AlarmManager missing randomly when phone is not in use

I am calling a background

at interval of 30 min to read the latitude/longitude of current location and sending it to server by POST API .

I am using method of class to schedule alarm every 30 minutes. But some times the alarm is getting missed and service is not called. To monitor if alarm gets called or not in every 30 min I have generated Log.txt file in the sdcard. For every time alarm called the entry for the current time will be written in the Log.txt file. But after comparing 4 to 5 devices Log.txt files I noticed that for some of devices alarm is not calling method of (Background service) . Full code chunks mentioned below.

When app start method has been call which is below:

public static void registerUserTrackingReceiver(Context context) {

        try {

            Intent intent = new Intent(context, UserTrackingReceiver.class);



            boolean alarmUp = (PendingIntent.getService(context, 1001, intent, PendingIntent.FLAG_NO_CREATE) == null);



            if (alarmUp) {

                Calendar calendar = Calendar.getInstance();



                if (calendar.get(Calendar.MINUTE) > 0 && calendar.get(Calendar.MINUTE) <= 30) {

                    calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY));

                    calendar.set(Calendar.MINUTE, 30);

                    calendar.set(Calendar.SECOND, 0);

                } else if (calendar.get(Calendar.MINUTE) > 30) {

                    if (calendar.get(Calendar.HOUR_OF_DAY) == 23) {

                        calendar.set(Calendar.HOUR_OF_DAY, 0);

                    } else {

                        calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY) + 1);

                    }

                    calendar.set(Calendar.MINUTE, 0);

                    calendar.set(Calendar.SECOND, 0);

                } else {

                    calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY));

                    calendar.set(Calendar.MINUTE, 0);

                    calendar.set(Calendar.SECOND, 0);

                }



                PendingIntent sender = PendingIntent.getService(context, 1001, intent, 0);

                AlarmManager alarmManager = (AlarmManager) context.getSystemService(context.ALARM_SERVICE);

                alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),

                        AlarmManager.INTERVAL_HALF_HOUR, sender);

            }



        } catch (Exception e) {

            e.printStackTrace();

        }

}

UserTrackingReceiver.java is below:

public class UserTrackingReceiver extends Service

        implements LocationListener,

        GoogleApiClient.ConnectionCallbacks,

        GoogleApiClient.OnConnectionFailedListener {



    @Override

    public void onCreate() {

        super.onCreate();



        Calendar calendar = Calendar.getInstance();

        Util.appendLog("Tracking Alarm Called on: " + calendar.get(Calendar.HOUR_OF_DAY) + " : " + calendar.get(Calendar.MINUTE) + " : " + calendar.get(Calendar.SECOND));

        stopSelf();

    }

}

In Util.java there is method which is below:

public static void appendLog(String text) {



        String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();



        File logFile = new File(baseDir + "/" + Constant.AppNameSuper + "/log.txt");

        if (!logFile.exists()) {

            try {

                logFile.createNewFile();

            } catch (IOException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

        }

        try {

            //BufferedWriter for performance, true to set append to file flag

            BufferedWriter buf = new BufferedWriter(new FileWriter(logFile, true));

            buf.append(text);

            buf.newLine();

            buf.close();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

}

If alarm called every 30 min as per above code it should be written in Log.txt file in SDCARD. But the issue is it cannot write log file every 30 min that means alarm is missing. As per taking reading for two days I have noticed that alarm is not missing in day time as user continuously use their phone but it is missed in night when phone is not in use.

