Android AlarmManager not working on some devices when the app is closed

Question

I am trying to run IntentService as such from AlarmManager setRepeating() for every half an hour. I want to send a to broadcast, from broad cast to intent service. In the service, some functionality will be done.

But, initially the AlarmManager in not triggering while the app is in closed state.

When my app is running or in background state the alarm is working fine and when I close the app the alarm is not working in some devices.

What should I do to run the alarm even if the app is closed?

Answer 1

From the documentation of setRepeating():

As of API 19, all repeating alarms are inexact.

Moreover, setRepeating() does not work with Doze.

You should use exact alarms (set by the appropriate AlarmManager method based on the API level of the device):

if (Build.VERSION.SDK_INT >= 23) {     alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP,             triggerTime, pendingIntent); } else if (Build.VERSION.SDK_INT >= 19) {     alarmManager.setExact(AlarmManager.RTC_WAKEUP, triggerTime, pendingIntent); } else {     alarmManager.set(AlarmManager.RTC_WAKEUP, triggerTime, pendingIntent); } 

And reschedule them every time they fire.

For the rescheduling you could add the original trigger time to the Intent:

intent.putExtra(KEY_TRIGGER_TIME, triggerTime); 

Then retrieve this extra in onReceive(), add your desired interval to it and reschedule the alarm using the new value:

@Override public void onReceive(Context context, Intent intent) {     long triggerTime = intent             .getLongExtra(KEY_TRIGGER_TIME, System.currentTimeMillis());      // adding one day to the current trigger time     triggerTime += TimeUnit.DAYS.toMillis(1);      // set a new alarm using the new trigger time     // ... } 

NOTE: As @Opiatefuchs mentioned in the comment above, some manufacturers (such as Xiaomi or Huawei) may implement certain battery saver functions that can prevent alarms from being fired and cannot be bypassed programmatically.