之前看过一段swift，一直不知道OC中的block，即swift中的闭包是怎么实现的。今天就在网上搜索了一下，同时对比了一下OC中block类型的实现方法，然后写了一个Demo测试一下。
使用说明：
swift版本
1.声明类型 typealias hideShowView = (Int) -> Void
2.声明属性 var muFunc:hideShowView?
3.传递参数 func didSelectedToHideView(hideFunc:@escaping (Int)->Void) { muFunc = hideFunc }
4.监听值的变化 func tapEvent() { muFunc!(0) }
5.使用 showView.didSelectedToHideView { (para) in NSLog("%d", para) }
6.Void 是返回值类型，Int是参数类型，hideShowView是闭包的类型名称.第5项中的para是闭包的参数名，经测试，这个参数名在使用闭包的时候可以任意修改
OC版本
.h文件
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//声明一个block类型typedef void(^HideShowViewBlock)(int index); //声明一个block属性@property (nonatomic,copy) HideShowViewBlock hideViewBlock;//传递参数的方法 - (void)didHideShowViewWithBlock:(HideShowViewBlock)hideViewBlock; |
.m文件
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//实现传递参数的函数- (void)didHideShowViewWithBlock:(HideShowViewBlock)hideViewBlock{ self.hideViewBlock = hideViewBlock;}//监听需要传递值的变化- (void)tapEvent{ self.hideViewBlock(0);}swift 闭包 Demo的代码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 = "测试" 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. }} |
总结
以上所述是小编给大家介绍的swift闭包和OC block类型的使用，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！
原文链接：http://www.jianshu.com/p/5ef55ff57f7a?utm_source=tuicool&utm_medium=referral
