勇於改變

Implement an AppWidget for BozaAlarm - Part I: Limitation

2012-02-04T20:29:00.004+08:00

Today, I released BozaAlarm v4.10 to the Android Market. What's new in this version is the simple AppWidget to display the next enabled alarm.

Here, I'd like to talk about how I implemented this simple widget. Before I go too far, you probably need to take a look at least these two topics,

Just as I said before, there are some limitations in App Widget design and understand these should save you some time.

Basically, the Launcher process hosts AppWidgetHostView for each App Widget and talk with your process through RPC calls. You can image there are many RPC (binder) calls between Launcher and your process. That's why you will use RemoteViews to package your update actions in your process and apply them on the App Widget on the Launcher side. In fact, the RemoteViews is implemented as Command pattern in software terminology.

Now, you can imagine why AppWidget design is so restricted.

Moreover, because it's always unsafe to load classes from other process in a process, you're not allowed to use custom classes in your widget layout. Only built-in widget classes can be used in your layout xml file and only methods tagged by RemotableMethod in these classes are allowed.

Experiment the Tips for reducing APK file size

2012-02-04T14:09:00.000+08:00

I came across this article: Tips for reducing APK file size at SonyEricsson Developer blog. Among them, the one I am aware of is the PNG file optimization. So, I took some time to experiment it.

First, I downloaded the GUI wrapper of command-line optimizer ImageOptim and optimize the PNG files at res/ directory. According to the result, it reduce total file size from 748K bytes to 700K bytes.

Second, I recompile the release binary of my application. But, the size of APK file remains the same as the one w/o PNG optimization.

Hmm. I repeated this process some times to make sure I didn't miss some important steps. While I was wondering, I noticed some messages spewed out during compilation like,

[crunch] Processing image to cache: /Users/yenliangl/Work/Android/bozaalarm-android/res/drawable-hdpi/handler_app.png => /Users/yenliangl/Work/Android/bozaalarm-android/bin/res/drawable-hdpi/handler_app.png

Looks like PNG optimization has been included in the standard Android tool v14??

This should confirm my guess. From official site of Android tool, it says that in revision 14, aapt optimizes PNG during compilation.

png processing in aapt.
When aapt packages the resources, its main goal is to compile the XML to binary format and to create a resource table with all the resource values (string, color, ids, etc...). Additionally, it processes the png files to optimize them (for instance, pre-processing of 9-patches).
Because the aapt process is not incremental, this means every build goes through all png files and processes them always. For large projects with numerous (and/or large) png this process could take a long time.
Revision 14 now processes the png files outside of the aapt packaging step and caches them. Only modified png files are re-processed.

TimePicker/DatePicker with keyboard input problem

2012-01-06T21:01:00.000+08:00

I got some complaints from users saying they can't use keyboard to input in TimePicker or DatePicker widgets and found that this bug has been posted on Android developer forum for some time.

The quick workaround for this bug is,

Publish org to remote host through ssh

2012-01-05T16:34:00.001+08:00

I've used Emacs org-mode to manage my personal notes and work stuff for a while. Its flexibility always amazes me.

Normally, I keep my personal notes in a Dropbox directory that are synced automatically. But, for work stuff, I created a local directory for them in intranet and published them to a secured remote host through ssh. The org-publish supports this feature well after you've configured ssh.

Customize Emacs compile

2012-01-05T16:04:00.002+08:00

At work, I use M-x compile to build the project I'm working on. Chances are that default compile-command is not what you want. You can customize it and bind it to hotkeys as follows,

Now, you can use F8, F9 to build the optimized and debug version.

Create Emacs server for each GNU Screen automatically

2011-12-27T15:21:00.007+08:00

I am a heavy user of GNU screen and Emacs at work and home. In the past, I created different GNU Screen instances for different projects and only one instance of Emacs server in one machine. For instance, you are aked to fix bugs in threee code branches and some fixes can't go into certain branches, I need to be very careful when I edit and switch buffers because only once emacs server out there.

What I really need to have setup like this,

Now, whenever you edit or switch files in a GNU screen by emacsclient, you can sit back and relax for a while. But, the problem is how do I make this a bit automatic? If you need to execute 'emacs --daemon=serverN' for every created GNU Screen, that will be very troublesome.
Here is what I have done to make this happen,

Now, when you instantiate GNU Screen by 'ws_XXX' aliases, an Emacs server identified by 'XXX' is created for you. And then you can use 'et' to edit a file in the proper Emacs server.

