Facebook Login allows you to obtain a token to access Facebook's API on behalf of someone using your app. You can use this feature in place of building your own account system or to add Facebook services to your existing accounts. To properly handle Facebook Login using the Facebook for Android app, make the following changes in the App Dashboard . Create a Facebook App URL to create FB App: https://developers.facebook.com/?advanced_app_create=true Once created, note down the app ID shown at the top of the dashboard page. You'll need to add this to your project files. Next, you will also need to associate your Android keys hashes with the app. The key hash is used by Facebook as a security check for authenticity. By default, the app's package is signed with a machine specific debug key. When publishing the app it is typically signed with a different, release key. Therefore, you want to make sure you have the hashes of all the related keys set on...