Push notifications not working in Xamarin.Android

Question

I have configured push notifications for a Xamarin.Android app using Azure Notification Hub and Firebase. I have followed this tutorial

When sending a test push notification from Azure Notification Hub I can see that my notification code is getting called so it seems like everything is configured. No errors occur, but no push notification is received either.

    [Service]
    [IntentFilter(new[] { "com.google.firebase.MESSAGING_EVENT" })]
    public class MyFirebaseMessagingService : FirebaseMessagingService
    {
        const string TAG = "MyFirebaseMsgService";
        public override void OnMessageReceived(RemoteMessage message)
        {
            Log.Debug(TAG, "From: " + message.From);
            if (message.GetNotification() != null)
            {
                //These is how most messages will be received
                Log.Debug(TAG, "Notification Message Body: " + message.GetNotification().Body);
                SendNotification(message.GetNotification().Body);
            }
            else
            {
                //Only used for debugging payloads sent from the Azure portal
                SendNotification(message.Data.Values.First());
            }
        }

        void SendNotification(string messageBody)
        {
            var intent = new Intent(this, typeof(MainActivity));
            intent.AddFlags(ActivityFlags.ClearTop);
            var pendingIntent = PendingIntent.GetActivity(this, 0, intent, PendingIntentFlags.OneShot);

            var notificationBuilder = new NotificationCompat.Builder(this)
                .SetContentTitle("FCM Message")
                .SetSmallIcon(Resource.Drawable.drivingalert)
                .SetContentText(messageBody)
                .SetAutoCancel(true)
                .SetContentIntent(pendingIntent);

            var notificationManager = NotificationManager.FromContext(this);
            notificationManager.Notify(0, notificationBuilder.Build()); // this should send the notification!!
        }
    }

I can step through the code and all appears to work without a problem but no push notification is received.

Answer 1

Call the following method in your MainActivity to set a notification channel:

void CreateNotificationChannel()
    {
        if (Build.VERSION.SdkInt < BuildVersionCodes.O)
        {
            // Notification channels are new in API 26 (and not a part of the
            // support library). There is no need to create a notification 
            // channel on older versions of Android.
            return;
        }

        var channel = new NotificationChannel(CHANNEL_ID, "FCM Notifications", NotificationImportance.Default)
                      {
                          Description = "Firebase Cloud Messages appear in this channel"
                      };

        var notificationManager = (NotificationManager) GetSystemService(NotificationService);
        notificationManager.CreateNotificationChannel(channel);
    }

If you check the Firebase Github they have updated this code but it doesn't seem to be available in their docs and also other push notification server docs have not updated it yet which is causing people to face this issue at a huge rate, Thanks for pointing this out I will raise this issue with Mircosoft!

Update

Also, check that you use Notification Compat classes for backward compatibility something like below:

 var intent = new Intent(this, typeof(MainActivity));
 intent.AddFlags(ActivityFlags.ClearTop);               
 var pendingIntent = PendingIntent.GetActivity(this, 0, intent, PendingIntentFlags.OneShot);

 NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
             .SetSmallIcon(Resource.Drawable.Icon)
             .SetContentTitle(messageTitle)
             .SetContentText(messageBody)
             .SetSound(Settings.System.DefaultNotificationUri)
             .SetVibrate(new long[] { 1000, 1000 })
             .SetLights(Color.AliceBlue, 3000, 3000)
             .SetAutoCancel(true)
             .SetOngoing(true)
             .SetContentIntent(pendingIntent);
            NotificationManagerCompat notificationManager = NotificationManagerCompat.From(this);
            notificationManager.Notify(0, notificationBuilder.Build());