The only thing I don't like is that I am compelled to use another alias 'kill-emacs' to kill Emacs server. I often 'pkill' to kill process, but this will kill all Emacs servers in the same machine which is absolutely not the behavior I want.

The last thing to do is to patch the source code of emacsclient. In my experiment, emacsclient in the latest stable release (23.3b) doesn't pass correct argument for Emacs to start its daemon mode. So, I made minor changes to make it right.

After recompile and install, you can start using these two power tools in this way as I do.

Load machine-dependent bash setting

2011-05-27T18:43:00.000+08:00

I own several computers and each is running different OS on it. We all know that maintaining different settings for different OS is very cumbersome. A simple solution for this is to separate common settings and machine-dependent settings into different files like this,

MNAME=`uname -s`
MBASHRC=$HOME/Settings/bashrc.${MNAME,,}
if [ -f $MBASHRC ]; then
    echo "==> loading $MBASHRC"
    . $MBASHRC
fi

In this way, all you need to do is to write your machine-dependent settings in the bashrc.darwin or bashrc.linux.

MacOSX-like open command in Ubuntu and Windows/Cygwin.

2011-05-27T18:25:00.002+08:00

I always find 'open' command in MacOSX is very useful for people always hanging around in the Terminal. To get the similar behavior in Ubuntu or other Linux system, we can create an alias such as,

My new Android application TallyCounter

2011-05-16T21:24:00.001+08:00

I've published a new application, TallyCounter, on the Android Market.

It's very easy to use. You can download it on this link.

Run Android CTS

2011-05-04T11:30:00.000+08:00

Recently, I was asked to look into CTS report of my work. So, I downloaded CTS on Android website and started running it. After hours of experiments, these are my experiences that should save you some time.

Use SDK 1.6r1 against your CTS. Don't use SDK r10.
Modify maxTestCount to -1 in your $CTS_ROOT/repository/host_config.xml
Don't run large test plan. Predefined test plans in the CTS are,

CTS plan

VM plan
Java plan
Android plan

RefApp plan
AppSecurity plan

Signature plan

Performance plan

If you run into errors complaining this "Installing met .... due to unknown reasons", try to run a customized smaller test plan composed of nonExecuted packages.

add --plan reset_of_packages. It prompts you available packages to add into this plan and you can add packages that haven't run yet since the error happens.

You can run CTS in Linux, Windows or Ubuntu. The whole CTS suite is just a script wrapped on top of "java -cp". It should be platform-independent. If you are running CTS on Windows/cygwin system,

Move the definition of ${JARS} in your startcts to the following,

JARS=`cygpath -w -p ${CTS_LIB}:${DDM_LIB}:${JUNIT_LIB}:${HOSTTEST_LIB}`

and, this line

java ${JAVA_OPTS} -cp ${JARS} com.android.cts.TestHost `cygpath -w ${CONFIG}` "$@" ${DDCONFIG}

New alpha version for features I've implemented since v3.07b

2011-04-27T22:22:00.000+08:00

I've compiled a new alpha version that includes features I've implemented since the release of v3.07b on the Android Market. These features include,

New alarm action for launching application.
New equation mode on the AlarmAlert activity to unlock snooze/dismiss buttons.
The redesigned password input widget.

Screenshots are uploaded to my Picasa space.

Select an application to launch

Set password for an alert

Solve a simple equation to unlock snooze/dismiss buttons

Enter specified or random-generated password to unlock snooze/dismiss buttons

You can install this new alpha version from my Dropbox space.

New alarm action to launch an application main activity

2011-04-26T22:09:00.000+08:00

I was struggling to add this feature my application because I believe it won't do much help. Still, I tried to implement this as a practice. It's pretty easy to get all installed applications on the phone by these lines.

and you can launch the main activity of an application by

Intent launchIntent = pm.getLaunchIntentForPackage(packageName);
launchIntent.setFlags(Intent.FLAG_ACTIVIY_NEW_TASK|Intent.FLAG_ACTIVITY_NO_USER_ACTION);
context.startActivity(launchIntent);

What I said it doesn't do much help is that you can only bring up an activity unless you know how to talk to it through its public interface.

