How to set an alarm to repeat 3 time every day ?

Question

I want to set an alarm to check the server for getting new data everyday at 7 AM , 12 AM and 10 PM.
I tried this way :

 public void startAlarm(Context context) {
        AlarmManager alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Intent intent = new Intent(context, ShowNotificationReceiver.class);
        PendingIntent alarmIntent = PendingIntent.getBroadcast(context, REQUEST_CODE, intent, PendingIntent.FLAG_CANCEL_CURRENT);


        Calendar firstTurn = Calendar.getInstance();
        Calendar secondTurn = Calendar.getInstance();
        Calendar thirdTurn = Calendar.getInstance();

        // set times
        firstTurn.set(Calendar.HOUR_OF_DAY,FIRST_TURN_HOUR);
        firstTurn.set(Calendar.MINUTE,FIRST_TURN_MINUTE);
        secondTurn.set(Calendar.HOUR_OF_DAY,SECOND_TURN_HOUR);
        secondTurn.set(Calendar.MINUTE,SECOND_TURN_MINUTE);
        thirdTurn.set(Calendar.HOUR_OF_DAY,THIRD_TURN_HOUR);
        thirdTurn.set(Calendar.MINUTE,THIRD_TURN_MINUTE);

        alarmMgr.cancel(alarmIntent);
        alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, firstTurn.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);
        alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, secondTurn.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);
        alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, thirdTurn.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);
    }  

If i comment 2 last line its work correctly and fire in time , but it doesnt work if i want all of them .
Where is my mistake and how can i fix this ?

Answer 1

If you simply want it to repeat three times a day you can register it to trigger every 8th hour (As 24 hours divided by 8 is 3).

alarmMgr.setInexactRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTurn.getTimeInMillis(), AlarmMAnager.INTERVAL_HOUR * 8, alarmIntent);

The reason your code isn't working is because any call to setInexactRepeating will cancel any previous call with an identical PendingIntent. From the documentation :

If there is already an alarm scheduled for the same IntentSender, it will first be canceled.

If you want to perform the operation three times a day but not at every 8th hour, you could instead trigger one alarm at the first turn using AlarmManager.setExact() (ie, without repeat). Once that alarm is triggered (ie, onReceive() is called in your receiver) you simply call AlarmManager.setExact() with the second turn and so on.

Answer 2

After some search and playing more with code i resolve my problem in this way :

public void startAlarm(Context context) {

        AlarmManager alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        Intent intent = new Intent(context, ShowNotificationReceiver.class);

        Calendar firstTurn = Calendar.getInstance();
        Calendar secondTurn = Calendar.getInstance();
        Calendar thirdTurn = Calendar.getInstance();

        // set times
        firstTurn.set(Calendar.HOUR_OF_DAY, FIRST_TURN_HOUR);
        firstTurn.set(Calendar.MINUTE, FIRST_TURN_MINUTE);
        PendingIntent alarmIntent = PendingIntent.getBroadcast(context, REQUEST_CODE, intent, PendingIntent.FLAG_CANCEL_CURRENT);


        secondTurn.set(Calendar.HOUR_OF_DAY, SECOND_TURN_HOUR);
        secondTurn.set(Calendar.MINUTE, SECOND_TURN_MINUTE);
        PendingIntent alarmIntent2 = PendingIntent.getBroadcast(context, REQUEST_CODE2, intent, PendingIntent.FLAG_CANCEL_CURRENT);


        thirdTurn.set(Calendar.HOUR_OF_DAY, THIRD_TURN_HOUR);
        thirdTurn.set(Calendar.MINUTE, THIRD_TURN_MINUTE);
        PendingIntent alarmIntent3 = PendingIntent.getBroadcast(context, REQUEST_CODE3, intent, PendingIntent.FLAG_CANCEL_CURRENT);

        alarmMgr.cancel(alarmIntent);
        alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, firstTurn.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent);
        alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, secondTurn.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent2);
        alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP, thirdTurn.getTimeInMillis(), AlarmManager.INTERVAL_DAY, alarmIntent3);
    }

As explained in this answer

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.

Answer 3

Try to create 3 different AlarmManager objects for your approach. Also, you could instead trigger each alarm after the end of another alarm, inside your BroadcastReceiver