为扩展类添加属性

static void * MyObjectMyCustomPorpertyKey = (void *)@"MyObjectMyCustomPorpertyKey";

@implementation UIImageView (CanClick)

- (id)initWithFrame:(CGRect)frame {

self = [super initWithFrame:frame];

if (self) {

UITapGestureRecognizer *tapGes = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapGesPressed)];

[self addGestureRecognizer:tapGes];

}

return self;

}

- (NSString *)clickUrl {

return objc_getAssociatedObject(self,MyObjectMyCustomPorpertyKey);

}

- (void)setClickUrl:(NSString *)clickUrl {

objc_setAssociatedObject(self, MyObjectMyCustomPorpertyKey,clickUrl, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}

- (void)tapGesPressed {

[[SchemeHandler defaultHandler]handleUrl:self.clickUrl animated:YES];

}