Android: How to recreate Action bar when fragment changed

Question

I have an activity showing a few fragments. Activity view contains only ViewPager initialized with custom FragmentPagerAdapter. This adapter provide navigation among 3 fragments

Answer 1

If you are using ActionBar tabs, You would like to see this answer:

How can I change Action Bar actions dynamically?

Answer 2

Finally I couldn't find any sound way to achieve this.

The best would be to make actionbar a part of fragment, not activity, but it's impossible.

I end up with clearing actionbar menu and title when swipe begins(you can set special listener in PageView) and setting menu and title again when swipe complete and new fragment are shown.

In gives some time lag and actionbar looks strangely empty during swipe, but it's best you can do.
Android API is c...

Answer 3

It can be done by implementing onCreateOptionsMenu and calling setHasOptionsMenu(true) in the onAttach callback in each fragment and change the actions accordingly.

To show the fragment without any actions setHasOptionsMenu(false) in it

Answer 4

You can ask android to re-create the actionbar before it automatically does by calling invalidateOptionsMenu();

Do this somewhere close to the point where you change fragments to try and decrease the 'lag' between the fragment and actionbar changing.

Edit

a complete solution may look like this:

class activity extends Activity{

private void switchFragment(){

...do fragment changing stuff

activity.invalidateOptionsMenu();

}

}

class someFragment extends Fragment{

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
{
    super.onCreateOptionsMenu(menu, inflater);
    menu.clear();


    //fragment specific menu creation
}

}

whichever fragment is open during the

activity.invalidateOptionsMenu();

will then call its

 onCreateOptionsMenu

and you can do fragment specific menu creation in there