Notification in Android Studio Not Coming on Time

Question

I am currently developing an app on android studio using java where I want the user to be able to receive notifications from calendar events that they create. However, my notifications are not coming on time as they are either lagging or just not showing.

Here is my coding for the alarm receiver which sets up the notification:

public class AlarmReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        String event = intent.getStringExtra("event");
        String time = intent.getStringExtra("time");
        int notId = intent.getIntExtra("id", 0);
        Intent activityIntent = new Intent(context, CalendarActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, activityIntent, PendingIntent.FLAG_ONE_SHOT);

        String channelId = "channel_id";
        CharSequence name = "channel_name";
        String description = "description";
        NotificationChannel channel = new NotificationChannel(channelId, name, NotificationManager.IMPORTANCE_HIGH);
        channel.setDescription(description);
        NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
        notificationManager.createNotificationChannel(channel);

        Notification notification = new NotificationCompat.Builder(context, channelId)
                .setSmallIcon(R.drawable.ic_launcher_foreground)
                .setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))
                .setContentTitle(event)
                .setContentText(time)
                .setDeleteIntent(pendingIntent)
                .setGroup("Group_calendar_view")
                .build();
        NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(context);
        notificationManagerCompat.notify(notId,notification);
    }
}

Here is my CustomCalendarView Activity that sets up the alarm:

private void setAlarm(Calendar calendar, String event, String time, int RequestCode){
        Intent intent = new Intent(context.getApplicationContext(), AlarmReceiver.class);
        intent.putExtra("event",event);
        intent.putExtra("time",time);
        intent.putExtra("id",RequestCode);
        @SuppressLint("UnspecifiedImmutableFlag") PendingIntent pendingIntent = PendingIntent.getBroadcast(context,RequestCode,intent,PendingIntent.FLAG_ONE_SHOT);
        AlarmManager alarmManager = (AlarmManager)context.getApplicationContext().getSystemService(Context.ALARM_SERVICE);
        alarmManager.set(AlarmManager.RTC_WAKEUP,calendar.getTimeInMillis() ,pendingIntent);
    }

For example: When I set an alarm for 10:20 am, the notification either doesn't pop up or pops up really late like at 10:22 am. Please help. Let me know if I need to provide any more information.

Answer 1

You should use exact alarms for firing alarm on time,

use alarmManager.setExact() instead of alarmManager.set().

setExact() method is like set(), but does not permit the OS to adjust the delivery time. The alarm will be delivered as nearly as possible to the requested trigger time.

Answer 2

Put setExact() instead of set

alarmManager.setExact(...);

But with different devices and interface updates, the performance of the application work differed from one device to another, in this case you must put some settings in your application such as Disable Software Battery Optimizations, make the application run in the background even after closing, give Permissions Autostart, turn on all notifications and display them etc. Finally, call the functions in the onStop () event of the Activity .

Answer 3

Yes, correct. You should ask user to allow Battery Optimization and in Android 12 or higher you should ask user to enable Alarms & Reminders permission as well.

But, when your app wants to fire alarms exactly on time you have to use exact alarms.