关联对象

-(UIImageView *)btnImageView

{

// return objc_getAssociatedObject(self, @selector(isClicked));

return objc_getAssociatedObject(self, &kbtnImageView);

}

//set

static char kbtnImageView;

-(void)setBtnImageView:(UIImageView *)btnImageView

{

//如果是指针类型

return objc_setAssociatedObject(self, &kbtnImageView, btnImageView, OBJC_ASSOCIATION_RETAIN);

//1 源对象self

//2 关键字 唯一静态变量key isClicked

//3 关联的对象

//4 关键策略 OBJC_ASSOCIATION_RETAIN_NONATOMIC

//objc_setAssociatedObject(self, @selector(isClicked), @(isClicked), OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}