How to toggle power controls (Wi-Fi, GPS, bluetooth, brightness, sync)

2011-04-22T17:42:00.000+08:00

This topic has been asked on Android forums regularly and sometimes you are told not to turn on/off GPS/Bluetooth without consents from users. That's true.

Despite this consent issue, what is the simplest way to toggle power controls programmatically? For Android 2.1+, my opinion is to take advantage of the code Settings already provides.

Intent intent = new Intent();
intent.setClassName("com.android.settings","com.android.settings.widget.SettingsAppWidgetProvider");
intent.addCategory(Intent.CATEGORY_ALTERNATIVE);
intent.setData(Uri.parse("custom:" + getButtonId()));
context.sendBroadcast(intent);

The getButtonId() returns the button id on the PowerControl widget. You can try to put this widget on your device. It is not impossible that these button ids are changed in the future Android release or by vendors. But, I have to say it's not very likely to happen.

Wi-Fi: 0
Brightness: 1
Sync: 2
GPS: 3
Bluetooth: 4

Another advantage of using this is the reduction of hardware permissions you have to declare.

New alpha version of BozaAlarm v3.01a

2011-04-21T16:12:00.000+08:00

I've implemented these experimental changes into this new alpha version - v3.01a.

GPS and Bluetooth toggling action.
Wi-Fi action has no toggling option any more. It toggles current Wi-Fi state.
Honor user's group-by setting when viewing alarms through View/All.

This new test release can be downloaded here in my Dropbox space.

How CursorAdapter works

2011-04-09T15:07:00.002+08:00

For people who are new to Android development, sometimes, they are wondering why CursorAdapter know when to refresh your UI and how the connection between your model and view is set?

I looked into the Android source code and learned that two key method calls will establish this connection. This following diagram was drawn in order to understand how your model (Database) and View (AdapterView) are bound together. From this diagram, we can see

Cursor.setNotificationUri(ContentResolver, Uri)
ContentResolver.notifyChange(...)

The first call will insert an hash entry (Uri, Cursor) into the hash map hold by ContentResolver (ContentService) so that whenever the data pointed by this Uri object is changed, it will requery the Cursor object.

But the question is how ContentResolver knows your data is changed? It's your responsibility to tell it. In your implementation of ContentProvider or internal database, when you insert, delete, update the data successfully, you need to call ContentResolver.notifyChange(Uri, ...) to let ContentResolver know it should requery the hosted Cursor object keyed by the passed Uri.

As for the internal database, if it is SQLiteDatabase, I prefer using non-exported ContentProvider because its well-established interface.

Customize the layout of PreferenceActivity

2011-04-09T11:37:00.000+08:00

In my application, I'd like to have non-Preference items shown on a PreferenceActivity like the TimePicker widget below,

Actually, it is easy to get this. The PreferenceActivity sets its content view to a ListView with list as its view id.

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(com.android.internal.R.layout.preference_list_content);
        
        mPreferenceManager = onCreatePreferenceManager();
        getListView().setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
    }

and this preference_list_content is just a ListView,

which can be replaced by your own layout xml file as long as it contains one ListView with android:id/list as its id. You can put as many widgets as you want in this layout xml file and use setContentView() to use it in your onCreate() method.

Why TaskKiller prevents my Alarm apps from working

2011-04-08T14:54:00.000+08:00

It is well-known that task killers on the Android Market prevents Alarm applications from working. But why? To understand this, we should understand how alarms in Android are handled. A hardware alarm event should go through 2 layers to bring up your software component.

Hardware alarm event
AlarmManagerService
Your application components to handle alarms

The AlarmManagerService stores the information required to link hardware alarm event to your application components. The task killer actutually removes these information from AlarmManagerService and this is why your Alarm application doesn't work after a task killer kills your application.

