How to make the navigation bar transparent

I have taken this from the change log for Android KitKat (4.4):

Translucent system bars

You can now make the system bars partially translucent with new themes, Theme.Holo.NoActionBar.TranslucentDecor and Theme.Holo.Light.NoActionBar.TranslucentDecor. By enabling translucent system bars, your layout will fill the area behind the system bars, so you must also enable fitsSystemWindows for the portion of your layout that should not be covered by the system bars.

If you're creating a custom theme, set one of these themes as the parent theme or include the windowTranslucentNavigation and windowTranslucentStatus style properties in your theme.

Hope this helps get you started.

I used your trevor-e's answer, by creating a custom theme in my styles.xml

<style name="Theme.HomeScreen" parent="android:Theme.Holo.NoActionBar.TranslucentDecor">
 <item name="android:windowBackground">@android:color/transparent</item>
             <item name="android:windowNoTitle">true</item> 
        </style>

and then you can set the theme from the manifest

<activity
            android:name="MyActivity" 
            android:launchMode="singleTask"
            android:screenOrientation="portrait"
            android:theme="@style/Theme.HomeScreen" >
     </activity>