, Android DDMS and Android Toc along with version should be visible). Select all and click finish.

Installation will take some time. To check if Android is installed correctly go to Window->Preferences ->Install/Update->Available Software sites. “Android PlugIn - https://dl-ssl.google.com/android/eclipse/” Should be visible under “Name” and “Location” section. You can also check from command prompt using the command – “Android”.

Select Window ->“Android SDK and ADV Manager”, A dialogue box will open with three Options on left hand side:

Virtual Devices
Installed Packages
Available Packages

Select “Available Packages”, Expand “+” icon, choose “SDK Platform 2.1, API 7, revision 1”. [Note: Please do not select all SDK versions available since it will take too much time to download.]
Select “Virtual Devices” and click on “New” button on right hand side.
“Create new AVD Manager” box will open. In “Name” text box, enter appropriate name for e.g. “AVD”. In Target drop down select “Android 2.1 – API Level 7”and click on “Create AVD” Button.

And it’s all done. You are ready to create “Android Application” as a normal Java Program.

****** Send me email if you have any queries regarding this post *********