Notifications

Why notifications need channels

Since Android 8.0, every notification must belong to a channel — a category like “Messages” or “Promotions”. Users can then mute or customise each channel individually. You create channels once, usually at app start.

Create a channel

val channel = NotificationChannel(
    "messages", "Messages", NotificationManager.IMPORTANCE_HIGH
).apply { description = "Chat messages" }

val manager = getSystemService(NotificationManager::class.java)
manager.createNotificationChannel(channel)

Build and show a notification

val notification = NotificationCompat.Builder(this, "messages")
    .setSmallIcon(R.drawable.ic_message)
    .setContentTitle("New message")
    .setContentText("Anand sent you a message")
    .setPriority(NotificationCompat.PRIORITY_HIGH)
    .setAutoCancel(true)             // dismiss when tapped
    .build()

NotificationManagerCompat.from(this).notify(1, notification)

Opening a screen when tapped

val intent = Intent(this, ChatActivity::class.java)
val pending = PendingIntent.getActivity(
    this, 0, intent, PendingIntent.FLAG_IMMUTABLE
)
// .setContentIntent(pending) on the builder

The Android 13+ permission

On Android 13 and newer you must also request the POST_NOTIFICATIONS runtime permission before notifications appear.

Common mistakes

• Forgetting to create the channel (nothing shows on Android 8+).
• Not requesting POST_NOTIFICATIONS on Android 13+.
• Spamming notifications — users will turn them off.

Summary: Create a channel, build with NotificationCompat, attach a PendingIntent to open a screen, and request the notifications permission on Android 13+.