For devices running Android 2.1 and below, the method the task killer uses to kill an application is ActivityManager.restartPackage(String) that in turn triggers the UninstallReceiver defined in AlarmManagerService to remove all links registered by your application.

class UninstallReceiver extends BroadcastReceiver {
        public UninstallReceiver() {
            IntentFilter filter = new IntentFilter();
            filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
            filter.addAction(Intent.ACTION_PACKAGE_RESTARTED); // <------ this line
            filter.addDataScheme("package");
            mContext.registerReceiver(this, filter);
        }
        
        @Override
        public void onReceive(Context context, Intent intent) {
            synchronized (mLock) {
                Uri data = intent.getData();
                if (data != null) {
                    String pkg = data.getSchemeSpecificPart();
                    removeLocked(pkg);
                    mBroadcastStats.remove(pkg);
                }
            }
        }
    }

But, in Android 2.2, things changed. The restartPackage method is changed to be just a wrapper of a new method killBackgroundProcesses. So, task killers on the Market are doing the same thing as default Out-Of-Memory (OOM) killer. Although we can still install them to proactively kill processes, but they are not necessary any more.

A Preference that get result back from Activity it started

2011-04-08T14:25:00.001+08:00

We know that Preferences in Android don't provide public interface to get result back from the activities they launched. The only clue we can find is that RingtonePreference has done the exact thing in protected level. Fortunately, It is very easy to extend RingtonePreference.

So, this is the behavior of RingtonePreference that we want to achieve,

Click to start our activity (not RingtonePicker)
Get result back from activity and store it as SharedPreference for later use. (any kind of result other than Ringtone Uri)

you definitely need to do some modifications on RingtonePreference as I did.

I am developing a ContactPreference in my application that starts an activity for user to pick contacts and returns them back to the ContactPreference. Here is what I did by overriding RingtonePreference,

public class ContactPreference extends android.preference.RingtonePreference {
    // 
    @Override
    public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
        if (super.onActivityResult(requestCode, resultCode, data)) {
            ArrayList addrList =null;
            if (data != null) {    
                addrList = data.getStringArrayListExtra(ContactPicker.EXTRA_ADDRESS_LIST);
            }
            onSaveAddressList(addrList);                       
            return true;                     
        }                          
        return false;             
    }

    @Override
    protected void onPrepareRingtonePickerIntent(Intent intent) {
        // Remove all extras already placed by RingtonePreference
        intent.setAction(null);
        intent.removeExtra(RingtoneManager.EXTRA_RINGTONE_EXISTING_URI);
        intent.removeExtra(RingtoneManager.EXTRA_RINGTONE_SHOW_DEFAULT);
        intent.removeExtra(RingtoneManager.EXTRA_RINGTONE_DEFAULT_URI);
        intent.removeExtra(RingtoneManager.EXTRA_RINGTONE_SHOW_SILENT);
        intent.removeExtra(RingtoneManager.EXTRA_RINGTONE_TYPE);

        // Set the activity we want to start.
        intent.setClass(getContext(), ContactPicker.class);

        // Addresses that was picked. So that your activity can handle it, s.t., checked them on/off.
        ArrayList addrList = onRestoreAddressList();
        if (addrList != null) {
            intent.putStringArrayListExtra(ContactPicker.EXTRA_ADDRESS_LIST, addrList);
        }
    }

aidl file of Winamp

2011-03-25T16:45:00.002+08:00

I've been experimenting adding support for Winamp in my application that is supposed to be released soon. But the first thing I need to consider is a correct Android interface file that describes the interface Winamp's music service has. After several trial&error, I have some findings,

Winamp uses built-in MediaStore provider.

Playlists created in built-in Music application can be seen in Winamp and playlists created from Winamp can be seen in built-in Music application.

Winamp uses built-in IMediaPlaybackService.aidl which package names replaced with com.nullsoft.winamp. Still, it changes some code that makes my integration difficult. Here are my steps to guess its aidl interface,

Installed Winamp in a rooted device and debug it.
Because Winamp doesn't obfuscate its code, we can use Java's reflection to see its class and method interfaces easily. In jdb,

Run 'classes' to see all classes started with com.nullsoft.winamp. You can see one line for com.nullsoft.winamp.IMediaPlaybackService
Run 'methods com.nullsoft.winamp.IMediaPlaybackService' to list all method declaration of this class. You can see it not having differences than standard IMediaPlaybackService.

