Question

我正在我的Xamarin Forms应用中为我的Android项目设置推送通知。我一直在关注在线文档（https://developer.xamarin.com/guides/xamarin-forms/cloud-services/push-notifications/azure/）以使其正常运行，但我遇到了一些问题

1 - 当我从Azure Notification Hub发送测试时，通知无法到达。 2 - 在Register方法中经过一段时间后，应用程序在调试期间崩溃。

我认为问题是由注册引起的，我不认为注册正在运行，因此应用超时导致崩溃，Azure通知中心也成功发送消息但没有设备捡起来（可能是因为它没有注册）

首先，这是我到目前为止所做的事情。

我在console.firebase.google.com中设置了一个项目，并按照说明记录了发件人ID和服务器密钥。我已经将项目ID命名为myapp-android-app。
我已将documtation中的所有代码添加到我的Android项目中。
我已向Azure中的通知中心添加了GCM通知服务，并为其提供了我的Firebase应用注册中记录的服务器密钥。
我已将我的Google帐户添加到我的Andoird模拟器

以下是我的Android项目的源代码。

MainActivity.cs

using System;
using Android.App;
using Android.Content.PM;
using Android.OS;
using Gcm.Client;

namespace MyApp.Droid
{
    [Activity(Label = "@string/app_name", Theme = "@style/MyTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
    {
        //public static MainActivity CurrentActivity { get; private set; }

        // Create a new instance field for this activity.
        static MainActivity instance = null;

        // Return the current activity instance.
        public static MainActivity CurrentActivity
        {
            get
            {
                return instance;
            }
        }
        protected override void OnCreate(Bundle bundle)
        {
            instance = this;
            base.OnCreate(bundle);

            global::Xamarin.Forms.Forms.Init(this, bundle);
            Microsoft.WindowsAzure.MobileServices.CurrentPlatform.Init();
            LoadApplication(new App());

            try
            {
                // Check to ensure everything's setup right
                GcmClient.CheckDevice(this);
                GcmClient.CheckManifest(this);

                // Register for push notifications
                System.Diagnostics.Debug.WriteLine("Registering...");
                GcmClient.Register(this, PushHandlerBroadcastReceiver.SENDER_IDS);
            }
            catch (Java.Net.MalformedURLException)
            {
                CreateAndShowDialog("There was an error creating the client. Verify the URL.", "Error");
            }
            catch (Exception e)
            {
                CreateAndShowDialog(e.Message, "Error");
            }

            TabLayoutResource = Resource.Layout.Tabbar;
            ToolbarResource = Resource.Layout.Toolbar;

        }
        void CreateAndShowDialog(String message, String title)
        {
            AlertDialog.Builder builder = new AlertDialog.Builder(this);

            builder.SetMessage(message);
            builder.SetTitle(title);
            builder.Create().Show();
        }
    }
}

GcmService.cs

using Android.App;
using Android.Content;
using Android.Media;
using Android.Support.V4.App;
using Android.Util;
using Gcm.Client;
using Microsoft.WindowsAzure.MobileServices;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;

[assembly: Permission(Name = "@PACKAGE_NAME@.permission.C2D_MESSAGE")]
[assembly: UsesPermission(Name = "@PACKAGE_NAME@.permission.C2D_MESSAGE")]
[assembly: UsesPermission(Name = "com.google.android.c2dm.permission.RECEIVE")]
[assembly: UsesPermission(Name = "android.permission.INTERNET")]
[assembly: UsesPermission(Name = "android.permission.WAKE_LOCK")]
//GET_ACCOUNTS is only needed for android versions 4.0.3 and below
[assembly: UsesPermission(Name = "android.permission.GET_ACCOUNTS")]
namespace MyApp.Droid
{
    [BroadcastReceiver(Permission = Gcm.Client.Constants.PERMISSION_GCM_INTENTS)]
    [IntentFilter(new string[] { Gcm.Client.Constants.INTENT_FROM_GCM_MESSAGE }, Categories = new string[] { "@PACKAGE_NAME@" })]
    [IntentFilter(new string[] { Gcm.Client.Constants.INTENT_FROM_GCM_REGISTRATION_CALLBACK }, Categories = new string[] { "@PACKAGE_NAME@" })]
    [IntentFilter(new string[] { Gcm.Client.Constants.INTENT_FROM_GCM_LIBRARY_RETRY }, Categories = new string[] { "@PACKAGE_NAME@" })]
    public class PushHandlerBroadcastReceiver : GcmBroadcastReceiverBase<GcmService>
    {
        public static string[] SENDER_IDS = new string[] { "xxxxxxxxxx" };
    }

