@SuppressWarnings("MismatchedQueryAndUpdateOfCollection")
@SuppressLint("SimpleDateFormat")
public void setAlarm(int selectedHour, int selectedMinute)
{
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
    boolean isCalendar = prefs.getBoolean("isCalendar", false);
    if(!isCalendar)
        return;

    String startDate = prefs.getString("StartDate", "");

    Date mstartDate = null;
    SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss");
    String strStartDate = startDate + " " + String.valueOf(selectedHour) + ":" + String.valueOf(selectedMinute) + ":00";

    try
    {
        mstartDate = dateFormat.parse(strStartDate);
    }
    catch (ParseException e)
    {
        e.printStackTrace();
    }

    assert mstartDate != null;

    Date oneWeek = new Date(mstartDate.getTime() - 604800000L); // startDate - egy het
    Date oneDay = new Date(mstartDate.getTime() - 86400000L); // startDate - egy nap

    Calendar calStart = Calendar.getInstance(Locale.getDefault());
    Calendar calOneWeek = Calendar.getInstance(Locale.getDefault());
    Calendar calOneDay = Calendar.getInstance(Locale.getDefault());

    calStart.setTime(mstartDate);
    calOneWeek.setTime(oneWeek);
    calOneDay.setTime(oneDay);

    if(before(Calendar.getInstance(Locale.getDefault()),calOneWeek))
    {
        Intent weekIntent = new Intent(this, AlarmReceiver.class);
        weekIntent.putExtra("Type", "Week");
        weekIntent.putExtra("Date", startDate);
        AlarmManager alarmManager1 = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        alarmManager1.set(AlarmManager.RTC_WAKEUP, calOneWeek.getTimeInMillis(), PendingIntent.getBroadcast(this, 98, weekIntent, PendingIntent.FLAG_UPDATE_CURRENT));
    }
    if(before(Calendar.getInstance(Locale.getDefault()), calOneDay))
    {
        Intent dayIntent = new Intent(this, AlarmReceiver.class);
        dayIntent.putExtra("Type", "Day");
        dayIntent.putExtra("Date", startDate);
        AlarmManager alarmManager2 = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        alarmManager2.set(AlarmManager.RTC_WAKEUP, calOneDay.getTimeInMillis(), PendingIntent.getBroadcast(this, 99, dayIntent, PendingIntent.FLAG_UPDATE_CURRENT));
    }

    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    ArrayList<PendingIntent> intentArray = new ArrayList<>();

    ArrayList<TrainingDay> trainingDays = loadTraining();

    for(int i = 0; i < trainingDays.size(); ++i)
    {
        Date dayDate = null;
        Intent intent = new Intent(this, AlarmReceiver.class);
        intent.putExtra("Type", "Dayly");

        Calendar cal = Calendar.getInstance(Locale.getDefault());
        String dayTime = trainingDays.get(i).getDate() + " " + String.valueOf(selectedHour) + ":" + String.valueOf(selectedMinute) + ":00";
        try
        {
            dayDate = dateFormat.parse(dayTime);
        }
        catch (ParseException e)
        {
            e.printStackTrace();
        }

        cal.setTime(dayDate);

        PendingIntent pendingIntent = PendingIntent.getBroadcast(this, i, intent, PendingIntent.FLAG_UPDATE_CURRENT);

        alarmManager.set(AlarmManager.RTC_WAKEUP,
            cal.getTimeInMillis(),
            pendingIntent);

        intentArray.add(pendingIntent);
    }

    isNotifActive = true;
}

És a Receiver:

@Override
public void onReceive(Context context, Intent intent)
{
    String type = intent.getStringExtra("Type");
    String date = intent.getStringExtra("Date");
    switch (type)
    {
    case "Week":
        createNotification(context, "Women's Run", "Ihr Training startet am " + date + "!", "Alert");
        break;
    case "Day":
        createNotification(context, "Women's Run", "Morgen startet Ihr Trainingsplan!", "Alert");
        break;
    case "Dayly":
        createNotification(context, "Women's Run", "Heute steht ein Training an!", "Alert");
        break;
    }
}

public void createNotification(Context context, String msg, String msgText, String msgAlert)
{
    PendingIntent notificIntent = PendingIntent.getActivity(context,0, new Intent(context, SplashActivity.class),0);
    NotificationCompat.Builder builder = new NotificationCompat.Builder(context)
        .setSmallIcon(R.mipmap.ic_launcher)
        .setContentTitle(msg)
        .setTicker(msgAlert)
        .setContentText(msgText);


    builder.setContentIntent(notificIntent);
    builder.setDefaults(NotificationCompat.DEFAULT_SOUND);
    builder.setAutoCancel(true);

    NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.notify(1, builder.build());
}