com.nullsoft.winamp.IMediaPlaybackService duration()
com.nullsoft.winamp.IMediaPlaybackService enqueue(long[], int)
com.nullsoft.winamp.IMediaPlaybackService getAlbumId()
com.nullsoft.winamp.IMediaPlaybackService getAlbumName()
com.nullsoft.winamp.IMediaPlaybackService getArtistId()
com.nullsoft.winamp.IMediaPlaybackService getArtistName()
com.nullsoft.winamp.IMediaPlaybackService getAudioId()
com.nullsoft.winamp.IMediaPlaybackService getMediaMountedCount()
com.nullsoft.winamp.IMediaPlaybackService getPath()
com.nullsoft.winamp.IMediaPlaybackService getQueue()
com.nullsoft.winamp.IMediaPlaybackService getQueueLen()
com.nullsoft.winamp.IMediaPlaybackService getQueuePosition()
com.nullsoft.winamp.IMediaPlaybackService getRepeatMode()
com.nullsoft.winamp.IMediaPlaybackService getShuffleMode()
com.nullsoft.winamp.IMediaPlaybackService getTrackName()
com.nullsoft.winamp.IMediaPlaybackService isPlaying()
com.nullsoft.winamp.IMediaPlaybackService moveQueueItem(int, int)
com.nullsoft.winamp.IMediaPlaybackService next()
com.nullsoft.winamp.IMediaPlaybackService open(long[], int)
com.nullsoft.winamp.IMediaPlaybackService openFile(java.lang.String, boolean)
com.nullsoft.winamp.IMediaPlaybackService openFileAsync(java.lang.String)
com.nullsoft.winamp.IMediaPlaybackService pause()
com.nullsoft.winamp.IMediaPlaybackService play()
com.nullsoft.winamp.IMediaPlaybackService position()
com.nullsoft.winamp.IMediaPlaybackService prev()
com.nullsoft.winamp.IMediaPlaybackService quit()
com.nullsoft.winamp.IMediaPlaybackService removeTrack(long)
com.nullsoft.winamp.IMediaPlaybackService removeTracks(int, int)
com.nullsoft.winamp.IMediaPlaybackService seek(long)
com.nullsoft.winamp.IMediaPlaybackService setQueuePosition(int)
com.nullsoft.winamp.IMediaPlaybackService setRepeatMode(int)
com.nullsoft.winamp.IMediaPlaybackService setShuffleMode(int)
com.nullsoft.winamp.IMediaPlaybackService stop()

Duplicate IMediaPlaybackService.aidl from built-in Music code and replace its package name, include this file in your project.

Although the code builds successfully, it doesn't work as expected.

public void onServiceConnected(ComponentName name, IBinder binder) {
    com.nullsoft.winamp.IMediaPlaybackService s = com.nullsoft.winamp.IMediaPlaybackService.Stub.asInterface(binder);
    try {
        // s.isPlaying() and s.top() are working.
        if (s.isPlaying()) {
            s.stop();
        }

        // s.open() broadcasts com.nullsoft.winamp.queuechanged if audio ids
        // are set successfully. 
        s.open(mData, 0);

        /* s.next() works but only plays one song and causes 
           com.nullsoft.winamp.playstatechanged and com.nullsoft.winamp.metachanged
           broadcasted. */ 
        s.next();

        /* s.play() doesn't work. Guess that MediaPlayer is not initialized if Winamp doesn't 
           change too much from standard Music */
        // s.play();
    } catch (RemoteException e) {
    }
}

I should do more experiments to guess how it responds to different parameters and modes.

This process (reverse engineering) is normally what authors of an application don't want people do on their applications.

OBFUSCATE YOUR APPLICATION IF YOU DO MIND.

Two X11 bitmap fonts for Mac

2011-02-10T23:48:00.000+08:00

I came across these two X11 bitmap fonts, peep and neep-alt. I love what they looks in Linux, but their original sites don't provide MacOS counterparts. I used FontForge to generate their Mac dfont versions.

NeepAltBold
NeepAltMedium
NeepBold
NeepMedium
peepMedium

Use Emacs/JDEE in Android Development

2011-01-25T00:36:00.021+08:00

Eclipse/ADT is a great tool for Android development. But for people using Emacs, it is difficult to get used to it. Fortunately, JDEE is easy to be customized to work on Android development. Here are my settings on my MacBookPro,

;; Load JDEE
(require 'jde)