    [Service]
    public class GcmService : GcmServiceBase
    {
        public static string RegistrationToken { get; private set; }

        public GcmService()
            : base(PushHandlerBroadcastReceiver.SENDER_IDS) { }

        protected override void OnRegistered(Context context, string registrationToken)
        {
            Log.Verbose("PushHandlerBroadcastReceiver", "GCM Registered: " + registrationToken);
            RegistrationToken = registrationToken;

            var push = AzureService.DefaultManager.CurrentClient.GetPush();
            MainActivity.CurrentActivity.RunOnUiThread(() => Register(push, null));
        }

        protected override void OnUnRegistered(Context context, string registrationToken)
        {
            Log.Error("PushHandlerBroadcastReceiver", "Unregistered RegisterationToken: " + registrationToken);
        }

        protected override void OnError(Context context, string errorId)
        {
            Log.Error("PushHandlerBroadcastReceiver", "GCM Error: " + errorId);
        }

        public async void Register(Microsoft.WindowsAzure.MobileServices.Push push, IEnumerable<string> tags)
        {
            try
            {
                const string templateBodyGCM = "{\"data\":{\"message\":\"$(messageParam)\"}}";

                JObject templates = new JObject();
                templates["genericMessage"] = new JObject
                {
                    {"body", templateBodyGCM}
                };

                await push.RegisterAsync(RegistrationToken, templates);
                Log.Info("Push Installation Id", push.InstallationId.ToString());
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex.Message + ex.StackTrace);
                Debugger.Break();
            }
        }

        protected override void OnMessage(Context context, Intent intent)
        {
            Log.Info("PushHandlerBroadcastReceiver", "GCM Message Received!");

            var msg = new StringBuilder();

            if (intent != null && intent.Extras != null)
            {
                foreach (var key in intent.Extras.KeySet())
                    msg.AppendLine(key + "=" + intent.Extras.Get(key).ToString());
            }

            // Retrieve the message
            var prefs = GetSharedPreferences(context.PackageName, FileCreationMode.Private);
            var edit = prefs.Edit();
            edit.PutString("last_msg", msg.ToString());
            edit.Commit();

            string message = intent.Extras.GetString("message");
            if (!string.IsNullOrEmpty(message))
            {
                CreateNotification("New todo item!", "Todo item: " + message);
            }

            string msg2 = intent.Extras.GetString("msg");
            if (!string.IsNullOrEmpty(msg2))
            {
                CreateNotification("New hub message!", msg2);
                return;
            }

            CreateNotification("Unknown message details", msg.ToString());
        }

        void CreateNotification(string title, string desc)
        {
            // Create notification
            var notificationManager = GetSystemService(Context.NotificationService) as NotificationManager;

            // Create an intent to show the UI
            var uiIntent = new Intent(this, typeof(MainActivity));

            // Create the notification
            // we use the pending intent, passing our ui intent over which will get called
            // when the notification is tapped.
            NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
            var notification = builder.SetContentIntent(PendingIntent.GetActivity(this, 0, uiIntent, 0))
                    .SetSmallIcon(Android.Resource.Drawable.SymActionEmail)
                    .SetTicker(title)
                    .SetContentTitle(title)
                    .SetContentText(desc)
                    .SetSound(RingtoneManager.GetDefaultUri(RingtoneType.Notification)) // set the sound
                    .SetAutoCancel(true).Build(); // remove the notification once the user touches it

            // Show the notification
            notificationManager.Notify(1, notification);
        }
    }
}

我使用我在Firebase控制台应用中记录的public static string[] SENDER_IDS = new string[] { "xxxxxxxx" }; ID替换了Sender中的字符串。

当我通过Android模拟器运行应用程序时，我在大约3分钟后收到以下错误。

GcmService.cs 中的错误：

Exception: System.Threading.Tasks.TaskCanceledException: A task was canceled.

见于第71行：

await push.RegisterAsync(RegisteToken, templates);

有谁知道我做错了什么？我是否认为它没有正确注册？

Answer 1

我能够在Xamarin.Forms（包括Android和iOS）中集成Firebase云消息传递，遵循官方Xamarin指南，该解释得到了很好的解释：

https://developer.xamarin.com/guides/android/application_fundamentals/notifications/remote-notifications-with-fcm/

查看您的代码，在我看来，您使用旧的Gcm服务（已弃用）而不是新的Fcm。你应该有一个 google-services.json 文件和一个 FirebaseMessagingService 类

然后......

请注意

截至目前，Xamarin Forms在开发时不能很好地处理应用程序的部署，进行脏重新安装，似乎使以前获得的 Notification Token 无效调用Fcm库的方法时，有时会引发 IllegalStateException 。

这是一个已知的错误，可以通过清理解决方案来解决   重新发起

我是否正确设置了Android推送通知？

1 个答案: