What is the meaning of addToBackStack with null parameter?

Question

I have a customer code. There is only one activity for all of the fragments i.e. the single activity is managing all the fragments.

This activity contains the follow

Answer 1

Your answers are deprecated. If you don't want to add fragments to back stack, you should use below snippet of code:

    public static void replaceFragment (@NonNull FragmentManager fragmentManager,
            @NonNull Fragment fragment, int frameId){

        checkNotNull(fragmentManager);
        checkNotNull(fragment);
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(frameId, fragment);
        transaction.disallowAddToBackStack(); // <-- This makes magic!
        transaction.commit();
    }

Below you have cute example of how use it:

GameFragment fragment = GameFragment.newInstance(mGameObject, currentQuestion);
ActivityUtils.replaceFragment(getFragmentManager(), fragment, R.id.main);