How to hide the ActionBar from app and show only the flag "back", or to put transparent, but showing only the back button? I want to remove the white part and put the flag white. Thanks!

How to hide the ActionBar from app and show only the flag "back", or to put transparent, but showing only the back button? I want to remove the white part and put the flag white. Thanks!

try -->
getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
yourActionBarid.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
yourActionBarid.setElevation(0);
Note
Add getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY); before super.onCreate(savedInstanceState);