IOS setOnclick点击事件分析

[_btn1 setOnclick:^{
  NSLog(@"click btn1");
}];

btn.setOnClick {
  print("click btn")
}

  #import <UIKit/UIKit.h>

  @interface UIButton(click)
  @property (nonatomic, strong) void (^clickBlock) (void);
  - (void) setOnclick : (void (^)(void))block;
  - (void) clickBtn : (UIButton*) sender;
  - (void) setTarget : action:(SEL)action;
  @end
  

  #import "UIButton+click.h"
  #import <objc/runtime.h>
  
  @implementation UIButton(click)
  
  static void *clickKey = &clickKey;
  - (void)setClickBlock:(void (^)(void))clickBlock{
    objc_setAssociatedObject(self, & clickKey, clickBlock, OBJC_ASSOCIATION_COPY);
  }
  
  - (void (^)(void))clickBlock{
    return objc_getAssociatedObject(self, &clickKey);
  }
  
  -(void)setOnclick:(void (^)(void))block{
    self.clickBlock = block;
    [self addTarget:self action:@selector(clickBtn:) forControlEvents:UIControlEventTouchUpInside];
  }
  
  - (void) clickBtn : (UIButton*) sender{
    self.clickBlock();
  }
  
  @end

  class UIClick : Any{
    var click : () -> Void = {return}
  }
  
  extension UIButton : Property{
    var saveClick : UIClick{
      get{
        return get0()
      }
      set{
        return set0(newValue)
      }
    }
    
    func setOnClick(click : @escaping () -> Void) {
      self.saveClick = UIClick()
      self.saveClick.click = click
      self.addTarget(self, action: #selector(btnClick), for: .touchUpInside)
    }
    
    @objc func btnClick(){
      self.saveClick.click()
    }
  }

  func setOnClickView(click : @escaping () -> Void) {
    self.isUserInteractionEnabled = true
    self.saveClickView = UIClick()
    self.saveClickView.click = click
    let tap = UITapGestureRecognizer(target: self, action: #selector(btnClickView))
    tap.numberOfTapsRequired = 1
    self.addGestureRecognizer(tap)
  }