Which you think is the best way of doing a wizard like application (user can navigate between screens with a next and back button, and each screen has to save some state dat
9 years ago this was obviously a very different kettle of fish - but I think the best way to do this now is with Fragments.
Have a Fragment for each 'page' in the wizard, letting it handle its own lifecycle and state.
Change page from within each Fragment with Fragment.getFragmentManager() - this returns the FragmentManager from the parent Activity, allowing the Fragment to replace itself.