如何在自定義類中使用presentViewController？

Question

我只是更新我的代碼，但alertWindow不會顯示出來。 我在Xcode中添加了斷點，它表明viewDelegate是零。 所有代表均爲零。 這是我的代碼：

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的方法，所以你需要一個視圖控制器的實例可以出示您的警報視圖。

通常這樣做的方式是讓視圖控制器啓動ClientReadThread實現AlertDelegate協議。 ClientReadThread沒有理由實現AlertDelegate本身。它會永遠是它自己的代表嗎？

另外你的代表應該標記爲weak否則你最終會得到一個保留週期。

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. 
    } 
} 

你的其他選擇是一個UIViewController實例的方式傳遞到ClientReadThread並用它來呈現警報視圖。儘管這不是我想要的方式。 ClientReadThread應該不需要知道它是如何處理警報的，應該委派給另一個類。