Question

I have two categories defined for the same class and have same function but different definition. I want to choose a particular function of a category at runtime on some condition.
Does obj c compiler maintain some book keeping for categories.

I was thinking in terms of C++ (virtual function/Vtable) where these can be achieved using polymorphism. How can I solve such scenario in objective C.

Class MyClass;

File:Myclass+category1.h
@interface MyClass (CategoryOne)
-(void) printCategory()
@end 

File:Myclass+category2.h
@interface MyClass (CategoryTwo)
-(void) printCategory()
@end 

Now I included both the header files in MyClass.m. Is there any possibility of liberty of choosing the particular definition of “printCategory()” at some runtime condition?

Answer 1

No. If two categories implement the same method, it is undefined which one is executed.

From the docs:

There’s no limit to the number of categories that you can add to a class, but each category name must be different, and each should declare and define a different set of methods.