Block扩展UIButton写法记录

1.使用runtime机制中的objc_setAssociatedObject和objc_getAssociatedObject方法

@interface UIButton (LXAdd)

  - (void)addTargetEvents:(UIControlEvents)Events block:(void (^)(id sender))block;

@end

@implementation UIButton (LXAdd)

- (void)invoke:(id)sender {
   void (^block)(id sender) = objc_getAssociatedObject(self, &block_key);
    block(sender);
}

- (void)addTargetEvents:(UIControlEvents)Events block:(void (^)(id sender))block{
    if(!Events) return;
    objc_setAssociatedObject(self, &block_key, block, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    [self addTarget:self action:@selector(invoke:) forControlEvents:Events];
}

@end