swift给UIbutton添加闭包扩展，方便，简单实用

import UIKit

let cmButtonAssociatedkey = UnsafeRawPointer.init(bitPattern: "cmButtonAssociatedkey".hashValue)

extension UIButton {

    func addAction(for controlEvents: UIControlEvents,action:@escaping (UIButton)->()) {

        objc_setAssociatedObject(self, cmButtonAssociatedkey, action, .OBJC_ASSOCIATION_COPY_NONATOMIC)

        self.addTarget(self, action: #selector(cmButtonClick), for: controlEvents)

    }

    

    func addAction(_ action:@escaping (UIButton)->()) {

        objc_setAssociatedObject(self, cmButtonAssociatedkey, action, .OBJC_ASSOCIATION_COPY_NONATOMIC)

        self.addTarget(self, action: #selector(cmButtonClick), for: .touchUpInside)

    }

    

    func cmButtonClick() {

        if let action = objc_getAssociatedObject(self, cmButtonAssociatedkey) as? (UIButton)->() {

            action(self)

        }

    }

}