I use ActionBarSherlock with theme Theme.Sherlock.ForceOverflow (for using on pre Honeycomb devices) and I need turn off blue line under my ActionBar....is it possible?
SOLUTION: here
Another way to solve the problem:
actionBar.setBackgroundDrawable(null);
Only solves the problem locally though.
I'm not sure if you can remove the bar but you could change the colour of the bar to match that of the background colour?
If you want to try it try this:
<item name="android:background">@drawable/your_theme_name</item>
<item name="background">@drawable/your_theme_name</item>
That blue line under the ActionBar is part of the background image (which is a 9 patch). Change the background image, or set it to a solid color, and the blue bar will go away.