basic notification

MainActivity.kt

package com.ytapps.myapplication

import android.Manifest
import android.app.Notification
import android.app.NotificationChannel
import android.app.NotificationManager
import android.content.Context
import android.content.pm.PackageManager
import android.os.Build
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import androidx.core.app.NotificationCompat
import kotlin.random.Random

class MainActivity : AppCompatActivity() {
    val CHANNEL_ID = "ch"

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
        createNotificationChannel(manager)

        if (ActivityCompat.checkSelfPermission(
                this@MainActivity,
                Manifest.permission.POST_NOTIFICATIONS
            ) != PackageManager.PERMISSION_GRANTED
        ) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
                requestPermissions(arrayOf(Manifest.permission.POST_NOTIFICATIONS), 100)
            }
        }
        val notifs = listOf(createNotification(), createNotification(), createNotification())
        notifs.forEach {
            manager.notify(Random.nextInt(), it)
        }
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == 100 && grantResults.first() == PackageManager.PERMISSION_GRANTED) {
            val manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            val notifs = listOf(createNotification(), createNotification(), createNotification())
            notifs.forEach {
                manager.notify(Random.nextInt(), it)
            }
        }
    }

    private fun createNotificationChannel(manager: NotificationManager) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(
                CHANNEL_ID,
                "name",
                NotificationManager.IMPORTANCE_DEFAULT
            )
            manager.createNotificationChannel(channel)
        }
    }

    private fun createNotification(): Notification {
        return NotificationCompat.Builder(this, CHANNEL_ID)
            .setSmallIcon(R.drawable.ic_launcher_foreground)
            .setContentTitle("textTitle")
            .setContentText("textContent")
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .build()
    }
}