This application is the result of a tutorial available at http://devleader.ca/2013/11/04/fragments-tabbed-android user-interface/.
If you're new to Android programming or simply looking for a refresher on how to use tabs and fragments together to create a user interface, this application is probably worth checking out. It's incredibly simple and there's no shiny bells and whistles added to the application. The user interface is comprised of two tabs that you can switch between and the content within each tab is changed when you press the tabs.
Instructions for how to create a similar tabbed user interface are available at http://devleader.ca/2013/11/04/fragments-tabbed-android-user-interface/. You can also get to the corresponding tutorial article by using the application.