Alarm manager is not working with long term tasks

Question

My Alarm manager is working when I set the Alarm, after 2 or 3 minutes. But when I set Alarm for a day after or after 30 minutes it doesn't rings.

Main Activity :

    addTaskIMBTN.setOnClickListener {

        val dialog: AlertDialog.Builder = AlertDialog.Builder(this)
        val view: View = layoutInflater.inflate(R.layout.dialog_task, null)

        //time picker and date picker
        val timepicker: Button = view.findViewById(R.id.timeSelector)
        val datePicker: Button = view.findViewById(R.id.dateSelector)
        val deadlineTXT: TextView = view.findViewById(R.id.dateTimeShower)
        val deadtimeTXT: TextView = view.findViewById(R.id.timeShower)

        todoName = view.findViewById(R.id.taskET2)

        val hour = c.get(Calendar.HOUR_OF_DAY)
        val minute = c.get(Calendar.MINUTE)

        timepicker.setOnClickListener {
            timePickerDialog =
                TimePickerDialog(
                    this,
                    { _, p1, p2 ->
                        c.set(Calendar.HOUR_OF_DAY, p1)
                        c.set(Calendar.MINUTE, p2)
                        c.set(Calendar.SECOND, 0)
                        deadtimeTXT.text = "Time : $p1:$p2"


                    }, hour, minute, true
                )
            timePickerDialog.show()
        }
        val mYear = c.get(Calendar.YEAR)
        val mMonth = c.get(Calendar.MONTH)
        val mDay = c.get(Calendar.DAY_OF_MONTH)

        datePicker.setOnClickListener {
            datePickerDialog = DatePickerDialog(
                this,
                { _: DatePicker, year, monthOfYear, dayOfMonth ->
                    deadlineTXT.text =
                        "Date : " + dayOfMonth.toString() + "-" + (monthOfYear + 1) + "-" + year
                    c.set(Calendar.YEAR, year)
                    c.set(Calendar.DAY_OF_MONTH, dayOfMonth)
                    c.set(Calendar.MONTH, monthOfYear)
                },
                mYear,
                mMonth,
                mDay
            )
            datePickerDialog.show()
        }

        //positive button function
        dialog.setView(view)
        dialog.setTitle("Add a Task")
        dialog.setPositiveButton("Add") { _: DialogInterface, _: Int ->
            if (todoName.toString().isEmpty() || todoName.text.isEmpty()) {
                Toast.makeText(
                    applicationContext,
                    "Please add a name for the task",
                    Toast.LENGTH_LONG
                ).show()
            } else {
                Log.i("today's time", c.time.toString())

                val simpleDateFormat = SimpleDateFormat("d MMM 'at' HH:mm")
                date = c.time
                val string = simpleDateFormat.format(date)
                val newInt : Int = c.timeInMillis.toInt()

                val intent : Intent = Intent(this@TasksActivity, ReminderBroadcast::class.java )
                val pendingIntent = PendingIntent.getBroadcast(this@TasksActivity, newInt, intent, PendingIntent.FLAG_UPDATE_CURRENT)

                val alarmManager : AlarmManager = getSystemService(ALARM_SERVICE) as AlarmManager
                alarmManager.setExact(AlarmManager.RTC_WAKEUP, c.timeInMillis, pendingIntent)

                tdItem.itemName = todoName.text.toString()
                tdItem.isCreatedAt = string
                tdItem.toDoId = todoID
                tdItem.isCompleted = false
                dbHandler.addTasks(tdItem)
                refreshList()
            }
        }
        dialog.setNegativeButton("Cancel") { _: DialogInterface, _: Int ->

        }
        dialog.show()
    }

    backBTN.setOnClickListener {
        finish()
    }
}

Notification Channel :

fun notificationChannel(){
    val uri  = Uri.parse("android.resource://" + this.packageName + "/" + R.raw.checked_it)

    val audioAttributes = AudioAttributes.Builder()
        .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
        .setUsage(AudioAttributes.USAGE_ALARM)
        .build()

    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
        val name : CharSequence = "NotifyMeForDeadline";
        val description : String = "Channel for Deadline Reminder"
        val importance = NotificationManager.IMPORTANCE_HIGH
        val nc : NotificationChannel = NotificationChannel("notifyDeadline", name, importance)
        nc.setSound(uri, audioAttributes)
        nc.description = description

        val notificationManager = getSystemService(NotificationManager::class.java)
        notificationManager.createNotificationChannel(nc)
    }
}

Broadcast Reciever :

override fun onReceive(p0: Context, p1: Intent) {
    p0.startActivity(p1)
    val intent : Intent = Intent(p0, TasksActivity::class.java)
    val pendingIntent = PendingIntent.getActivity(p0, 0, intent, PendingIntent.FLAG_ONE_SHOT)
    val uri  = Uri.parse(Uri.parse("android.resource://" + p0.packageName + "/" + R.raw.checked_it)
        .toString())
    Toast.makeText(p0, "Recieved", Toast.LENGTH_LONG).show()
    val builder : NotificationCompat.Builder = NotificationCompat.Builder(p0, "notifyDeadline")
        .setSmallIcon(R.drawable.ic_baseline_alarm_24)
        .setContentTitle("Reminder from Checked-It")
        .setContentText("Hey, are you working on your tasks or just procrastinating?")
        .setPriority(NotificationCompat.PRIORITY_HIGH)
        .setSound(uri)
        .setContentIntent(pendingIntent)

    val notificationManagerCompat = NotificationManagerCompat.from(p0)
    notificationManagerCompat.notify((((Date().getTime() / 1000L) % Integer.MAX_VALUE).toInt()), builder.build())

}

I can find the solution for this so please help me out....I'll be pleased to listen your answer. Thank You!!

And Notification also doesn't show up when after scheduling the task I open the app again.

Answer 1

Here is a working sample of the Alarm Manager. This example works consistently for as long as you need it to.

How to use Android AlarmManager in Fragment in Kotlin?

Since all alarms are cancelled on reboot. You will also need to handle Device Reboot with Broadcast receivers. You can find more information on the internet.

In addition to that, here is a working sample of Max Priority Notifications:

private fun sendInternetDaysLeftNotification(context: Context) {
        // This is used for opening application when the notification is clicked
        val intent: Intent = Intent(context, ProfileActivity::class.java)
            .putExtra(INTENT_EXTRA_INTERNET_DAYS_LEFT, contentText)
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
        intent.action = INTENT_ACTION_INTERNET_DAYS_LEFT_DIALOG
        val pendingIntent: PendingIntent = PendingIntent.getActivity(
            context,
            0,
            intent,
            PendingIntent.FLAG_UPDATE_CURRENT
        )

        val channelId: String = context.resources.getString(R.string.internetDaysLeftNotificationsChannelId)
        val defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION)
        val notificationBuilder: NotificationCompat.Builder = NotificationCompat.Builder(context, channelId)
            .setSmallIcon(R.drawable.ic_notification)
            .setContentTitle(contentTitle)
            .setContentText(contentText)
            .setAutoCancel(true)
            .setContentIntent(pendingIntent)
            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
            .setPriority(NotificationCompat.PRIORITY_MAX)

        val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(channelId, DEFAULT_NOTIFICATION_CHANNEL_NAME, NotificationManager.IMPORTANCE_HIGH)
            notificationManager.createNotificationChannel(channel)
        }

        notificationManager.notify(Random.nextInt(0, 100), notificationBuilder.build())
    }