4. Installation - TomGrill/gdx-facebook GitHub Wiki

Install gdx-facebook

In case you require debug output:

Gdx.app.setLogLevel(Application.LOG_DEBUG); 

Allocate a new GDXFacebookConfig object and set your APP_ID

GDXFacebookConfig config = new GDXFacebookConfig();
config.APP_ID = "MY_APP_ID_HERE"; // required
config.PREF_FILENAME = ".facebookSessionData"; // optional
config.GRAPH_API_VERSION = "v2.6"; // optional, default is v2.6

Get the GDXFacebook instance:

GDXFacebook facebook = GDXFacebookSystem.install(config);

or when already installed:

GDXFacebook facebook = GDXFacebookSystem.getFacebook();

GDXFacebookSystem.install(config);