如何創建委派到一個視圖控制器上的另一個視圖控制器

Question

在這裏，我有兩個視圖控制器，並在第二視圖控制器按鈕點擊我希望在第一視圖控制器更改標籤的名稱，這樣的按鈕，點擊更改標籤名稱我怎麼能做這個？？

第一個視圖控制器在這裏我想更改用戶名的標籤文本

class MenuViewController1: UIViewController,UITableViewDataSource, UITableViewDelegate{ 

    /** 
    * Array to display menu options 
    */ 
    @IBOutlet var tblMenuOptions : UITableView! 

    /** 
    * Transparent button to hide menu 
    */ 
    @IBOutlet var btnCloseMenuOverlay : UIButton! 

    /** 
    * Array containing menu options 
    */ 
    var arrayMenuOptions = [Dictionary<String,String>]() 

    /** 
    * Menu button which was tapped to display the menu 
    */ 
    var btnMenu : UIButton! 

    /** 
    * Delegate of the MenuVC 
    */ 
    var delegate : SlideMenuDelegate? 

    // var delegateP: Profile? 

    @IBOutlet weak var userProfilePhoto: UIImageView! 

    @IBOutlet weak var userName: UILabel! 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     tblMenuOptions.tableFooterView = UIView() 
     // Do any additional setup after loading the view. 


     //let name = userName.text 
     self.delegateP?.name_changed(name: userName.text!) 

     } 

    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 

    override func viewWillAppear(_ animated: Bool) { 
     super.viewWillAppear(animated) 
     updateArrayMenuOptions() 
    } 

    func updateArrayMenuOptions(){ 
     arrayMenuOptions.append(["title":"Home", "icon":"HomeIcon"]) 
     arrayMenuOptions.append(["title":"LogIn", "icon":"LogIn"]) 
     arrayMenuOptions.append(["title":"House Owner","icon":"House Owner"]) 
     arrayMenuOptions.append(["title":"ShortTerm", "icon":"ShortTerm"]) 
     arrayMenuOptions.append(["title":"LongTerm","icon":"LongTerm"]) 

     tblMenuOptions.reloadData() 
    } 

    @IBAction func onCloseMenuClick(_ button:UIButton!){ 
     btnMenu.tag = 0 

     if (self.delegate != nil) { 
      var index = Int32(button.tag) 
      if(button == self.btnCloseMenuOverlay){ 
       index = -1 
      } 
      delegate?.slideMenuItemSelectedAtIndex(index) 
     } 

     UIView.animate(withDuration: 0.3, animations: {() -> Void in 
      self.view.frame = CGRect(x: -UIScreen.main.bounds.size.width, y: 0, width: UIScreen.main.bounds.size.width,height: UIScreen.main.bounds.size.height) 
      self.view.layoutIfNeeded() 
      self.view.backgroundColor = UIColor.clear 
     }, completion: { (finished) -> Void in 
      self.view.removeFromSuperview() 
      self.removeFromParentViewController() 
     }) 
    } 

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { 
     let cell : UITableViewCell = tableView.dequeueReusableCell(withIdentifier: "cellMenu")! 
     cell.selectionStyle = UITableViewCellSelectionStyle.none 
     cell.layoutMargins = UIEdgeInsets.zero 
     cell.preservesSuperviewLayoutMargins = false 

     cell.backgroundColor = UIColor.clear 


     let lblTitle : UILabel = cell.contentView.viewWithTag(101) as! UILabel 
     let imgIcon : UIImageView = cell.contentView.viewWithTag(100) as! UIImageView 

     imgIcon.image = UIImage(named: arrayMenuOptions[indexPath.row]["icon"]!) 
     lblTitle.text = arrayMenuOptions[indexPath.row]["title"]! 

     return cell 
    } 

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { 
     let btn = UIButton(type: UIButtonType.custom) 
     btn.tag = indexPath.row 
     self.onCloseMenuClick(btn) 
    } 

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 
     return arrayMenuOptions.count 
    } 

    func numberOfSections(in tableView: UITableView) -> Int { 
     return 1; 
    } 
} 

第二個視圖控制器從那裏上登錄按鈕的點擊要改變第一個視圖控制器的標籤名稱

class LogInViewController: UIViewController , FBSDKLoginButtonDelegate , GIDSignInUIDelegate{ 
    @IBOutlet weak var loginButton: UIButton! 
    @IBOutlet weak var EnterEmail: UITextField! 
    @IBOutlet weak var EnterPassword: UITextField!  

    // Login in button 

    @IBAction func loginButtton(_ sender: UIButton) { 

     let email = EnterEmail.text?.lowercased() 
     let finalEmail = email?.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines) 
     let password = EnterPassword.text 

     // var name: String! 
     // menuView = self.storyboard?.instantiateViewController(withIdentifier: "MenuViewController1") as! MenuViewController1 

     // Register user in firebase with validations 
     Auth.auth().createUser(withEmail: email!, password: password!) { (user, error) in 

      if (error == nil && (finalEmail != "") && self.isValidEmail(testStr: finalEmail!)) && (password != " " && self.isPasswordValid(password!)) { 
       self.displayMyAlertMessage(userMessage:"You are successfully registered ")     
      } else { 
       self.displayMyAlertMessage(userMessage:"Registration Failed.. Please Try Again !")      
      } 
     }; 
     // self.navigationController?.pushViewController(MenuViewController1, animated: true) 
    } 
} 

Answer 1

我們假設MenuViewController將被通知LoginViewController已完成登錄。的方式是：

首先，在LoginViewController創建協議與LoginViewController，並聲明委託：

protocol LoginViewControllerDelegate:NSObjectProtocol { 
    func LoginDidFinish() 
} 

class LoginViewController: UIViewController{ 

    weak var delegate:LoginViewControllerDelegate? 
    //...... 
} 

二，當登錄結束時，調用委託方法：

Auth.auth().createUser(withEmail: email!, password: password!) { (user, error) in 
    if (error == nil && (finalEmail != "") && self.isValidEmail(testStr: finalEmail!)) && (password != " " && self.isPasswordValid(password!)){ 
     self.displayMyAlertMessage(userMessage:"You are successfully registered ") 
     self.delegate?.LoginDidFinish() //Key point 
    }else{ 
     self.displayMyAlertMessage(userMessage:"Registration Failed.. Please Try Again !") 
    } 
}; 

三，在MenuViewController，分配self是LoginViewController的代表創建LoginViewController時：

let loginViewController = LoginViewController() 
loginViewController.delegate = self 

最後，實現委託方法在MenuViewController，它會被調用時，登錄完成：

//MARK: - LoginViewControllerDelegate 
func LoginDidFinish() { 
    print("Login did finish") 
    //And change your label's text here. 
}