以编程方式更改Android小部件的ImageButton的src图像

Question

I am developing an Android app with a homescreen widget, which is an imageButton, and i want the image of the button to change after its been pressed. I have tried selector in an xml file, to change the image of the button, but it changes it only when it is pressed, but it goes back when its released.

I want it to change image after it was pressed and when the code inside the WidgetProvider is executed, it changes the image back to the default one.

I tried to do it programatically(in onRecieve() method), I guess it should be something with RemoteViews but whatever i try, it doesnt work.

Could someone help my with this? I saw many people asking about it, but most of the posts were either pretty old or the solutions were not working for me.

Thank you :)

Answer 1

Normally you'd set the image on the surface of the ImageButton using the setImageResource method ( ImageButton inherits it from ImageView ), but that method isn't available for RemoteViews .

RemoteViews offers a corresponding setImageViewResource method that does what you want (as well as setImageViewBitmap and setImageViewUri depending on how you'd like to provide the image data).

The code to set the image (say, within your BroadcastReceiver's onReceive method) would look something like this:

@Override
public void onReceive(Context context, Intent intent) {
    int appWidgetId = intent.getIntExtra("appWidgetId", -1);    
    RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.main);
    views.setImageViewResource(R.id.imageButton1, R.drawable.awesome_image);
    AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
    appWidgetManager.updateAppWidget(appWidgetId, views);
}

Note that the code above assumes you've added the id of the widget to be manipulated as an extra to the broadcast intent (wrapped in a PendingIntent that is sent when the user clicks the ImageButton) using the key "appWidgetId". You'll most likely want to do that in the onUpdate method of your AppWidgetProvider, like so:

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
    for (int i = 0; i < appWidgetIds.length; i++) {
        int appWidgetId = appWidgetIds[i];
        Intent intent = new Intent ("YourActionHere");
        intent.putExtra("appWidgetId", appWidgetId);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, i, intent, 0);

        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.main);
        views.setImageViewResource(R.id.imageButton1, R.drawable.initial_image);

        views.setOnClickPendingIntent(R.id.imageButton1, pendingIntent);
        appWidgetManager.updateAppWidget(appWidgetId, views);
    }
}

Answer 2

A simple but not elegant way is:

 boolean isButtonSelected = false;

    ..
 button.setOnClickListener(buttonListener);

    ..

 OnClickListener buttonListener = new OnClickListener() {
  @Override
  public void onClick(View arg0) {

      if(isButtonSelected ){
          isButtonSelected = false;
          button.setBackgroundResource(R.drawable.buttonOff);  // or setImageResource(..);
      } else{
          isButtonSelected = true;
          button.setBackgroundResource(R.drawable.buttonOn);
      }
   }
 };