Adding Properties to an Objective-C Category Revisted

Example1.m

	static char kDHStyleKey;

	@interface UIView (DHStyleManager)
	@property (nonatomic, copy) NSString* styleName;
	@end

	@implementation UIView (DHStyleManager)
	@dynamic styleName;
	- (void)setStyleName:(NSString *)styleName
	{
		objc_setAssociatedObject(self, &kDHStyleKey, styleName, OBJC_ASSOCIATION_COPY);
	}

	- (NSString*)styleName
	{
		return objc_getAssociatedObject(self, &kDHStyleKey);
	}

	@end

Example2.m

	@interface UIView (DHStyleManager)
	@property (nonatomic, copy) NSString* styleName;
	@end
	
	@implementation UIView (DHStyleManager)
	ADD_DYNAMIC_PROPERTY(NSString*,styleName,setStyleName);
	
	@end

Example3.m

	#define ADD_DYNAMIC_PROPERTY(PROPERTY_TYPE,PROPERTY_NAME,SETTER_NAME) \
	@dynamic PROPERTY_NAME ; \
	static char kProperty##PROPERTY_NAME; \
	- ( PROPERTY_TYPE ) PROPERTY_NAME \
	{ \
		return ( PROPERTY_TYPE ) objc_getAssociatedObject(self, &(kProperty##PROPERTY_NAME ) ); \
	} \
	\
	- (void) SETTER_NAME :( PROPERTY_TYPE ) PROPERTY_NAME \
	{ \
		objc_setAssociatedObject(self, &kProperty##PROPERTY_NAME , PROPERTY_NAME , OBJC_ASSOCIATION_RETAIN); \
	} \