关联对象UIButton -- block

#import <UIKit/UIKit.h>
#import <objc/runtime.h>

NS_ASSUME_NONNULL_BEGIN

// 声明一个button点击事件的回调block
typedef void(^ButtonClickCallBack)(UIButton *button);

@interface UIButton (Handle)

// 为UIButton增加的回调方法
- (void)handleClickCallBack:(ButtonClickCallBack)callBack;

@end

NS_ASSUME_NONNULL_END
///====================================================
#import "UIButton+Handle.h"

// 声明一个静态的索引key，用于获取被关联对象的值
static char *buttonClickKey;

@implementation UIButton (Handle)

- (void)handleClickCallBack:(ButtonClickCallBack)callBack {
    // 将button的实例与回调的block通过索引key进行关联：
    objc_setAssociatedObject(self, &buttonClickKey, callBack, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    
    // 设置button执行的方法
    [self addTarget:self action:@selector(buttonClicked) forControlEvents:UIControlEventTouchUpInside];
}

- (void)buttonClicked {
    // 通过静态的索引key，获取被关联对象（这里就是回调的block）
    ButtonClickCallBack callBack = objc_getAssociatedObject(self, &buttonClickKey);
    
    if (callBack) {
        callBack(self);
    }
}

@end

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@end
///==========================================
#import "ViewController.h"
#import "UIButton+Handle.h"

@interface ViewController ()

@property (nonatomic, strong) UIButton *testButton;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.view.backgroundColor = [UIColor whiteColor];
    self.title = @"Test3ViewController";
    
    UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];
    button1.frame = CGRectMake(50, 150, 250, 100);
    button1.backgroundColor = [[UIColor blueColor] colorWithAlphaComponent:0.1];
    [button1 setTitle:@"UIButton+Handle" forState:UIControlStateNormal];
    
    self.testButton = button1;
    [self.view addSubview:self.testButton];
    [self.testButton handleClickCallBack:^(UIButton *button) {
        NSLog(@"block --- click UIButton+Handle");
    }];
}

@end