FirebaseAuthActivity includes necessary FirebaseAuth functions such as sign in and sign out for ease of use.
The main functions are to sign in / sign up with Email and Password or sign in with Google account (with GoogleApiClient) and using FirebaseDatabase to store signed-in accounts.
To use FirebaseAuth service, you need to visit Firebase console and add a project with same package name as your Android project package name (Example: com.google.firebase).
Then it will let you download a google-services.json file. Download and place it in app folder.
In build.gradle of project
classpath 'com.google.gms:google-services:3.0.0'In build.gradle of app
compile 'com.google.firebase:firebase-database:10.0.1'
compile 'com.google.firebase:firebase-auth:10.0.1'
compile 'com.google.android.gms:play-services-auth:10.0.1'and at the end
apply plugin: 'com.google.gms.google-services'Check them in build.gradle and app/build.gradle