FCM - Android Xamarin未注册错误发送消息后，重新调试应用程序

由于此问题仅发生在调试应用程序时从Visual Studio运行应用程序时(不在部署到PlayStore的版本中)，我所做的是暂时解决这个问题，我创建了以下服务:

    [Service]
    public class FCMRegistrationService : IntentService
    {
        private const string Tag = "FCMRegistrationService";
        static object locker = new object();
        protected override void OnHandleIntent(Intent intent)
        {
            try
            {
                lock (locker)
                {
                    var instanceId = FirebaseInstanceId.Instance;
                    var token = instanceId.Token;
                    if (string.IsNullOrEmpty(token))
                        return;
#if DEBUG
                    instanceId.DeleteToken(token, "");
                    instanceId.DeleteInstanceId();
#endif

                }
            }
            catch (Exception e)
            {
                Log.Debug(Tag, e.Message);
            }
        }
    }

然后在我的启动活动(每当应用程序打开时加载的活动)中执行以下操作:

protected override void OnCreate(Bundle savedInstanceState)
{
            base.OnCreate(savedInstanceState);

#if DEBUG
            if (!IsMyServiceRunning("FCMRegistrationService"))
            {
                var intent = new Intent(this, typeof(FCMRegistrationService));
                StartService(intent);
            }
            // For debug mode only - will accept the HTTPS certificate of Test/Dev server, as the HTTPS certificate is invalid /not trusted
            ServicePointManager.ServerCertificateValidationCallback += (o, certificate, chain, errors) => true;
#endif
}

这将注销您现有的FCMToken并刷新令牌，因此将调用OnTokenRefresh方法，然后您将不得不编写一些逻辑来更新服务器上的FCMToken。

[Service, IntentFilter(new[] { "com.google.firebase.INSTANCE_ID_EVENT" })]
public class FCMInstanceIdService : FirebaseInstanceIdService
{
   // private string LogTag = "FCMInstanceIdService";
    public override void OnTokenRefresh()
    {
        var fcmDeviceId = FirebaseInstanceId.Instance.Token;
        // Settings (is Shared Preferences) - I save the FCMToken Id in shared preferences 
       // if FCMTokenId is not the same as old Token then update on the server
        if (Settings.FcmTokenId != fcmDeviceId)
        {
            var oldFcmId = Settings.FcmTokenId;
            var validationContainer = new ValidationContainer();
            // HERE UPDATE THE TOKEN ON THE SERVER
            TBApp.Current._usersProvider.UpdateFcmTokenOnServer(oldFcmId, fcmDeviceId, validationContainer);
            Settings.FcmTokenId = fcmDeviceId;
        }
        base.OnTokenRefresh();
    }
}

我手动尝试这样初始化

 var options = new FirebaseOptions.Builder()
             .SetApplicationId("YOURAPPID")
             .SetApiKey("YOURAPIKEY")
             //.SetDatabaseUrl(Keys.Firebase.Database_Url) //i'M not using it
             .SetGcmSenderId("YOURSENDERID")
    //.SetStorageBucket(Keys.Firebase.StorageBucket)//i'M not using it
    .Build();
        try
        {   //try to initilize firebase app to get token
            FirebaseApp.InitializeApp(Forms.Context, options);//initializeto get token
        }
        catch
        {   //if app already initialized it will throw exception, so get the previous active token and send to your server-database etc
            var instanceId = FirebaseInstanceId.Instance;
            var token = instanceId.Token;
            Service.MyFirebaseMessagingService.RegisterForAndroid(token); //this method sends the token to my server app, you have to write your own
        }

所以当用户打开应用程序时，我试图重新初始化Firebase应用程序。如果它已经初始化，它会抛出一个异常:)我在那里取令牌，所以它给了我活跃的注册令牌。如果应用程序没有初始化，一切都将顺利工作，所以你的OnTokenRefresh方法将按预期触发。