Out put log files with different devices are below:

Device A Log.txt

• Tracking Alarm Called on: 0 : 0 : 31(Start From 12:00 Night)


• Tracking Alarm Called on: 1 : 10 : 27


• Tracking Alarm Called on: 3 : 5 : 25


• Tracking Alarm Called on: 6 : 55 : 31


• Tracking Alarm Called on: 7 : 0 : 6


• Tracking Alarm Called on: 7 : 30 : 0


• Tracking Alarm Called on: 8 : 0 : 6


• Tracking Alarm Called on: 8 : 30 : 0


• Tracking Alarm Called on: 9 : 0 : 6


• Tracking Alarm Called on: 9 : 30 : 0


• Tracking Alarm Called on: 10 : 0 : 0

Device B Log.txt

• Tracking Alarm Called on: 0 : 0 : 27(Start From 12:00 Night)


• Tracking Alarm Called on: 0 : 30 : 1


• Tracking Alarm Called on: 1 : 0 : 1


• Tracking Alarm Called on: 1 : 30 : 2


• Tracking Alarm Called on: 2 : 0 : 1


• Tracking Alarm Called on: 2 : 30 : 1


• Tracking Alarm Called on: 3 : 0 : 1


• Tracking Alarm Called on: 3 : 30 : 1


• Tracking Alarm Called on: 4 : 0 : 1


• Tracking Alarm Called on: 4 : 30 : 29


• Tracking Alarm Called on: 5 : 0 : 1


• Tracking Alarm Called on: 5 : 30 : 2


• Tracking Alarm Called on: 6 : 0 : 30


• Tracking Alarm Called on: 6 : 30 : 1


• Tracking Alarm Called on: 7 : 0 : 1


• Tracking Alarm Called on: 7 : 30 : 1


• Tracking Alarm Called on: 8 : 0 : 1


• Tracking Alarm Called on: 8 : 30 : 1


• Tracking Alarm Called on: 9 : 0 : 32


• Tracking Alarm Called on: 9 : 30 : 1

Device C Log.txt

• Tracking Alarm Called on: 0 : 0 : 7(Start From 12:00 Night)


• Tracking Alarm Called on: 0 : 30 : 3


• Tracking Alarm Called on: 1 : 0 : 6


• Tracking Alarm Called on: 1 : 30 : 1


• Tracking Alarm Called on: 2 : 0 : 32


• Tracking Alarm Called on: 2 : 30 : 3


• Tracking Alarm Called on: 3 : 1 : 50


• Tracking Alarm Called on: 3 : 30 : 5


• Tracking Alarm Called on: 4 : 1 : 58


• Tracking Alarm Called on: 4 : 31 : 14


• Tracking Alarm Called on: 5 : 0 : 1


• Tracking Alarm Called on: 5 : 30 : 1


• Tracking Alarm Called on: 6 : 2 : 1


• Tracking Alarm Called on: 6 : 30 : 1


• Tracking Alarm Called on: 7 : 0 : 1


• Tracking Alarm Called on: 7 : 30 : 1


• Tracking Alarm Called on: 8 : 0 : 1


• Tracking Alarm Called on: 8 : 30 : 4


• Tracking Alarm Called on: 9 : 1 : 44


• Tracking Alarm Called on: 9 : 30 : 1

Device D Log.txt

• Tracking Alarm Called on: 0 : 1 : 25(Start From 12:00 Night)


• Tracking Alarm Called on: 0 : 30 : 0


• Tracking Alarm Called on: 1 : 31 : 41


• Tracking Alarm Called on: 2 : 39 : 52


• Tracking Alarm Called on: 3 : 0 : 25


• Tracking Alarm Called on: 3 : 30 : 58


• Tracking Alarm Called on: 4 : 0 : 25


• Tracking Alarm Called on: 4 : 30 : 56


• Tracking Alarm Called on: 5 : 30 : 51


• Tracking Alarm Called on: 7 : 18 : 55


• Tracking Alarm Called on: 7 : 30 : 0


• Tracking Alarm Called on: 8 : 0 : 25


• Tracking Alarm Called on: 8 : 30 : 43


• Tracking Alarm Called on: 9 : 0 : 3


• Tracking Alarm Called on: 9 : 30 : 25


• Tracking Alarm Called on: 10 : 0 : 25


• Tracking Alarm Called on: 10 : 30 : 4


• Tracking Alarm Called on: 11 : 1 : 52


• Tracking Alarm Called on: 11 : 30 : 27


• Tracking Alarm Called on: 12 : 1 : 6⁠⁠⁠⁠