推送通知在 Xamarin.Android 中不起作用

Question

我使用 Azure Notification Hub 和 Firebase 为 Xamarin.Android 应用配置了推送通知。我关注了这个tutorial

当从 Azure 通知中心 发送测试推送通知时，我可以看到我的通知代码被调用，所以看起来一切都已配置。没有错误发生，但也没有收到推送通知。

    [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!!
        }
    }

我可以单步执行代码，一切似乎都可以正常工作，但没有收到推送通知。

Answer 1

在您的 MainActivity 中调用以下方法设置通知通道：

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);
    }

如果您查看 Firebase Github，他们已更新此代码，但在他们的文档中似乎不可用，而且其他推送通知服务器文档尚未更新，这导致人们在巨大的费率，感谢您指出这一点，我将向 Mircosoft 提出这个问题！

更新

此外，请检查您是否使用 Notification Compat 类来实现向后兼容性，如下所示：

 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());