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使用代理和闭包(closure)反向传值

使用代理和闭包(closure)反向传值

作者: 彧哥哥 | 来源:发表于2017-07-27 15:30 被阅读0次
    1.png
    import UIKit
    
    class FirstViewController: UIViewController, SecondViewControllerDelegate {
    
        @IBOutlet weak var showTextLabel: UILabel!
        @IBOutlet weak var showDelegateTextLabel: UILabel!
        
        override func viewDidLoad() {
            super.viewDidLoad()
    
            // Do any additional setup after loading the view.
        }
        
        //点击按钮跳转到SecondViewController
        @IBAction func tapGoSecondViewController(sender: UIButton) {
            //从storyboard上加载SecondViewController
            let secondVC = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle()).instantiateViewControllerWithIdentifier("secondViewController") as! SecondViewController
            //实现回调,获取回调回来的值 (闭包)
            secondVC.backClosure = {
                (backStr: String) -> Void in
                self.showTextLabel.text = backStr
            }
            secondVC.delegate = self
            //跳转到SecondViewController
            self.navigationController?.pushViewController(secondVC, animated: true)
        }
        //MARK: - SecondViewControllerDelegate(代理)
        func fetchBackString(str: String) {
            self.showDelegateTextLabel.text = str
        }
        
        override func didReceiveMemoryWarning() {
            super.didReceiveMemoryWarning()
            // Dispose of any resources that can be recreated.
        }
    }
    

    SecondViewController的代码

    2.png
    import UIKit
     
    //定义闭包类型(特定的函数类型函数类型)
    typealias InputClosureType = (String) -> Void
     
    protocol SecondViewControllerDelegate: NSObjectProtocol{
        func fetchBackString(str: String)
    }
     
    class SecondViewController: UIViewController {
         
        @IBOutlet weak var inputTextField: UITextField!
        //接收上个页面传过来的闭包块
        var backClosure: InputClosureType?
        weak var delegate: SecondViewControllerDelegate?
         
        override func viewDidLoad() {
            super.viewDidLoad()
     
            // Do any additional setup after loading the view.
        }
     
        @IBAction func tapBackButton(sender: UIButton) {
            if self.backClosure != nil {
                if let tempString = self.inputTextField.text {
                    self.backClosure!(tempString)
                }
            }
            self.navigationController?.popViewControllerAnimated(true)
        }
         
        @IBAction func delegateBackMethod(sender: UIButton) {
            if self.delegate != nil {
                if let tempString = self.inputTextField.text {
                    delegate!.fetchBackString("代理返回数据:\(tempString)")
                }
            }
            self.navigationController?.popViewControllerAnimated(true)
        }
         
        override func didReceiveMemoryWarning() {
            super.didReceiveMemoryWarning()
            // Dispose of any resources that can be recreated.
        }
    }
    

    效果视图:


    3.png 4.png

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