I was trying to achieve something else but I needed a solution similar to this. I needed to draw an opaque layer covering the whole screen, even the action bar–sort of like a dialog. I did so this way:
ViewGroup vg = (ViewGroup)(getWindow().getDecorView().getRootView());
vg.addView(myNewView, params);
this can be used to draw anything anywhere on the screen.
UPDATE: You really shouldn’t be using ActionBar anymore, you wouldn’t have this issue in the first place if you were using Toolbar like Android recommends. Toolbar would go inside your activity xml like a regular view and you can can do whatever you want to it. And its fully backwards compatible.
https://developer.android.com/training/appbar/setting-up