swift闭包和OC block类型的使用

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

//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

//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呐喊教程网站的支持！