Swift 统计项目中所有按钮的点击次数

class Swizzle: NSObject {
    override class func load() {
        UIButton.xxx_swizzleSendAction()
    }
}

extension UIButton {
    class func xxx_swizzleSendAction() {
        struct xxx_swizzleToken {
            static var onceToken : dispatch_once_t = 0
        }
        dispatch_once(&xxx_swizzleToken.onceToken, { () -> Void in
            let cls : AnyClass! = UIButton.self
            let originalSelector = Selector("sendAction:to:forEvent:")
            let swizzledSelector = Selector("xxx_sendAction:to:forEvent:")
            let originalMethod = class_getInstanceMethod(cls, originalSelector)
            let swizzledMethod = class_getInstanceMethod(cls, swizzledSelector)
            method_exchangeImplementations(originalMethod, swizzledMethod)

        })
    }
    public  func xxx_sendAction(action : Selector, to : AnyObject!, forEvent : UIEvent!) {
        struct xxx_buttonTapCount {
            static var count : Int = 0
        }
        xxx_buttonTapCount.count += 1
        println(xxx_buttonTapCount.count)
        xxx_sendAction(action, to: to, forEvent: forEvent)
    }

}