I can set Android's ActionBar background color easily via this code on colors.xml
<resources>
<color name="colorPrimary">#ffffc003</color>
<color name="colorPrimaryDark">#ffffffff</color>
<color name="colorAccent">#ff009486</color>
</resources>
I figured I could set the text to black adding this part:
<color name="textColorPrimary">#ff000000</color>
But it has no effect, so the background is white and the text is also white.
BTW it would be nice to allow programatically change these values, so different forms could style their own action bars.
[EDIT] The first image has android.statusbar_hidden=true. The second, use colors.txt with colorPrimaryDark as white. And the third is the result I would like to have: a status bar with white background and black foreground.