startForeground Notification does not show Title or Content

Question

I'm starting a foreground service which uses a HandlerThread to do some long running tasks.

It works fine, however, the notification does not show my title or content (It says "xxx is running " Tap for more information or to stop the app"). I'm targeting Android 10 for now

The service is started from my main activity

Log.w(TAG, "startServiceCalled")
Intent(this, MyService::class.java).also { intent ->
    startForegroundService(intent)
}

In the onCreate callback of the Service I'm putting the service in the foreground like this

val pendingIntent: PendingIntent =
    Intent(this, MainActivity::class.java).let { notificationIntent ->
    PendingIntent.getActivity(this, 0, notificationIntent, 0)
}

val notification: Notification = NotificationCompat.Builder(applicationContext, MainActivity.RECORDING_NOTIFICATION_CHANNEL.id)
    .setOngoing(true)
    .setContentTitle("My Custom App")
    .setContentText("MyService Ready")
    .setContentIntent(pendingIntent)
    .build()

startForeground(NOTIFICATIION_ID, notification, ServiceInfo.FOREGROUND_SERVICE_TYPE_MANIFEST);

BTW: I'm also using Flutter so my main activity extends FlutterActivity

EDIT: The notification channel is created like this

val RECORDING_NOTIFICATION_CHANNEL = NotificationChannel("com.example.notification", "Service notifications", NotificationManager.IMPORTANCE_DEFAULT).apply {
    description = "Provides information about the service"
}
val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
notificationManager.createNotificationChannel(RECORDING_NOTIFICATION_CHANNEL);

Solution

I found the issue:

You need to set a valid small icon. Otherwise the notification display will fail silently during startForeground.

val notification: Notification = NotificationCompat.Builder(applicationContext, MainActivity.RECORDING_NOTIFICATION_CHANNEL.id)
        .setOngoing(true)
        .setSmallIcon(R.mipmap.ic_launcher)
        .setContentTitle("MyService")
        .setContentText("Recording Service Ready")
        .setContentIntent(pendingIntent)
        .build()

I discovered this when trying to display the notification manually using NotificationManager.notify.