He leído muchas preguntas y respuestas en Stackoverflow, y muchas de las cuales solo enfatizan en el.cancel() y la identificación única especial. Sin embargo, ahora importa cuántas veces lo intenté, simplemente no puedo cancelarlo.

Mi ID única

final static int RQS_1 = 1337;

Mi función setAlarm. pickTime es la Actividad actual, y timesUp, es otraService clase que muestra un brindis cuando se acaba el tiempo.

Intent intent = new Intent(pickTime.this, timesUp.class);
PendingIntent timesUpIntent = PendingIntent.getService(pickTime.this, RQS_1, intent, 0);
AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, targetCal.getTimeInMillis(),
                 timesUpIntent);
alarmManager.set(AlarmManager.RTC_WAKEUP, targetCal.getTimeInMillis(), timesUpIntent);

Mi función cancelAlarm

Intent intent = new Intent(this, pickTime.class);
PendingIntent timesUpIntent = PendingIntent.getBroadcast(this, RQS_1, intent, 0);
        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        if (timesUpIntent != null) {
            alarmManager.cancel(timesUpIntent);
            timesUpIntent.cancel();
            Toast.makeText(getApplicationContext(), "Alarm is cancelled",
                    Toast.LENGTH_SHORT).show();
                    } else {

            Toast.makeText(getApplicationContext(), "Unable to stop timer",
                    Toast.LENGTH_SHORT).show();
        }

Mis tiemposupServicio

public class timesUp extends Service {

    @Override
    public void onCreate() {

        // TODO Auto-generated method stub

        Toast.makeText(this, "MyAlarmService.onCreate()", Toast.LENGTH_LONG)
                .show();

    }

    @Override
    public IBinder onBind(Intent intent) {

        // TODO Auto-generated method stub

        Toast.makeText(this, "MyAlarmService.onBind()", Toast.LENGTH_LONG)
                .show();

        return null;

    }

    @Override
    public void onDestroy() {

        // TODO Auto-generated method stub

        super.onDestroy();

        Toast.makeText(this, "MyAlarmService.onDestroy()", Toast.LENGTH_LONG)
                .show();

    }

    @Override
    public void onStart(Intent intent, int startId) {

        // TODO Auto-generated method stub

        super.onStart(intent, startId);

        Toast.makeText(this, "MyAlarmService.onStart()", Toast.LENGTH_LONG)
                .show();

    }

    @Override
    public boolean onUnbind(Intent intent) {

        // TODO Auto-generated method stub

        Toast.makeText(this, "MyAlarmService.onUnbind()", Toast.LENGTH_LONG)
                .show();

        return super.onUnbind(intent);

    }

}