Runtime实现UIButton+Block

#import 
typedef void(^ButtonBlock)(UIButton* btn);

@interface UIButton (Block)

- (void)addAction:(ButtonBlock)block;
- (void)addAction:(ButtonBlock)block forControlEvents:(UIControlEvents)controlEvents;

@end

#import "UIButton+Block.h"
#import 

@implementation UIButton (Block)
static char ActionTag;

- (void)addAction:(ButtonBlock)block
{
    objc_setAssociatedObject(self, &ActionTag, block, OBJC_ASSOCIATION_COPY_NONATOMIC);
    [self addTarget:self action:@selector(action:) forControlEvents:UIControlEventTouchUpInside];
}

- (void)addAction:(ButtonBlock)block forControlEvents:(UIControlEvents)controlEvents
{
    objc_setAssociatedObject(self, &ActionTag, block, OBJC_ASSOCIATION_COPY_NONATOMIC);
    [self addTarget:self action:@selector(action:) forControlEvents:controlEvents];
}

- (void)action:(id)sender
{
    ButtonBlock blockAction = (ButtonBlock)objc_getAssociatedObject(self, &ActionTag);
    if (blockAction)
    {
        blockAction(self);
    }
}

@end

只能用于一种evet下，如果为两种evet使用会出现覆盖，执行后关联的block