Question

I need my Service to do tasks every night at 02:00, and if failed in task then schedule itself to start again after 30min, but if succeeded then stop itself and start again the other night at 02:00. I managed to get it start at 02:00 but after it is triggered it just triggeres itself continiously.

My code is in Service, and here is the code itself:

@Override
    public void onStart(Intent intent, int startId) {
        super.onStart(intent, startId);

        //doTasks();

        MediaPlayer player = MediaPlayer.create(this,
                Settings.System.DEFAULT_NOTIFICATION_URI);
        player.start();

        AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
        alarmManager.cancel(pendingIntent);
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.HOUR_OF_DAY, 2);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),AlarmManager.INTERVAL_DAY, pendingIntent);
    }

doTasks() is the tasks I need to run but because they are slow I use notification sound for testing purposes. And pendingIntent is this Service itself.

Any ideas what is it that makes my AlarmManager trigger constantly?

Answer 1

If your pendingIntent is set to start the Service then basically you’re repeatedly creating a new alarm each time in the onStart(...) method.

AlarmManager has a mechanism where it will trigger an alarm “late” if the device was asleep when it should have triggered. In your case, because you constantly re-create the alarm, AlarmManager constantly thinks it should be triggered immediately even if the time is past 02:00:00.

Create the alarm somewhere else to prevent it being constantly re-created each time the Service starts.