Question

I created 2 objects subclass from NSObject

AObject, BObject

Is it possible to transfer variables of these 2 objects to a same function?

such as

-(void)myFunction:(AObject *)obj;

-(void)myFunction:(BObject *)obj;

I tested in xcode, it is not allowed.
Is there any replacement method?

Welcome any comment

Thanks
interdev

Answer 1

There are several options. Here are four that come to mind, each with their own pros and cons:

1. Discriminate by signature:

   - (void)myFunctionWithA:(AObject *)obj;
   - (void)myFunctionWithB:(BObject *)obj;
   

2. Declare a parameter of type NSObject * (or id, as suggested in the comments) and query the type inside the function.

3. As above, but constrain it by declaring a common base class BaseObject *, from which AObject and BObject inherit.

4. Combine the base class with a trampoline technique:

   - (void)myFunction:(BaseObject *)base {
       [base myTrampoline:self];
   }
   

   BaseObject declares the abstract method myTrampoline:, which AObject and BObject implement.

Without knowing more about your problem, it’s impossible to say which is best.