ios - 为NSString创建标签

Question

我正在尝试通过创建类别来为NSString提供标签:

。H:

@property (nonatomic, copy) NSString *stringTag;

.m:

- (NSString *)stringTag
{
    return objc_getAssociatedObject(self, CFBridgingRetain(kStringTagKey));
}
- (void)setStringTag:(NSString *)stringTag
{
    objc_setAssociatedObject(self, CFBridgingRetain(kStringTagKey), stringTag, OBJC_ASSOCIATION_COPY_NONATOMIC);
}

但是我得到这些错误:

Answer 1

您需要添加:

#import <objc/runtime.h>