Question

I have onUpdate(…) metod of MyAppWidgetProvider class with the code:

...
Intent launchAppIntent = new Intent(context, SearchActivity.class);        
PendingIntent launchAppPendingIntent = PendingIntent.getActivity(context, 0, launchAppIntent, 0);        
remoteView.setOnClickPendingIntent(R.id.logo, launchAppPendingIntent);  
...

It works fine. New SearchActivity starts by clicking on widget. Now, I want to start on click not the SearchActivity, but an activity from the top of the stack of my task. For this purpose I change above code to:

ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(30);        
for (ActivityManager.RunningTaskInfo task:tasks) {
    if (task.baseActivity.getShortClassName().equals(".MainActivity")) {    
        try {
            Intent launchAppIntent = new Intent(context, Class.forName(task.topActivity.getClassName()));
            PendingIntent launchAppPendingIntent = PendingIntent.getActivity(context, 0, launchAppIntent, 0);        
            remoteView.setOnClickPendingIntent(R.id.logo, launchAppPendingIntent);                     
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(CashWidgetProvider.class.getName()).log(Level.SEVERE, null, ex);
        }                  
    }
}

that doesn’t work. Foreground activity in task stack doesn’t appear on monitor. Moreover, I don’t get any messages in log running this code.

However, the same code works fine being placed in some method of the class, inherited from Activity.

ActivityManager am = (ActivityManager) this.getSystemService(ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(30);        
for (ActivityManager.RunningTaskInfo task:tasks) {
    System.out.println(task.baseActivity.getShortClassName());
    if (task.baseActivity.getShortClassName().equals(".MainActivity")) {
        try {
            Intent launchAppIntent = new Intent(this, Class.forName(task.topActivity.getClassName())); 
            startActivity(launchAppIntent);
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(AbstractActivity.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
} 

How can I get it working for AppWidget!?

Answer 1

The problem appears due to misunderstanding of widget lifecycle, as usual… To get it working I have to create MyService class inherited from Service overriding onStart method with code:

...
Context context = this.getApplicationContext();
ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(30);        
for (ActivityManager.RunningTaskInfo task:tasks) {
    if (task.baseActivity.getShortClassName().equals(".MainActivity")) {    
        try {
            Intent launchTopIntent = new Intent(context, Class.forName(task.topActivity.getClassName()));
                context.startActivity(launchTopIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK));             
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(CashWidgetProvider.class.getName()).log(Level.SEVERE, null, ex);
        }                  
    }
} 
...

and call above MyService from AppWidgetProvider class by means of the code:

Intent launchAppIntent = new Intent(context, MyService.class);
launchAppIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, appWidgetIds);
PendingIntent launchAppPendingIntent = PendingIntent.getService(
            context.getApplicationContext(), 0, launchAppIntent, PendingIntent.FLAG_UPDATE_CURRENT);
remoteView.setOnClickPendingIntent(R.id.logo, launchAppPendingIntent2); 

Don’t forget to add this new service in AndroidManifest.xml under section

<application>
    ...
    <service android:name=".MyService"/>
</application>

P.S. Probably, it would be better to use BroadcastReceiver instead of Service.