If you want to customize your ActionBarSherlock follow this steps:
1. Create in values folder a new file style.xml
2. In style.xml file determine your styles you want for ActionBarSherlock e.g. :
<?xml version="1.0" encoding="UTF-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">
<style name="Theme.Styled" parent="Theme.Sherlock.Light.DarkActionBar">
<item name="actionBarStyle">@style/Widget.Styled.ActionBar</item>
<item name="android:actionBarStyle">@style/Widget.Styled.ActionBar</item>
</style>
<style name="Widget.Styled.ActionBar" parent="Widget.Sherlock.Light.ActionBar.Solid.Inverse">
<item name="background">@drawable/bgraund</item>
<!-- <item name="android:background">@drawable/top_bar</item> -->
<item name="backgroundSplit">@drawable/bgraund</item>
<item name="android:background">@drawable/bgraund</item>
</style>
</resources>
3. In your AndroidManifest.xml determine this your custom style that you just created in style.xml:
<application android:icon="@drawable/adsurfer_icon"
android:label="@string/app_name"
android:debuggable="true"
android:name=".app.AdsurferApplication"
android:theme="@style/Theme.Styled" >
I've found helpful info on this topic in this article: