getactionbar in fragment

I  call getactionbar in fragment but the function is not recognized. I search on Google and the solution is very simple.

ActionBar actionBar = getActivity().getActionBar();
   actionBar.setDisplayHomeAsUpEnabled(true);
 

NOTE 

You can control the behaviors and visibility of the action bar with the ActionBar APIs, which were added in Android 3.0 (API level 11). Remember!