swift - 如何在自定义类中使用presentViewController？

Question

我刚刚更新了我的代码，但alertWindow不会显示。我在 Xcode 中添加断点，它显示 viewDelegate 为零。所有委托(delegate)均为零。这是我的代码:

class LoginViewController:UIViewController,AlertDelegate
{
override func viewDidLoad() {
    super.viewDidLoad()

    let BackGroundImage:UIImageView = UIImageView(frame: CGRectMake(0, 0, self.view.frame.width , self.view.frame.height))

    let image: UIImage = UIImage(named: "backgroundLogin.jpg")!

    BackGroundImage.image = image
    self.view.addSubview(BackGroundImage)
    //self.view.backgroundColor = UIColor(patternImage: UIImage(named: "backgroundLogin.jpg")!)

    username.text = "User name"
    password.text = "Password"
    usernameWarning.text = ""
    passwordWarning.text = ""

    self.view.bringSubviewToFront(username)
    self.view.bringSubviewToFront(password)
    self.view.bringSubviewToFront(usernameText)
    self.view.bringSubviewToFront(passwordText)
    self.view.bringSubviewToFront(LoginButton)
    self.view.bringSubviewToFront(RegisterButton)

    self.view.bringSubviewToFront(usernameWarning)
    self.view.bringSubviewToFront(passwordWarning)


}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    switch segue.identifier
    {


    case .Some("RegisterSegue"):
        let registerViewController = segue.destinationViewController as! RegisterViewController

        if let temp_register_username = usernameText!.text
        {
            registerViewController.register_name = temp_register_username
            if let temp_register_pass = passwordText!.text
            {
                registerViewController.register_password = temp_register_pass
            }
        }
    case .Some("loginSegue"):
        let loginViewController = segue.destinationViewController as! FunctionsViewController
        loginViewController.client = client



    default:
        super.prepareForSegue(segue, sender: sender)



    }
}


override func shouldPerformSegueWithIdentifier(identifier: String, sender: AnyObject?) -> Bool {
    if identifier == "loginSegue"
    {
        if usernameText.text != ""
        {
            if passwordText.text != ""
            {


                let encrypt = encryptMsg(send: passwordText.text!)

                let encrypt_pass = encrypt.encryptSendMsg()

                let sendMsg = AppConfig.AddHead("login", body: usernameText.text!+"|"+encrypt_pass)
                let (_,_) = client.connect(timeout: 1)
                let (success,_) = client.send(str: sendMsg)
                if success
                {
                    let data = client.read(1024*10)
                    if let d = data
                    {
                        if let str = String(bytes: d, encoding: NSUTF8StringEncoding)
                        {
                            if str[0...2] == AppConfig.TransmissionAgreementConfiguration["successLogin"]
                            {
                                AppConfig.StoreUserID(str)

                                let defaults = NSUserDefaults()

                                defaults.setObject(usernameText.text!, forKey: "userName")

                                let acceptThread = AcceptThread()
                                acceptThread.start()

                                return true
                            }
                            else if str[0...2] == AppConfig.TransmissionAgreementConfiguration["errLoginUsernameNotExist"]
                            {
                                usernameWarning.text = "User name doesn't exist"
                                usernameWarning.reloadInputViews()

                                passwordWarning.text = ""
                                passwordWarning.reloadInputViews()
                                return false

                            }
                            else if str[0...2] == AppConfig.TransmissionAgreementConfiguration["errLoginUsernameAlreadyOnline"]
                            {
                                usernameWarning.text = "User account already be online"
                                usernameWarning.reloadInputViews()

                                passwordWarning.text = ""
                                passwordWarning.reloadInputViews()
                                return false
                            }
                            else if str[0...2] == AppConfig.TransmissionAgreementConfiguration["errLoginPassword"]
                            {
                                usernameWarning.text = ""
                                usernameWarning.reloadInputViews()

                                passwordWarning.text = "Password Incorrect"
                                passwordWarning.reloadInputViews()
                                return false
                            }
                        }
                    }
                }

                return false

            }
            else
            {
                usernameWarning.text = ""
                usernameWarning.reloadInputViews()

                passwordWarning.text = "password cannot be empty"
                passwordWarning.reloadInputViews()
                return false
            }

        }
        else
        {
            usernameWarning.text = "username cannot be empty"
            usernameWarning.reloadInputViews()
            return false
        }
    }
    else
    {
        return true
    }

}

func presentWindow(title:String,msg:String)
{

    let alertController = UIAlertController(title: "\(title):", message: "\(msg)", preferredStyle: UIAlertControllerStyle.Alert)
    alertController.addTextFieldWithConfigurationHandler{
        (textField: UITextField!) -> Void in
        textField.placeholder = "Message"
    }

    let cancelAction = UIAlertAction(title: "Ignore", style: UIAlertActionStyle.Cancel, handler: nil)

    let okAction = UIAlertAction(title: "Reply", style: UIAlertActionStyle.Default,
        handler: {
            action in
            let reply_msg = alertController.textFields!.first! as UITextField
            print("I replies \(reply_msg)")

    })
    alertController.addAction(cancelAction)
    alertController.addAction(okAction)
    self.presentViewController(alertController, animated: true, completion: nil)

}
@IBAction func logoutUnwindSegue(segue: UIStoryboardSegue) {
    // Intentionally left blank
}

var client:TCPClient = TCPClient(addr:"localhost",port:8889)


var AppConfig=TransmissionAgreement(first:"test")
@IBOutlet weak var usernameWarning: UILabel!

