Category 增加字段

NSObject+AssociatedObject.h

@interfaceNSObject(AssociatedObject)

@property(nonatomic,strong)idassociatedObject;

@end

NSObject+AssociatedObject.m

@implementationNSObject(AssociatedObject)

@dynamicassociatedObject;

-(void)setAssociatedObject：(id)object{

      objc_setAssociatedObject(self,@selector(associatedObject),object,OBJC_ASSOCIATION_RETAIN_NONATOMIC);

}

-(id)associatedObject{

       returnobjc_getAssociatedObject(self,@selector(associatedObject));

}