Swift3.0 - 黑魔法swizzle

  extension UIButton{
   class func swip(){
    // 创建一个结构体,写个静态变量
    struct T{
        static let x:Bool = {
            let cls: AnyClass = UIButton.self
            // 创建消息对象
            let originalSelector = #selector(UIButton.sendAction(_:to:for:))
            let swizzleSelector = #selector(UIButton.swizzle_sendAction(action:to:forEvent:))
            // 创建方法
            let ori_method = class_getInstanceMethod(cls, originalSelector)
            let swi_method = class_getInstanceMethod(cls, swizzleSelector)
            
            print(ori_method)
            print(swi_method)
            // 交换两个方法的实现部分
            method_exchangeImplementations(ori_method,swi_method)
            print("执行了............")
            return false
        }()
    }
    // 这里必须执行一下,不然没法创建静态变量
    T.x
}

// 定义要交换的函数
public  func swizzle_sendAction(action: Selector,
                                to: AnyClass!,
                                forEvent: UIEvent!){
    // 定义一个累加器
    struct button_tap_count{
        static var count = 0
    }
    button_tap_count.count += 1
    print(button_tap_count.count)
    // 看似好像调用了自己构成死循环,但是 我们其实已经将两个方法名的实现进行了调换 所以 其实我们调用的是 方法sendAction:to:forEvent 的实现 这样就可以在不破环原先方法结构的基础上进行交换实现
    swizzle_sendAction(action: action, to: to, forEvent: forEvent)
}
}

class ViewController: UIViewController {
     @IBOutlet weak var button: UIButton!
    override func viewDidLoad() {
        super.viewDidLoad()
         // 执行一次交换方法
         UIButton.swip()
         button.addTarget(self, action: #selector(tap(button:)), for: .touchUpInside)
    }

    func tap(button:UIButton){
        print("你好")
    }
}