c# - Notifications are not delivering xamarin android

Question

When the notification is recieved following code is handling the message:

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

    var notificationBuilder = new Notification.Builder(this)
            .SetContentTitle("GCM Message")
            .SetContentText(message)
            .SetAutoCancel(true)
            .SetContentIntent(pendingIntent);

     var notificationManager = (NotificationManager)GetSystemService(Context.NotificationService);
     notificationManager.Notify(0, notificationBuilder.Build());
}

But nothing shows. I'm debugging it it that would make any difference? When I go to settings on the app on the device, "Show notifications" is checked.

Comment 1:

using (var notificationManager = NotificationManager.FromContext(ApplicationContext))
{
    var title = "Title";
    var channelName = "TestChannel"
    if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
    {
        NotificationChannel channel = null;
        if (channel == null)
        {
            channel = new NotificationChannel(channelName, channelName, NotificationImportance.Low)
            {
                LockscreenVisibility = NotificationVisibility.Public
            };
            channel.SetShowBadge(true);
            notificationManager.CreateNotificationChannel(channel);
        }
        channel.Dispose();
    }
    var bitMap = BitmapFactory.DecodeResource(Resources, Resource.Drawable.notification_template_icon_bg);
    var notificationBuilder = new NotificationCompat.Builder(ApplicationContext)
                                                            .SetContentTitle(title)
                                                            .SetContentText(message)
                                                            .SetLargeIcon(bitMap)
                                                            .SetShowWhen(false)
                                                            .SetChannelId(channelName);

    var notification = notificationBuilder.Build();
    notificationManager.Notify(0, notification);
}

Runnig that code, no errors but nothing shows up.

Thanks for the help!

Answer 1

With the newer Android APIs, they now require a notification channel (NotificationChannel) to be used. You can do fairly easily by using NotificationCompat from the Android support library and only creating the channel if you are on Oreo or later.

NotificationCompat w/ Channel Example:

using (var notificationManager = NotificationManager.FromContext(ApplicationContext))
{
    var channelName = GetText(Resource.String.notificationChannelNormal);
    if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
    {
        NotificationChannel channel = null;
        #if !DEBUG
        channel = notificationManager.GetNotificationChannel(channelName);
        #endif
        if (channel == null || resetChannel)
        {
            channel = new NotificationChannel(channelName, channelName, NotificationImportance.Low)
            {
                LockscreenVisibility = NotificationVisibility.Public
            };
            channel.SetShowBadge(true);
            notificationManager.CreateNotificationChannel(channel);
        }
        channel.Dispose();
    }
    Bitmap bitMap = BitmapFactory.DecodeResource(Resources, Resource.Drawable.ic_launcher);
    var notificationBuilder = new NotificationCompat.Builder(ApplicationContext)
                                                    .SetContentTitle(title)
                                                    .SetContentText(message)
                                                    .SetSmallIcon(Resource.Drawable.ic_stat_notification_network_locked)
                                                    .SetLargeIcon(bitMap)
                                                    .SetShowWhen(false)
                                                    .SetChannelId(channelName)
                                                    .SetContentIntent(pendingIntent);
    return notificationBuilder.Build();
}