Swift 使用代理和閉包(closure)反向傳值,swiftclosure

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Swift 使用代理和閉包(closure)反向傳值,swiftclosure
FirstViewController的代碼


import UIKitclass 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. } //點擊按鈕跳轉到SecondViewController @IBAction func tapGoSecondViewController(sender: UIButton) { //從storyboard上載入SecondViewController let secondVC = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle()).instantiateViewControllerWithIdentifier("secondViewController") as! SecondViewController //實現回調,擷取回調回來的值 (閉包) secondVC.backClosure = { (backStr: String) -> Void in self.showTextLabel.text = backStr } secondVC.delegate = self //跳轉到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的代碼
import UIKit//定義閉包類型(特定的函數類型函數類型)typealias InputClosureType = (String) -> Voidprotocol SecondViewControllerDelegate: NSObjectProtocol{    func fetchBackString(str: String)}class SecondViewController: UIViewController {        @IBOutlet weak var inputTextField: UITextField!    //接收上個頁面傳過來的閉包塊    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("代理返回資料:\(tempString)")            }        }        self.navigationController?.popViewControllerAnimated(true)    }        override func didReceiveMemoryWarning() {        super.didReceiveMemoryWarning()        // Dispose of any resources that can be recreated.    }}
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