Objective C: how to inherit category methods loaded in a parent class?

问题

In my project, I am using the NSObject+Properties.h category (see aqtoolkit: https://github.com/AlanQuatermain/aqtoolkit/blob/master/Extensions/NSObject%2BProperties.h)

I then have a class that I declare as

#import <Foundation/Foundation.h>
#import "NSObject+Properties.h"

@interface GFDictionaryInitiable : NSObject
...

I then have several subclasses of GFDictionaryInitiable, such as GFRestaurant:

#import <Foundation/Foundation.h>

#import "GFDictionaryInitiable.h"

@interface GFRestaurant : GFDictionaryInitiable
...

My problem is that I cannot access methods defined in the NSObject+Properties category in my subclasses. For example I get the error:

-[GFRestaurant hasPropertyNamed:]: unrecognized selector sent to instance 0x2e57240

How can I have all my subclasses 'inherit' the category's methods that are loaded in the parent class?

回答1:

As you get a runtime exception, and not a compiler error, I assume that you forgot to add "NSObject+Properties.m" to your target. Select the file and check the "Target Membership" checkbox in the File inspector.

回答2:

Just add:

#import "NSObject+Properties.h"

to your sub classes .h files.

来源：https://stackoverflow.com/questions/19432324/objective-c-how-to-inherit-category-methods-loaded-in-a-parent-class