ios - Firebase Messaging应该在首次启动应用程序时未建立连接

问题

首次启动应用程序时，或者在删除并重新安装后，Messaging.messaging().shouldEstablishDirectChannel不会建立套接字连接。如果我关闭了该应用程序，然后重新打开它，则建立了套接字连接。

重现步骤:

1)将此代码放在AppDelegate中:FirebaseApp.configure()Messaging.messaging().delegate = selfMessaging.messaging().shouldEstablishDirectChannel = true
2)将这段代码放在之后的任何地方，以检查是否建立了连接:Messaging.messaging().isDirectChannelEstablished这总是返回false。

3)监听连接状态的变化，并观察该通知从不触发。NotificationCenter.default.addObserver(self, selector: #selector(fcmConnectionStateChange), name: NSNotification.Name.MessagingConnectionStateChanged, object: nil)
简而言之，这就是问题所在。如果我只是杀死该应用程序，然后重新启动它，那么一切都会按预期进行。建立套接字连接，并触发MessagingConnectionStateChanged通知。

为什么Messaging.messaging().shouldEstablishDirectChannel在我的初始应用启动时没有连接？

相关代码

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        window = UIWindow(frame: UIScreen.main.bounds)
        window!.rootViewController = RootViewController.shared
        window!.makeKeyAndVisible()
        setUpFirebase()
        setUpPushNotificationsForApplication(application)
        RootViewController.shared.goToLoginVC()

        return true
    }

    // MARK: - Firebase

    func setUpFirebase() {
        NotificationCenter.default.addObserver(self, selector:
            #selector(fcmConnectionStateChange), name:
            NSNotification.Name.MessagingConnectionStateChanged, object: nil)
        FirebaseApp.configure()
        Messaging.messaging().delegate = self
        Messaging.messaging().shouldEstablishDirectChannel = true
    }

    // MARK: - Firebase Notifications

    func fcmConnectionStateChange() {
       // This is never called on app's first launch!!!
        print(Messaging.messaging().isDirectChannelEstablished)
    }

环境

Xcode版本:8.3.3

Firebase 4.1.0

FirebaseAnalytics 4.0.3

FirebaseCore 4.0.5

FirebaseInstanceID 2.0.1

FirebaseMessaging 2.0.1

Firebase产品:消息传递

最佳答案

在拥有 token 之前尝试进行FCM连接可能会失败。

我修改了您的代码，请尝试此操作。

func setUpFirebase() {
    NotificationCenter.default.addObserver(self, selector:
        #selector(self.tokenRefreshNotification), name:
        NSNotification.Name.InstanceIDTokenRefresh, object: nil)
    NotificationCenter.default.addObserver(self, selector:
        #selector(self.fcmConnectionStateChange), name:
        NSNotification.Name.MessagingConnectionStateChanged, object: nil)
    FirebaseApp.configure()
    Messaging.messaging().delegate = self
}

func tokenRefreshNotification(_ notification: Notification) {
    if let refreshedToken = InstanceID.instanceID().token() {
        print("InstanceID token: \(refreshedToken)")
    }

    // Connect to FCM since connection may have failed when attempted before having a token.
    connectToFcm()
}

func connectToFcm() {
    // Won't connect since there is no token
    guard InstanceID.instanceID().token() != nil else {
        return;
    }
    Messaging.messaging().shouldEstablishDirectChannel = true
}

func fcmConnectionStateChange() {
    if Messaging.messaging().isDirectChannelEstablished {
        print("Connected to FCM.")
    } else {
        print("Disconnected from FCM.")
    }
}

更新:
在使用NotificationCenter之前，请添加它。

    if #available(iOS 10, *) {
        print("iOS 10 up")
        let center = UNUserNotificationCenter.current()
        center.requestAuthorization(options: [.alert, .badge, .sound]) { (granted, error) in
            guard error == nil else {
                print("regist fail = \(String(describing: error))")
                return
            }
            if granted {
                print("allow regist")
            } else {
                //Handle user denying permissions..
                print("deny regist")
            }
        }
    } else {
        print("iOS 9 down")
        let pushNotificationSettings = UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
        application.registerUserNotificationSettings( pushNotificationSettings )
    }
    application.registerForRemoteNotifications()