注意点：如果不是 NSObject或者其子类，那么需要将 替换方法前 + dynamic 可动态派发

extension UIButton {

classfunc Mrshan_swizzleSendAction() {

struct xxx_swizzleToken {

staticvar onceToken : dispatch_once_t =0

}

//设定这个方法只是执行一次，在第一个uibutton初始化的时候执行这个方法，嘻嘻

dispatch_once(&xxx_swizzleToken.onceToken) {

let cls:AnyClass! = UIButton.self

let originalSelector =Selector("sendAction:to:forEvent:")

let swizzledSelector =Selector("Mrshan_sendAction:to:forEvent:")

let originalMethod =class_getInstanceMethod(cls,originalSelector)

let swizzledMethod =class_getInstanceMethod(cls,swizzledSelector)

method_exchangeImplementations(originalMethod,swizzledMethod)

//在这里进行方法实现的替换,下一个页面中的两个方法的互换

let cls1 =twoViewController.self

let originSelect1 =Selector("one")

let swizzleSelect1 =Selector("two")

let originMethod1 =class_getInstanceMethod(cls1,originSelect1)

let swizzleMethod1 =class_getInstanceMethod(cls1,swizzleSelect1)

method_exchangeImplementations(originMethod1,swizzleMethod1)

}

}

/**

这个是被调换的方法的实现

- parameter action: <#action description#>

- parameter to: <#to description#>

- parameter forEvent: <#forEvent description#>

*/

publicfunc Mrshan_sendAction(action: Selector,

to: AnyObject!,

forEvent: UIEvent!)

{

//计数器+=1

xxx_buttonTapCounter.count +=1

print(xxx_buttonTapCounter.count)

//这里并不是调用的自己，因为在执行这个方法的时候，Mrshan_sendAction 和 sendAction 的实现已经调换了，所以执行的是原来的button的点击事件

Mrshan_sendAction(action,to: to,forEvent: forEvent)

}

/**

重写构造方法，并且确认构造者是uibutton

- returns: <#return value description#>

*/

overridepublic classfunc initialize() {

//别用断言。。老实一点用IF

ifself != UIButton.self {

return

}

UIButton.Mrshan_swizzleSendAction()

}

}

/**

* button的点击计数器

*/

struct xxx_buttonTapCounter {

staticvar count: Int =0

}