Reset a variable on a specific time (also keep doing this after app restart)

Question

So I want a variable to reset to 0 at a specific time of day. I got this part working.

But every time the app restarts, the alarm stops working.

I got a “TimePicker” that gets a time from the user and then this method is called.

public void setAlarmResetDose(long timeInMillis) {
        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

    Intent intent = new Intent(this, AlarmResetTaken.class);

    PendingIntent pendingIntent = PendingIntent.getBroadcast(this,0,intent,0);

    alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, timeInMillis, AlarmManager.INTERVAL_DAY, pendingIntent);
}

That method above calls the class “AlarmResetTaken” which is a “BroadcastReciver” class that runs the code to reset the variable.

But like I said this only work as long as the app is running. When the app restarts, the alarm only starts working again when the user puts in a new time with the “TimePicker”.

My attempt to solve the problem

I used the code from the TimePicker and saved it in a variable:

timeDoseResetTotal = calendar.getTimeInMillis();

I also used sharedPreferences to save this time.

Then in the MainActivity onCreate i loaded the sharedPreferences value and ran the method “setAlarmResetDose(timeDoseResetTotal);” (with that value).

However this don’t seems to work.

Anyone got any ideas on how I could get this to work? :/

Edit:

I created this method and called it in MainActivity onCreate.

    public  void startAlarmBroadcastReceiver() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(
                calendar.get(Calendar.YEAR),
                calendar.get(Calendar.MONTH),
                calendar.get(Calendar.DAY_OF_MONTH),
                timeDoseResetHour,
                timeDoseResetHour,
                0

        );
        setAlarmResetDose(calendar.getTimeInMillis());

Where "timeDoseResetHour" and "timeDoseResetMin" are loaded with SharedPreferences fromearlier. It now works if the user opens the app before the time, but not after. So i guess if you re-open the app after the specific time it goes of the next day instead. Any ideas? :)

Answer 1

AlarmManager.setExactAndAllowWhileIdle appears to be the method you need. The tradeoff here is that you will need to reschedule this alarm each time it goes off.