ChatViewController.swift

var agoraRtm: AgoraRtmKit?
var friendID: String?


var handle: AuthStateDidChangeListenerHandle?
var currentUser: User?


var messageList: [String] = []


override func viewDidLoad() {
   super.viewDidLoad()


   agoraRtm = AgoraRtmKit(appId: "YOUR_AGORA_APP_ID", delegate: self)


   tableView.register(UITableViewCell.self, forCellReuseIdentifier: "chatCell")
}


override func viewWillAppear(_ animated: Bool) {
   handle = Auth.auth().addStateDidChangeListener { (auth, user) in
       self.currentUser = user
       if let username = user?.displayName, let friendName = self.friendID {
           self.navigationItem.title = friendName
           self.agoraRtm?.login(byToken: nil, user: username, completion: { (error) in
               if error != .ok {
                   print("error logging in")
               }
           })
       } else {
           //Handle logout
       }
   }
}


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