Question

I’m trying to implement an Android app that needs to alarm (or to alert) multiple times along the time.

I’ve already searched, but the nearest I found was a fixed-number of alarms set, and I guess the example didn’t work.

What I want to know if there is exists an approach to dynamically set multiple alarms, like an Array of alarms and then to trigger those alarms in their specific timestamps.

Answer 1

If you want to set multiple alarms (repeating or single), then you just need to create their PendingIntents with different requestCode. If requestCode is the same, then the new alarm will overwrite the old one.

Here is the code to create multiple single alarms and keep them in ArrayList. I keep PendingIntent‘s in the array because that’s what you need to cancel your alarm.

// context variable contains your `Context`
AlarmManager mgrAlarm = (AlarmManager) context.getSystemService(ALARM_SERVICE);
ArrayList<PendingIntent> intentArray = new ArrayList<PendingIntent>();

for(i = 0; i < 10; ++i)
{
   Intent intent = new Intent(context, OnAlarmReceiver.class);
   // Loop counter `i` is used as a `requestCode`
   PendingIntent pendingIntent = PendingIntent.getBroadcast(context, i, intent, 0);
   // Single alarms in 1, 2, ..., 10 minutes (in `i` minutes)
   mgrAlarm.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 
                SystemClock.elapsedRealtime() + 60000 * i, 
                pendingIntent); 

   intentArray.add(pendingIntent);
}

Also, see this question: How to set more than one alarms at a time in android?.