Fixed Button below a scrollable ListView

I have a scrollable ListView with items (like in http://developer.android.com/resources/tutorials/views/hello-listview.html). I am using an ArrayAdapter for the items and use it as a parameter in setListAdapter. Now I would like to add a button at the bottom of the screen, which does not scroll with the list. Could someone give me some hints or post a code snippet how it could possibly be done?