Have you had experience working with the NotificationChannel mechanism for sending notifications?

NotificationChannel is a mechanism introduced in Android 8.0 (API 26) for managing notifications. It allows grouping notifications into channels with different importance levels, sounds, and visual effects. When sending a notification, you need to specify the channel; otherwise, the notification will not be shown.

Example of creating a channel:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    val channel = NotificationChannel(
        "channel_id",
        "Main Channel",
        NotificationManager.IMPORTANCE_DEFAULT
    ).apply {
        description = "Channel description"
    }
    val notificationManager: NotificationManager =
        context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
    notificationManager.createNotificationChannel(channel)
}

After that, when creating a notification, specify this channel:

val notification = NotificationCompat.Builder(context, "channel_id")
    .setContentTitle("Title")
    .setContentText("Notification text")
    .setSmallIcon(R.drawable.ic_notification)
    .build()

notificationManager.notify(notificationId, notification)