Question

I have a class (MyClass) with a lot of methods. Consequently, the .m file has become quite difficult to read. I’m relatively new to Objective-C (having come from REALbasic) and I was wondering if it’s possible to put some of the methods in MyClass into different files and then include them in the class. How would I go about this in Xcode?

Answer 1

Yes it is possible and fortunately this can be done easily in Objective-C with Categories.

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Say you have your base class MyClass.

@interface MyClass : NSObject
-(void) methodA;
@end

And the according implementation file (not relevant here).

Then you can create a category by defining a new interface in a new header file:

// the category name is in parenthesis, can be anything but must be unique
@interface MyClass (extended) 
-(void) methodB;
@end

and the implementation file:

@implementation MyClass (extended)
-(void) methodB {

}
@end

Common convention to name these files is ClassToAddMethodsTo+CatgoryName, i.e.:

MyClass+extended.h
MyClass+extended.m

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Group related functionality into categories and give it a meaningful name.