Android set background color of preference category

[admin]

I try to customize the background color of preference categories. I already changed the background color of a preferences itself but I can't find a way how to change the the categories background color.

I found two ways but they don't works for me:
<a href="https://stackoverflow.com/questions/7048089/changing-the-preference-category-label-color-background">changing the preference category label color background</a>

Through <a href="https://stackoverflow.com/questions/5571603/change-preferenceactivity-text-color">this link</a>, i found <a href="http://udinic.wordpress.com/2011/08/18/dress-up-your-preferenceactivity/" rel="nofollow noreferrer">this</a>, but nothing I've tried worked for me. These layout snippet is what I've tried so far:

<resources>
    <style name="setBackgroundTheme" parent="android:Theme">
        <item name="android:background">@color/darkbluelogo</item>
    </style>
</resources>

In

onCreate

method I set the theme with:

setTheme(R.style.setBackgroundTheme);