AgoraVideoViewController.swift

func joinChannel() {
    localVideoView.isHidden = false

    if let name = userName {
        getAgoraEngine().joinChannel(byUserAccount: name, token: tempToken, channelId: channelName) { [weak self] (sid, uid, elapsed) in
            self?.userID = uid
        }
    } else {
        getAgoraEngine().joinChannel(byToken: tempToken, channelId: channelName, info: nil, uid: userID) { [weak self] (sid, uid, elapsed) in
            self?.userID = uid
        }
    }
}