@IBOutlet weak var passwordWarning: UILabel!

@IBOutlet weak var username: UILabel!
@IBOutlet weak var password: UILabel!

@IBOutlet weak var usernameText: UITextField!
@IBOutlet weak var passwordText: UITextField!

@IBOutlet weak var LoginButton: UIButton!

@IBOutlet weak var RegisterButton: UIButton!
}

class AcceptThread: NSThread {
override func main() {
    let server:TCPServer = TCPServer(addr:"127.0.0.1",port: 7000)

    let (success,_) = server.listen()
    if success
    {

        while !cancelled
        {
            if let my_client = server.accept()
            {

                let clientReadThread = ClientReadThread(client: my_client)
                clientReadThread.start()
                clientThreads.append(clientReadThread)
            }
        }

        for clientThread in clientThreads {
            clientThread.cancel()
        }
    }
}

var clientThreads = Array<ClientReadThread>()
var AppConfig=TransmissionAgreement(first:"test")
}

@objc protocol AlertDelegate: class {
func presentWindow(title:String,msg:String)
}

@objc protocol ClientReadThreadDelegate: class {
func clientReadThread(clientReadThread: ClientReadThread, didReceiveMessage message: String)

}


class ClientReadThread:NSThread{
init(client: TCPClient) {
    self.client = client

     super.init()
}




override func main() {
    while !cancelled, let readValue = client.read(1024*10) {
        if let message = String(bytes: readValue, encoding: NSUTF8StringEncoding) {

            let head = message[0...2]
         //   print("head is \(head)")


            if head! == AppConfig.TransmissionAgreementConfiguration["add"]
            {
                let defaults = NSUserDefaults()
                let myname = defaults.stringForKey("userName")


                    //store data
                    let context = CoreDataService.sharedCoreDataService.mainQueueContext
                    let friend = NSEntityDescription.insertNewObjectForNamedEntity(Friends.self, inManagedObjectContext: context)
                    friend.name = message.substringFromIndex(3)

                    try! context.save()

                    let sendMsg = AppConfig.AddClientHead("agreeAdd", body:myname)

                    let (_,_) = client.send(str:sendMsg)
                    dispatch_async(dispatch_get_main_queue(), { () -> Void in
                        self.delegate?.clientReadThread(self, didReceiveMessage: message)
                    })


            }
            else if head! == AppConfig.TransmissionAgreementConfiguration["chat"]
            {
                let search = message.substringFromIndex(3)
                 let resultController = try? catFriend.sharedCatFriendsService.catBlack(search)
                 try! resultController!.performFetch()

                 let flag = resultController?.sections?.count

                if flag <= 1//friend
                {

                    dispatch_async(dispatch_get_main_queue(), { () -> Void in

                        let client_info = message.split("|")
                        let client_name = client_info[1]

                        //self.alertDelegate?.presentWindow(client_name, msg: client_info[2])
                        self.viewDelegate?.presentWindow(client_name, msg: client_info[2])

                    })


                }
                else//black, not show the meg
                {
                    //do nothing
                }

            }

        }
    }
}

var AppConfig=TransmissionAgreement(first:"test")
let client: TCPClient
var viewDelegate:LoginViewController?
var delegate: ClientReadThreadDelegate?
var alertDelegate: AlertDelegate?
private var resultController: NSFetchedResultsController?
}

Answer 1

presentViewContoller 是 UIViewController 上的一种方法，因此您需要一个 View Controller 的实例才能呈现您的警报 View 。

通常完成此操作的方法是让您启动 ClientReadThread 的 View Controller 实现 AlertDelegate 协议(protocol)。 ClientReadThread 没有理由实现 AlertDelegate 本身。它会是它自己的委托(delegate)吗？

此外，您的委托(delegate)应该标记为weak，否则您将最终陷入保留周期。

class MyViewController : UIViewController, AlertDelegate {
     private var clientReadThread: ClientReadThread?

     override viewDidLoad() {
          super.viewDidLoad();
          clientReadThread = ClientReadThread(someTcpClient)
          clientReadThread.viewDelegate = self
     }

     func presentWindow(title:String,msg:String) {
         // Your code goes here.
     }
}

您的另一个选择是将 UIViewController 的实例传递到 ClientReadThread 中，并使用它来呈现警报 View 。虽然那不是我愿意走的路。 ClientReadThread 不需要知道它的警报是如何处理的，这应该委托(delegate)给另一个类。