之前看過一段swift，一直不知道OC中的block，即swift中的閉包是怎么實現的。今天就在網上搜索了一下，同時對比了一下OC中block類型的實現方法，然后寫了一個Demo測試一下。
使用說明：
swift版本
1.聲明類型 typealias hideShowView = (Int) -> Void
2.聲明屬性 var muFunc:hideShowView?
3.傳遞參數 func didSelectedToHideView(hideFunc:@escaping (Int)->Void) { muFunc = hideFunc }
4.監聽值的變化 func tapEvent() { muFunc!(0) }
5.使用 showView.didSelectedToHideView { (para) in NSLog("%d", para) }
6.Void 是返回值類型，Int是參數類型，hideShowView是閉包的類型名稱.第5項中的para是閉包的參數名，經測試，這個參數名在使用閉包的時候可以任意修改
OC版本
.h文件
//聲明一個block類型typedef void(^HideShowViewBlock)(int index); //聲明一個block屬性@property (nonatomic,copy) HideShowViewBlock hideViewBlock;//傳遞參數的方法 - (void)didHideShowViewWithBlock:(HideShowViewBlock)hideViewBlock;
.m文件
//實現傳遞參數的函數- (void)didHideShowViewWithBlock:(HideShowViewBlock)hideViewBlock{ self.hideViewBlock = hideViewBlock;}//監聽需要傳遞值的變化- (void)tapEvent{ self.hideViewBlock(0);}swift 閉包 Demo的代碼class ShowView: UIView{ typealias hideShowView = (Int) -> Void var muFunc:hideShowView? private var viewFram:CGRect? override init(frame:CGRect ) { super.init(frame: frame) self.viewFram = frame self.backgroundColor = UIColor.gray self.createUI() } func createUI() { var centerLabel = UILabel.init(frame: CGRect.init(x: 0, y: 0, width: (self.viewFram?.width)!, height: 20)) centerLabel.center = self.center centerLabel.text = "測試" centerLabel.textColor = UIColor.white centerLabel.textAlignment = NSTextAlignment.center centerLabel.font = UIFont.boldSystemFont(ofSize: 16.0) self.addSubview(centerLabel) let tap = UITapGestureRecognizer.init(target: self, action: #selector(ShowView.tapEvent)) tap.cancelsTouchesInView = false self.addGestureRecognizer(tap) } func tapEvent() { muFunc!(0) } func didSelectedToHideView(hideFunc:@escaping (Int)->Void) { muFunc = hideFunc } required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") }}class ViewController: UIViewController{ let WIDTH = UIScreen.main.bounds.size.width let HEIGHT = UIScreen.main.bounds.size.height override func viewDidLoad() { super.viewDidLoad() } @IBAction func selectedToDoSomething(_ sender: UIButton) { let showView = ShowView.init(frame: CGRect.init(x: 0, y: 0, width: WIDTH/2, height: WIDTH/2)) showView.center = self.view.center showView.didSelectedToHideView { (para) in NSLog("%d", para) } self.view.addSubview(showView) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. }}總結
以上所述是小編給大家介紹的swift閉包和OC block類型的使用，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對VEVB武林網網站的支持！
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