AgoraVideoViewController.swift

var handle: AuthStateDidChangeListenerHandle?
var userName: String?
var channelName = "default"

override func viewDidAppear(_ animated: Bool) {
    handle = Auth.auth().addStateDidChangeListener { (auth, user) in
        if user == nil {
            self.navigationController?.popToRootViewController(animated: true)
        } else {
            self.userName = user?.displayName
        }
    }
    joinChannel()
}

override func viewWillDisappear(_ animated: Bool) {
    leaveChannel()
    if let handle = handle {
        Auth.auth().removeStateDidChangeListener(handle)
    }
}

func setUserName(name: String?) {
    userName = name
    if let name = name {
        getAgoraEngine().registerLocalUserAccount(name, appId: appID)
    }
}

func setChannelName(channel: String) {
    channelName = channel
}