Swift 在UIButton扩展中添加 block 点击事件

直接看代码，代码中有详细注释

extension UIButton {
      // 定义关联的Key
      private struct UIButtonKeys {
         static var clickKey = "UIButton+Extension+ActionKey"
      }
      
      func addActionWithBlock(_ closure: @escaping (_ sender:UIButton)->()) {
          //把闭包作为一个值 先保存起来
         objc_setAssociatedObject(self, &UIButtonKeys.clickKey, closure, objc_AssociationPolicy.OBJC_ASSOCIATION_COPY)
          //给按钮添加传统的点击事件，调用写好的方法
         self.addTarget(self, action: #selector(my_ActionForTapGesture), for: .touchUpInside)
      }
      @objc private func my_ActionForTapGesture() {
         //获取闭包值
         let obj = objc_getAssociatedObject(self, &UIButtonKeys.clickKey)
         if let action = obj as? (_ sender:UIButton)->() {
             //调用闭包
             action(self)
         }
      }
}

使用测试：

lazy var codeBtn: UIButton = {
        let btn = UIButton(frame: CGRect.init(x: 100, y: 100, width: 200, height: 50))
        btn.backgroundColor = .white
        btn.setTitle("验证码1", for: .normal)
        btn.tag = 10081
        btn.setTitleColor(.lightGray, for: .normal)
        btn.titleLabel?.font = UIFont.systemFont(ofSize: 14)
        btn.addActionWithBlock { btn in
            printLog("btn == \(String(describing: btn.currentTitle))")
            printLog("btn.tag == \(btn.tag)")
        }
        return btn
    }()
    lazy var codeBtn1: UIButton = {
        let btn = UIButton(frame: CGRect.init(x: 100, y: 200, width: 200, height: 50))
        btn.backgroundColor = .white
        btn.setTitle("验证码2", for: .normal)
        btn.tag = 10082
        btn.setTitleColor(.lightGray, for: .normal)
        btn.titleLabel?.font = UIFont.systemFont(ofSize: 14)
        btn.addActionWithBlock { btn in
            printLog("btn == \(String(describing: btn.currentTitle))")
            printLog("btn.tag == \(btn.tag)")
        }
        return btn
    }()

//点击按钮 打印结果
2022-03-17 11:31:06.052000 TestFristController.swift -> codeBtn [第26行] btn == Optional("验证码1")
2022-03-17 11:31:06.055000 TestFristController.swift -> codeBtn [第27行] btn.tag == 10081
2022-03-17 11:31:07.603000 TestFristController.swift -> codeBtn1 [第39行] btn == Optional("验证码2")
2022-03-17 11:31:07.604000 TestFristController.swift -> codeBtn1 [第40行] btn.tag == 10082

传统点击事件addTarget依然可以用
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