如何创建委派到一个视图控制器上的另一个视图控制器

Question

在这里，我有两个视图控制器，并在第二视图控制器按钮点击我希望在第一视图控制器更改标签的名称，这样的按钮，点击更改标签名称我怎么能做这个？？

第一个视图控制器在这里我想更改用户名的标签文本

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; 
    } 
} 

第二个视图控制器从那里上登录按钮的点击要改变第一个视图控制器的标签名称

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

我们假设MenuViewController将被通知LoginViewController已完成登录。的方式是：

首先，在LoginViewController创建协议与LoginViewController，并声明委托：

protocol LoginViewControllerDelegate:NSObjectProtocol { 
    func LoginDidFinish() 
} 

class LoginViewController: UIViewController{ 

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

二，当登录结束时，调用委托方法：

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的代表创建LoginViewController时：

let loginViewController = LoginViewController() 
loginViewController.delegate = self 

最后，实现委托方法在MenuViewController，它会被调用时，登录完成：

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