This open source Java library allows you to integrate Facebook into your Android application. Except as otherwise noted, the Facebook Android SDK is licensed under the Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0.html)
This library includes three sample applications to guide you in development.
simple: A bare-bones app that demonstrates authorization, making API calls, and invoking a dialog.
stream: This slightly beefier application lets you view your news feed.
Hackbook: This includes Single Sign On implementation (SSO), sample API calls, and advanced features like Get new Permissions, Run sample FQL Query and Graph API Explorer. Check out Hackbook for Android