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(jde-global-classpath (quote ("~/android/out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/classes.jar" "~/android/out/target/common/obj/JAVA_LIBRARIES/core_intermediates/classes.jar" "~/android/out/target/common/obj/JAVA_LIBRARIES/services_intermediates/classes.jar" "~/android/out/out/target/common/obj/JAVA_LIBRARIES/android.policy_intermediates/classes.jar")))
 '(jde-jdk-registry (quote (("1.5.0" . "/System/Library/Frameworks/JavaVM.framework/Versions/1.5.0"))))
 '(jde-sourcepath (quote ("~/android/source/frameworks/base/services" "~/android/source/frameworks/base/core/java" "~/android/source/dalvik/libcore/luni/src/main/java")))

Here, I have android source code in ~/android/source and build in ~/android/out. If you are using SDK, you should add android.jar in SDK to jde-global-classpath. Also, you can put these settings into a per-project file prj.el in your project top directory for JDEE to load.

For example, my prj.el in one of my project looks like,

(jde-project-file-version "1.0")

;; Reset class path and source path
(jde-set-variables
 '(jde-project-name "openalarm-android")
 '(jde-gen-buffer-boilerplate
   '("/**"
     "*  OpenAlarm - an extensible alarm for Android"
     "*  Copyright (C) 2010 Liu Yen-Liang (Josh)"
     "*"
     "*"
     "*  This program is free software: you can redistribute it and/or modify"
     "*  it under the terms of the GNU General Public License as published by"
     "*  the Free Software Foundation, either version 3 of the License, or"
     "*  (at your option) any later version."
     "*"
     "*  This program is distributed in the hope that it will be useful,"
     "*  but WITHOUT ANY WARRANTY; without even the implied warranty of"
     "*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the"
     "*  GNU General Public License for more details."
     "*"
     "*  You should have received a copy of the GNU General Public License"
     "*  along with this program. If not, see ."
     "*/"))
 '(jde-log-max 5000)
 '(jde-enable-abbrev-mode t)
 ;; Class path for browsing files and generate code templates
 '(jde-global-classpath
   (quote ("$ANDROID_SDK_ROOT/platforms/android-7/android.jar"
           "$HOME/projects/openalarm-android/bin")))
 '(jde-sourcepath
   (quote ("$HOME/projects/openalarm-android/src"
           "$HOME/android/eclair_21/frameworks/base/core/java")
          ))
 '(jde-compile-option-directory "$HOME/projects/openalarm-android/bin") 
 '(jde-complete-function (quote jde-complete-menu)) 
 '(jde-run-working-directory "$HOME/projects/openalarm-android/bin")
 '(jde-help-docsets
   (quote (("Android SDK Doc" "$ANDROID_SDK_ROOT/docs/index.html" nil))))
 '(jde-build-function (quote (jde-ant-build)))
 '(jde-ant-args "-emacs")
 '(jde-ant-complete-target t)
 '(jde-ant-enable-find t) 
 '(jde-ant-read-args nil)
 '(jde-ant-read-buildfile nil)
 '(jde-ant-read-target nil)
 '(jde-ant-use-global-classpath nil)
 '(jde-ant-working-directory "$HOME/projects/openalarm-openalarm/bin/") 
 '(jde-built-class-path (quote ("$HOME/projects/openalarm-android/bin")))
 )

These settings enable us using method completion, source browsing, etc. But, I am still experimenting if we can build android target in JDEE.

For MacOS users: the environment variables must be defined in ~/.MacOSX/environemtn.plist

AppWidget design - Can I use my own custom widget?

2010-06-09T00:04:00.000+08:00

The answer to the question is probably no. But, not impossible. If you take a look at the design of AppWidget class family. You should know that a class that doesn't meet all requirements below can't be inflated in the layout of an AppWidget.

Annotated by RemoteViews
Can't be found by PathClassLoader with default class path - "."

The first one is simple because RemoteViews is not private interface. You can annotate your custom class by RemoteViews as Android widgets do.

The second one is not easy to attack. You need to know where this dot refers to. It is actually defined as an environment variable BOOTCLASSPATH in a file init.rc wrapped in your boot.img or ramdisk.img.

export BOOTCLASSPATH /system/framework/core.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/android.policy.jar:/system/framework/services.jar:/system/framework/org.startsmall.widget.jar

So, you need to,

Wrap your widget class in a jar library.

Archive classes.dex only.

Put your jar library into system.img.

The system.img can be decompressed by unyaffs. Decompress it and put jar library into system/framework.
Compress whole system/ directory back to system.img by mkyaffs2image.

