I believe a popular way to declare "private methods" in Objective-C is to create its class extension and declare methods that you would like to make as private.
I would like to know more in detail on how an class extension makes the methods work as private.
- Update: I asked this question with the term empty category which is incorrect. I now changed it as class extension
That's because you create your empty category in your implementation file, not your header file so other classes can't access it.
That's not an "empty category", it's a class extension. Read Bbum's explanation of them at the link I provided.