相关疑难解决方法(0)

我想子类UIButton添加一些我需要的属性(不是方法...只有属性).

这是我的子类的代码:

//.h-----------------------
@interface MyButton : UIButton{
    MyPropertyType *property;
}

@property (nonatomic,retain) MyPropertyType *property;
@end

//.m--------------------------
@implementation MyButton
@synthesize property;

@end

在这里我如何使用该类:

MyButton *btn = ((MytButton *)[MyButton buttonWithType:UIButtonTypeRoundedRect]);
btn.property = SomeDataForTheProperty;

从哪里获得此错误:

 -[UIRoundedRectButton setProperty:]: unrecognized selector sent to instance 0x593e920

因此,从ButtonWithType我获得一个UIRoundedRectButton,(Mybutton *)不能施展它...我需要做什么来获得一个MyButton对象？是-init唯一的解决方案？

谢谢!

因为我们知道,我们可以添加使用类别和运行方法,如在Objective-C的变量 objc_setAssociatedObject和objc_getAssociatedObject.例如:

#import <objc/runtime.h>
@interface Person (EmailAddress)
@property (nonatomic, readwrite, copy) NSString *emailAddress;
@end

@implementation Person (EmailAddress)

static char emailAddressKey;

- (NSString *)emailAddress {
    return objc_getAssociatedObject(self, 
                                    &emailAddressKey);
}

- (void)setEmailAddress:(NSString *)emailAddress {
   objc_setAssociatedObject(self, 
                            &emailAddressKey,
                            emailAddress,
                            OBJC_ASSOCIATION_COPY);
}
@end

但有人知道做什么objc_getAssociatedObject或objc_setAssociatedObject做什么？我的意思是,我们添加到对象(这里self)的变量存储在哪里？和变量之间的关系self？