Modify init.rc to add custom widget jar into BOOTCLASSPATH.

The boot.img/ramdisk.img is just a cpio archive. Decompress ramdisk.img, do modification to init.rc and archive it back as cpio file.

Put the system.img and ramdisk.img to your avd directory (~/.android/avd/avd-XXX). Start emulator and use logcat to see whether your custom jar library is loaded by Android.

Although you can use your custom widget class now, but you may soon find you can't actually use non-RemotableViews annotated method through RemoteViews set methods. Defeated? Not really, if you are willing to hack Android, I guess you still can modify Android source code to make RemotableMethod visible to your custom widget class.

If you don't want to do it, you need to make your custom widget self-handled. You can't update custom widgets by set methods of RemoteViews, but you can send broadcasts to update it because AppWidgetHostView instantiates custom widgets in your context.

You can see from above that it is possible to write custom widget class to be used in AppWidget design only when you have permissions to access image files. This means either you work for a phone company or you make custom ROMs.

Views that can be used along with RemoteViews

2010-05-24T13:10:00.000+08:00

Views must be annotated RemoteView in order to be used in the layout file inflated by LayoutInflater. Look into source code of RemoteViews. You can find an interface that is used to do annotation.

@Target({ ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
public @interface RemoteView {
}

And, for views that supports RemoteViews have RemoteView annotation in the beginning of their class definition. For example,

@RemoteView
public class LinearLayout extends ViewGroup {
 // ...
}

In the latest Android source, views that supports RemoteViews are,

AbsoluteLayout.java:40:@RemoteView
AnalogClock.java:39:@RemoteView
Button.java:58:@RemoteView
Chronometer.java:45:@RemoteView
FrameLayout.java:47:@RemoteView
ImageButton.java:71:@RemoteView
ImageView.java:55:@RemoteView
LinearLayout.java:44:@RemoteView
ProgressBar.java:123:@RemoteView
RelativeLayout.java:66:@RemoteView
TextView.java:186:@RemoteView
ViewFlipper.java:38:@RemoteView

Android UI Prototyping

2010-04-21T17:16:00.001+08:00

If you are from Qt world which has excellent Qt-designer served as a good prototyping tool since its early version, you probably are disappointed about the lack of prototyping tools in Android world.

We already has DroidDraw, but it still has a long way to go, though. I came across a website and it mentions Android GUI Prototyping that adds Android prototyping into your Visio template sets. I am not familiar with Visio and I normally use the primitive toolkit (pen, paper and glue) to do prototyping. I don't know if this Visio stuff works for you.

New release of OpenAlarm

2010-04-13T11:35:00.004+08:00

A new version of OpenAlarm is released at 04/15/2010. This version has several minor bug fixes and some UI changes.

Fixed FC when no default ringtone exists.
Fixed silent alarm if no ringtone specified (Play fallback ringtone instead).
Fallback to normal mode if user selects password mode but no password set.
Users can pull phone number directly from contact database in Phone alarms. The rule of picking a number to call is

Default phone number if exists.
First phone number.
No phone number for this person and show "no phone number" error message along with the name of this person.

Justify the position of the banner so that it is at the center of the screen.
Use hardware search button to apply another search to an filtered result is NOT allowed anymore.
Insert device information to the e-mail caused by the clicking on my email address in the About dialog.
UI changes. Move New menu item to the main screen.
Add explicit on/off settings to ToggleSwitch.

這個版本修正了一些小臭蟲以及使用者介面上的一些小改變。

修正當沒有預設響鈴時可能發生的強制關閉。
修正當沒有設定響鈴時的無聲鬧鈴。使用緊急鬧鈴。
如果使用者選擇密碼模式但忘記設定密碼，則使用正常模式。
在設定電話鬧鈴時，使用者可以直接從聯絡人清單挑選聯絡人。電話號碼的選擇順序為，

預設號碼。
第一組號碼。
無號碼時則顯示錯誤訊息。

對正OpenAlarm的Banner。
對搜尋出的鬧鐘再執行搜尋並無太大意義。關閉這個功能。
在關於此程式中，按我的email位址寄信給我，會在郵件中插入幾行除錯資訊。
使用者介面的稍許更動。將加入新鬧鈴的選單項目移到主畫面。
加入明確的開關設定。