使用Xamarin.Forms和Azure推送通知：设备未注册

Question

I followed the following tutorial step by step: https://docs.microsoft.com/it-it/azure/notification-hubs/xamarin-notification-hubs-push-notifications-android-gcm

I started the Android app on a physical device with Android 8.0.0. Then also on 3 emulators (API 23, 25 and 27).

In the Azure control panel, the registered devices are always zero. As a result, the sending test is successful, but no notification arrives on the devices (" Message was successfully sent, but there were no matching targets ").

I skipped a few steps concerning the registration of devices?

* Code integration * ***[start code]

MainActivity.cs

namespace test021_push.Droid
{
    [Activity(Label = "test021_push", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
    {
        public const string TAG = "MainActivity";

        protected override void OnCreate(Bundle savedInstanceState)
        {
            TabLayoutResource = Resource.Layout.Tabbar;
            ToolbarResource = Resource.Layout.Toolbar;

            base.OnCreate(savedInstanceState);

            //push notification
            if (Intent.Extras != null)
            {
                foreach (var key in Intent.Extras.KeySet())
                {
                    if (key != null)
                    {
                        var value = Intent.Extras.GetString(key);
                        Log.Debug(TAG, "Key: {0} Value: {1}", key, value);
                    }
                }
            }

            global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
            LoadApplication(new App());
        }
    }
}

Constants.cs

namespace test021_push.Droid
{
    public static class Constants
    {
        public const string ListenConnectionString = "Endpoint=sb://namespacepodo.servicebus.windows.net/;SharedAccessKeyName=DefaultListenSharedAccessSignature;SharedAccessKey=lN8fZnQYlYQ/ELVrgnzUD16MBw9bOTH/Yxaw2LANA58=";
        public const string NotificationHubName = "notificationHubPodo";
    }
}

MyFirebaseIIDService.cs

namespace test021_push.Droid
{
    [Service]
    [IntentFilter(new[] { "com.google.firebase.INSTANCE_ID_EVENT" })]
    public class MyFirebaseIIDService : FirebaseInstanceIdService
    {
        const string TAG = "MyFirebaseIIDService";
        NotificationHub hub;

        public override void OnTokenRefresh()
        {
            var refreshedToken = FirebaseInstanceId.Instance.Token;
            Log.Debug(TAG, "FCM token: " + refreshedToken);
            SendRegistrationToServer(refreshedToken);
        }

        void SendRegistrationToServer(string token)
        {
            // Register with Notification Hubs
            hub = new NotificationHub(Constants.NotificationHubName, Constants.ListenConnectionString, this);

            var tags = new List<string>() { };
            var regID = hub.Register(token, tags.ToArray()).RegistrationId;

            Log.Debug(TAG, $"Successful registration of ID {regID}");
        }
    }
}

MyFirebaseMessagingService.cs

namespace test021_push.Droid
{
    [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 Notification.Builder(this)  //Notification.Builder è deprecato
            var notificationBuilder = new NotificationCompat.Builder(this)
                        .SetContentTitle("FCM Message")
                        .SetSmallIcon(Resource.Drawable.ic_launcher)
                        .SetContentText(messageBody)
                        .SetAutoCancel(true)
                        .SetContentIntent(pendingIntent);

            var notificationManager = NotificationManager.FromContext(this);

            notificationManager.Notify(0, notificationBuilder.Build());
        }
    }
}

***[end code]

Now notifications arrive only on a device (emulator Android API 25). In the other emulators (APIs 23 and 27) and in the physical device, nothing happens . Despite having done the exact same procedure on all 4 devices.

And on Azure I see 3 registered devices..

Thank you very much for your answers.

Answer 1

Have you checked in the firebase console if the devices are being registred?

Also check the log while starting the app. It is possible that registering at firebase fails. Just search the logs for "firebase". Also try adding a breakpoint in OnTokenRefresh()

If this fails, it could be that your google-services.json is wrong or has the wrong Build Action.

Edit: The Azure docs are outdated. Android 8.0 added the Notification channel feature. And you have to use it, otherwise the Notification will not be shown. This however fixes only displaying the notification. If the notification does not arrive in OnMessageReceived(RemoteMessage message) there is another bug.

I solved it like this in the SendNotification method

        var channelId = "testChannelId";
        var channelDescription = "Test Description";

        var builder = Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.O
            ? new Notification.Builder(Android.App.Application.Context, channelId)
            : new Notification.Builder(Android.App.Application.Context);

        var notification = builder
                    .SetContentTitle("Test")
                    .SetContentText(messageBody)
                    .SetSmallIcon(Resource.Drawable.ic_notification)
                    .SetAutoCancel(true)
                    .SetWhen(DateTime.Now.ToUnixMillisecondTime())
                    .SetShowWhen(true)
                    .Build();
        var notificationManager = NotificationManager.FromContext(Application.Context);

        if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.O)
        {
            var channel = new NotificationChannel(channelId,
                    channelDescription,
                    NotificationImportance.Default);
            notificationManager.CreateNotificationChannel(channel);
        }