How to build a Simple Android Widget

Question

So I have a bit of experience building android applications. But now i would like to build a widget for android that would sit on the home screen and display a button, and when the button is pressed it plays a sound. I've been looking at tutorials online on how to set up an android widget but i cant seem to figure it out. Are there any good tutorials out there on how to make a standalone widget this simple or somewhere i can start? Thanks in advance, Peter

Answer 1

first Create a new layout file inside res/layout, under the project structure, that will define the widget layout (widgetlayout.xml) according to the following structure.

<TextView android:text="@string/widgettext" 
              android:layout_width="0dp"
              android:layout_height="wrap_content"
              android:layout_weight="0.8"
              android:layout_gravity="center_vertical"
              android:textColor="#000000"></TextView>
<TextView android:text="@string/widgetmoodtext"
              android:id="@+id/widgetMood" android:layout_width="0dp" 
              android:layout_height="wrap_content" 
              android:layout_weight="0.3" 
              android:layout_gravity="center_vertical" 
              android:textColor="#000000"></TextView>
<ImageButton android:id="@+id/widgetBtn" 
             android:layout_width="0dp" 
             android:layout_height="wrap_content" 
             android:layout_weight="0.5"  
             android:src="@drawable/smile_icon" 
             android:layout_gravity="center_vertical">
 </ImageButton>

Create the res/xml folder under the project structure Create a xml file (widgetproviderinfo.xml) with the following parameters:

 <appwidget-provider
           xmlns:android="http://schemas.android.com/apk/res/android" 
           android:minWidth="220dp" 
           android:minHeight="72dp"
           android:updatePeriodMillis="86400000" 
           android:initialLayout="@layout/widgetlayout">
       </appwidget-provider>

Now you should create the service that reacts to the user interaction with the smiley image button (CurrentMoodService.java).

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    super.onStart(intent, startId);
            updateMood(intent);
    stopSelf(startId);
    return START_STICKY;
}

private void updateMood(Intent intent) {
       if (intent != null){
        String requestedAction = intent.getAction();
        if (requestedAction != null &&  requestedAction.equals(UPDATEMOOD)){
            this.currentMood = getRandomMood();
            int widgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, 0);
            AppWidgetManager appWidgetMan = AppWidgetManager.getInstance(this);
            RemoteViews views = new RemoteViews(this.getPackageName(),R.layout.widgetlayout);
            views.setTextViewText(R.id.widgetMood, currentMood);
            appWidgetMan.updateAppWidget(widgetId, views);  
        }
       }
   }

After defining the service, it is time to implement the widget provider class (CurrentMoodWidgetProvider.java).

    @Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
        int[] appWidgetIds) {
    super.onUpdate(context, appWidgetManager, appWidgetIds);

    for (int i=0; i<appWidgetIds.length; i++) {
        int appWidgetId = appWidgetIds[i];
        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widgetlayout);
        Intent intent = new Intent(context, CurrentMoodService.class);
        intent.setAction(CurrentMoodService.UPDATEMOOD);
        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
        PendingIntent pendingIntent = PendingIntent.getService(context, 0, intent, 0);
        views.setOnClickPendingIntent(R.id.widgetBtn, pendingIntent);
        appWidgetManager.updateAppWidget(appWidgetId, views);
    }
}   

Finally it is necessary to declare the Service and the AppWidgetProvider in the Manifest (AndroidManifest.xml).

    <service android:name=".CurrentMoodService">
    </service>
<receiver android:name=".CurrentMoodWidgetProvider">
    <intent-filter>
        <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
    </intent-filter>
    <meta-data android:name="android.appwidget.provider"
               android:resource="@xml/widgetproviderinfo" />
</receiver>

and if you want to download the whole source code then have a look at the url below...

http://sites.google.com/site/androidsourcecode/src/CurrentMoodWidgetProject.rar?attredirects=0