Check Widget is Placed on Android Screen

Question

Can someone tell me how to check that my widget have been placed on the homescreen?

I have some code in my app that should run only if the widget is placed on the homescreen.

Answer 1

You need to store that information yourself. I usually use the application preferences, but you could use anything. Generally widgets use services to communicate, so your code that does stuff is likely in a service, but using the preference allows any portion of your app to access this.

In your widget class that extends AppWidgetProvider the onEnabled is called when the widget is put on a homescreen and the onDeleted is (usually) called when it's removed. onDisabled is called when all copies are removed.

So in the code of your widget provider:

@Override
public void onEnabled(Context context) {
    super.onEnabled(context);
    setWidgetActive(true);
    context.startService(new Intent(appContext, WidgetUpdateService.class));
}

@Override
public void onDisabled(Context context) {
    Context appContext = context.getApplicationContext();
    setWidgetActive(false);
    context.stopService(new Intent(appContext, WidgetUpdateService.class));
    super.onDisabled(context);
}

private void setWidgetActive(boolean active){
    Context appContext = context.getApplicationContext();
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(appContext);
    SharedPreferences.Editor edit = prefs.edit();
    edit.putBoolean(Constants.WIDGET_ACTIVE, active);
    edit.commit();
}

Elsewhere in code, you would check to see if the widget is active by:

public boolean isWidgetActive(Context context){
    Context appContext = context.getApplicationContext();
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
    return prefs.getBoolean(Constants.WIDGET_ACTIVE, false);
}