Android supports resource selectors based on qualifiers. For example to use a special layout file for activity_main.xml on a tablet in landscape mode you would typically define a layout file also called activity_main.xml in the layout-sw600-land folder.
Instead of using this approach you can use use XML layout references. With this approach you define a reference to a file for a defined layout name.
To use the approach for our example create the following refs.xml file in the values-sw600-land folder.
<?xml version="1.0" encoding="utf-8"?> <resources> <item type="layout" name="activity_main">@layout/activity_second</item> </resources>
This file defines that if the layout with the name activity_main is used it should point to the real file activity_second.
So basically you have a second way of configuring which layout file should be used under which condition. I case you have a complex setup of different layout file you may want to use these references to avoid duplication of the layout files in different folders.