如何关闭模态并同时发送数据并执行 segue

Question

我有一个聊天应用程序，想通过使用模态转场从我的ChatController 转到newMessageVC。在newMessageVC 中，我的所有联系人都显示在表格视图中。当点击一个联系人时，newMessaenter code heregeVC 应该关闭并且点击的联系人应该被发送到ChatController。此时，ChatController 应该执行 segue 以转到 ChatVC 以显示与单击用户的新聊天。我该怎么做？

我尝试了以下代码：

newMessageVC 正在关闭，函数showChatVC 被调用（它显示了打印语句），但随后出现了错误，尽管 segue 确实存在。从ChatController 到ChatVC 有一个名为showChatVC 的segue

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Receiver (<WeAreFriends.ChatController: 0x7fd760e22e80>) has no segue with identifier 'showChatVC''

class ChatController : UITableViewController {

    //MARK: - Outlets

    @IBOutlet weak var MessageTableView: UITableView!


    //MARK: - Properties

    var messages = [MessageModel]()

    //Mark: - Init View Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()

        configureNavigationBar()
    }


    //MARK: - Navigation Bar

    func configureNavigationBar() {
        navigationItem.title = "Messages"
         navigationController?.navigationBar.barTintColor = Defaults.hexStringToUIColor(hex: "#006D79")
        let textAttributes = [NSAttributedString.Key.foregroundColor: Defaults.hexStringToUIColor(hex: "#FFAA01")]
        navigationController?.navigationBar.titleTextAttributes = textAttributes
        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(handleNewMessage))
    }

    @objc func handleNewMessage(){
        performSegue(withIdentifier: "showNewMessage", sender: self)
    }

    //MARK: - Show ChatVC

    func showChatVC(forUser user: UserModel){
        print("Shooow, jihaaaaa")
        let messageController = MessageController()
        messageController.user = user
        performSegue(withIdentifier: "showChatVC", sender: self)

    }

    //MARK: - Prepare for segue

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "showNewMessage" {
            let destinationVC = segue.destination as! NewMessageController
            destinationVC.chatController = ChatController()
        }

    }

    //MARK: - Table Config

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return messages.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "MessagesTableViewCell", for: indexPath) as! MessagesTableViewCell

        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        print("did select row")
    }
}

newMessageVC：

class NewMessageController: UITableViewController {

    //MARK: - Outlets

    @IBOutlet var NewMessageTableView: UITableView!

    //MARK: - Var/let

    var users = [UserModel]()

    var chatController : ChatController?

    //Mark: - Init View Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()

        configureNavigationBar()
        fetchUser()
    }

    //MARK: - User laden

    func fetchUser(){
        UserApi.shared.observeUsersButCurrentUser { (user) in
            self.users.append(user)
            self.NewMessageTableView.reloadData()
        }
    }

    //MARK: - Navigation Bar

    func configureNavigationBar() {
        navigationItem.title = "New Message"
        navigationController?.navigationBar.barTintColor = Defaults.hexStringToUIColor(hex: "#006D79")
        let textAttributes = [NSAttributedString.Key.foregroundColor: Defaults.hexStringToUIColor(hex: "#FFAA01")]
        navigationController?.navigationBar.titleTextAttributes = textAttributes
    }

    //MARK: - Tableview Config
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return users.count
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "NewMessageTableViewCell", for: indexPath) as! NewMessageTableViewCell

        cell.user = users[indexPath.row]

        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

        self.dismiss(animated: true) {

            let user = self.users[indexPath.row]
            self.chatController!.showChatController(forUser: user)
        }
    }

}

我做错了什么？

Answer 1

替换

destinationVC.chatController = ChatController()

与

destinationVC.chatController = self

因为ChatController() 是一个新的不同实例，没有附加故事板布局，所以没有segues 因此崩溃

---

func showChatVC(forUser user: UserModel){ 
    performSegue(withIdentifier: "showChatVC", sender:user) 
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "showNewMessage" {
        let destinationVC = segue.destination as! NewMessageController
        destinationVC.chatController = ChatController()
    }
    else if segue.identifier == "showChatVC" {
        let destinationVC = segue.destination as! ChatVC
        destinationVC.user = sender as! UserModel
    }
}

也做

weak var chatController : ChatController?

为了不引起保留循环