Q:

Cannot unlock "UITabBarController.h" for editing

I need to change the class of UITabBarController to a custom one. But Xcode won't allow me to do that. It's saying:    

The file “UITabBarController.h” could not be unlocked.
Could not add write permission to the file because you do not own it. Try modifying the permissions of the file in the Finder or Terminal.    

I have set the permissions to read and write to the folder in Finder (I also have "Apply to enclosed items" ref this post).
Does anyone have some idea of what else I can try?

A:

It seems like what you need to do is subclass a UITabBarController and then use this instead.
Note that you can override UITabBarController methods and properties in this subclass as you need.
Apple doesn't allow you to modify their classes as part of UIKit, unlike other third party frameworks.

