Why is my android alarm manager firing instantly?

Question

I am following sample code for sending an update notification every 10'seconds. The code follows and it is in an UpdateService for an AppWidgetProvider. If I put a Thread.sleep(10*1000); I can see the expected behavior of my servicing loop. I obviously have something fundamentally wrong that is triggering immediately. It is supposed to be a PendingIntent of an alarm that will broadcast update to my listener.

long nextUpdate = 10*1000;
Log.d(TAG, "Requesting next update in " + nextUpdate + " msec." );

Intent updateIntent = new Intent(ACTION_UPDATE_ALL);
updateIntent.setClass(this, UpdateService.class);

PendingIntent pendingIntent = PendingIntent.getService(this, 0, updateIntent, 0);

// Schedule alarm, and force the device awake for this update
AlarmManager alarmManager = (AlarmManager)getBaseContext().getSystemService(Context.ALARM_SERVICE);
alarmManager.setRepeating(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime(), 
    nextUpdate, pendingIntent);

Answer 1

If you are creating PendingIntent of an alarm for past time it will be fired immediately. Example - Schedule alarm for today 8AM but executing code around 11AM will fire immediately.

Solution:

cal.add(Calendar.DATE, 1);

long delay = 24 * 60 * 60 * 1000;
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), delay,pendingIntent);` 

This will fire the event on next day at specified time (i.e 8AM);