Setting a View background based on theme attribute crash the app

I'm trying to set a ListView background color based on the current theme attribute, but it crash every time the ListView is shown.It seems I'm doing something wrong but I can't see what... Here's what I'm doing: First, create the background color: ``` <resources> <color name="userlist_background_light">#fff0f0f0</color> <color name="userlist_background_dark">#ff040404</color> </resources> ``` Second, create attributes for my custom themes: ``` <resources> <attr name="userlist_background" format="reference|color" /> </resources> ``` Third, setting this attribute in my themes: ``` <resources xmlns:android="http://schemas.android.com/apk/res/android"> <style name="Light" parent="Theme.Sherlock.Light"> <item name="userlist_background">@color/userlist_background_light</item> </style> <style name="Dark" parent="Theme.Sherlock"> <item name="userlist_background">@color/userlist_background_dark</item> </style> </resources> ``` And finally, using this attribute in the ListView xml: ``` <ListView android:id="@+id/user_bar" android:layout_width="0dip" android:layout_height="0dip" android:background="?attr/userlist_background" android:cacheColorHint="?userlist_background" android:visibility="gone" /> ``` Even the Eclipse layout view crash. Of course, it works fine if I use a "@color/" directly in the background attribute. It even work if I use say, "?android:attr/colorBackground". The message error is: android.view.InflateException: Binary XML file line #8: Error inflating class android.view.ListView Caused by: android.content.res.Resources$NotFoundException: Resource is not a Drawable (color or path): TypedValue{t=0x2/d=0x7f010068 a=-1} I'm pretty sure I'm doing something wrong, as it works with android attributes, but I haven't be able to find what during my Google searches. I hope you'll be able to help me! Many thanks, Sébastien.