MyFirebaseMessagingService.kt

    private fun scheduleAlarm(
        scheduledTimeString: String?,
        title: String?,
        message: String?
    ) {
        val alarmMgr = applicationContext.getSystemService(Context.ALARM_SERVICE) as AlarmManager
        val alarmIntent =
            Intent(applicationContext, NotificationBroadcastReceiver::class.java).let { intent ->
                intent.putExtra(NOTIFICATION_TITLE, title)
                intent.putExtra(NOTIFICATION_MESSAGE, message)
                PendingIntent.getBroadcast(applicationContext, 0, intent, 0)
            }

        // Parse Schedule time
        val scheduledTime = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault())
            .parse(scheduledTimeString!!)

        scheduledTime?.let {
            // With set(), it'll set non repeating one time alarm.
            alarmMgr.set(
                AlarmManager.RTC_WAKEUP,
                it.time,
                alarmIntent
            )
        }
    }

    private fun showNotification(title: String, message: String) {
        NotificationUtil(applicationContext).showNotification(title, message)
    }