typealias sendValueClosure = (swipeGesture: UISwipeGestureRecognizer) -> Void</span> class SwipeGesture:NSObject { //声明一个闭包 var myClosure: sendValueClosure? //下面的方法需要传入上个界面的someFunctionThatAClosure函数指针 func initWithClosure(closuer: sendValueClosure?) { //讲函数指针赋值给myClosure闭包,该闭包中覆盖了someFunctionThatTakesAClosure函数中的局部变量等引用 self.myClosure = closuer } func setSwipeGesture(view:UIView){ //设置手势 let swipeRight = UISwipeGestureRecognizer(target: self,action: "respondToSwipeGesture:") swipeRight.direction = UISwipeGestureRecognizerDirection.Right view.addGestureRecognizer(swipeRight) let swipeLeft = UISwipeGestureRecognizer(target: self,action: "respondToSwipeGesture:") swipeLeft.direction = UISwipeGestureRecognizerDirection.Left view.addGestureRecognizer(swipeLeft) let swipeUp = UISwipeGestureRecognizer(target: self,action: "respondToSwipeGesture:") swipeUp.direction = UISwipeGestureRecognizerDirection.Up view.addGestureRecognizer(swipeUp) let swipeDown = UISwipeGestureRecognizer(target: self,action: "respondToSwipeGesture:") swipeDown.direction = UISwipeGestureRecognizerDirection.Down view.addGestureRecognizer(swipeDown) } //事件 func respondToSwipeGesture(gesture: UIGestureRecognizer){ if let swipeGesture = gesture as? UISwipeGestureRecognizer { if let closure = self.myClosure { closure(swipeGesture: swipeGesture) } } } }这个类功能就是封装UISwipeGestureRecognizer,添加上下左右4种滑动手势及相应的时间,这些都不重要,重要的是:
//声明一个闭包 var myClosure: sendValueClosure? //下面的方法需要传入上个界面的someFunctionThatAClosure函数指针 func initWithClosure(closuer: sendValueClosure?) { //讲函数指针赋值给myClosure闭包,该闭包中覆盖了someFunctionThatTakesAClosure函数中的局部变量等引用 self.myClosure = closuer }
声明的闭包myClosure在类的最上面那句代码:
typealias sendValueClosure = (swipeGesture: UISwipeGestureRecognizer) -> VoidinitWithClosure(closure: sendValueClosure)这个函数是被我们UIView源文件调用的。
下面respondToSwipeGesture(gesture:UIGestureRecognizer)事件触发的时候,里面的
if let closure = self.myClosure { closure(swipeGesture: swipeGesture) }
是把 UISwipeGestureRecognizer 当做参数返回给闭包。
//实例化类 let mySwipeGesture = SwipeGesture() // 给 UIView 添加手势 mySwipeGesture.setSwipeGesture( yourView) //调用闭包监听事件 mySwipeGesture.initWithClosure { (swipeGesture) -> Void in switch swipeGesture.direction { case UISwipeGestureRecognizerDirection.Right: print("Swiped right") case UISwipeGestureRecognizerDirection.Left: print("Swiped left") case UISwipeGestureRecognizerDirection.Up: print("Swiped up") case UISwipeGestureRecognizerDirection.Down: print("Swiped down") default: break } }是的,就是这么简单。。手势不是目的,封装不是目的,目的是学会用闭包实现数据监听及传送数据。 原文链接:https://www.f2er.com/swift/324456.html