Android: Get all PendingIntents set with AlarmManager

To cancel an alarm you need to re-create the same PendingIntent and pass the same request code.

So, I have created an AlarmUtils to help me saving all the request codes in the preferences to cancel it in the future if it is needing. All you need is to use the following class and call the following methods:

• addAlarm to add a new alarm and pass a request code.
• cancelAlarm to remove an alarm, you need to re-create the same
  Intent and pass the same request code.
• hasAlarm to verify if that alarm as added, you need to re-create the same Intent and pass the same request code.
• cancelAllAlarms to remove ALL alarms setted.

My AlarmUtils

public class AlarmUtils {

    private static final String sTagAlarms = ":alarms";

    public static void addAlarm(Context context, Intent intent, int notificationId, Calendar calendar) {

        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, notificationId, intent, PendingIntent.FLAG_CANCEL_CURRENT);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
        } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            alarmManager.setExact(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
        } else {
            alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
        }

        saveAlarmId(context, notificationId);
    }

    public static void cancelAlarm(Context context, Intent intent, int notificationId) {
        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, notificationId, intent, PendingIntent.FLAG_CANCEL_CURRENT);
        alarmManager.cancel(pendingIntent);
        pendingIntent.cancel();

        removeAlarmId(context, notificationId);
    }

    public static void cancelAllAlarms(Context context, Intent intent) {
        for (int idAlarm : getAlarmIds(context)) {
            cancelAlarm(context, intent, idAlarm);
        }
    }

    public static boolean hasAlarm(Context context, Intent intent, int notificationId) {
        return PendingIntent.getBroadcast(context, notificationId, intent, PendingIntent.FLAG_NO_CREATE) != null;
    }

    private static void saveAlarmId(Context context, int id) {
        List<Integer> idsAlarms = getAlarmIds(context);

        if (idsAlarms.contains(id)) {
            return;
        }

        idsAlarms.add(id);

        saveIdsInPreferences(context, idsAlarms);
    }

    private static void removeAlarmId(Context context, int id) {
        List<Integer> idsAlarms = getAlarmIds(context);

        for (int i = 0; i < idsAlarms.size(); i++) {
            if (idsAlarms.get(i) == id)
                idsAlarms.remove(i);
        }

        saveIdsInPreferences(context, idsAlarms);
    }

    private static List<Integer> getAlarmIds(Context context) {
        List<Integer> ids = new ArrayList<>();
        try {
            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
            JSONArray jsonArray2 = new JSONArray(prefs.getString(context.getPackageName() + sTagAlarms, "[]"));

            for (int i = 0; i < jsonArray2.length(); i++) {
                ids.add(jsonArray2.getInt(i));
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return ids;
    }

    private static void saveIdsInPreferences(Context context, List<Integer> lstIds) {
        JSONArray jsonArray = new JSONArray();
        for (Integer idAlarm : lstIds) {
            jsonArray.put(idAlarm);
        }

        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString(context.getPackageName() + sTagAlarms, jsonArray.toString());

        editor.apply();
    }
}

You need to create your pending intent and then cancel it

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

    Intent updateServiceIntent = new Intent(context, MyPendingIntentService.class);
    PendingIntent pendingUpdateIntent = PendingIntent.getService(context, 0, updateServiceIntent, 0);

    // Cancel alarms
    try {
        alarmManager.cancel(pendingUpdateIntent);
    } catch (Exception e) {
        Log.e(TAG, "AlarmManager update was not canceled. " + e.toString());
    }

You don't have to keep reference to it. Just define a new PendingIntent like exactly the one that you defined in creating it.

For example:

if I created a PendingIntent to be fired off by the AlarmManager like this:

Intent alarmIntent = new Intent(getApplicationContext(), AlarmBroadcastReceiver.class);
alarmIntent.setData(Uri.parse("custom://" + alarm.ID));
alarmIntent.setAction(String.valueOf(alarm.ID));
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);

PendingIntent displayIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, alarmIntent, 0);

alarmManager.set(AlarmManager.RTC_WAKEUP, alarmDateTime, displayIntent);

Then somewhere in your other code (even another activity) you can do this to cancel:

Intent alarmIntent = new Intent(getApplicationContext(), AlarmBroadcastReceiver.class);
alarmIntent.setData(Uri.parse("custom://" + alarm.ID));
alarmIntent.setAction(String.valueOf(alarm.ID));
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);

PendingIntent displayIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, alarmIntent, 0);

alarmManager.cancel(displayIntent);

The important thing here is to set the PendingIntent with exactly the same data and action, and other criteria as well as stated here http://developer.android.com/reference/android/app/AlarmManager.html#cancel%28android.app.PendingIntent%29