How to add Google sign-in to your app

Google sign in allows your users to sign in to your application using their Google credentials. This option offers several advantages to your user, including the following:

• Confidence because they're using Google
• Convenience since they can use their existing account

There are also several advantages for you, the developer:

• Convenience of not having to write your own authentication server
• More users logging in to your app 

This recipe will walk you through the process of adding Google sign-in to your application. Here's a screenshot showing the "GoogleSignin" button in the application that we'll create in the recipe:

Getting ready

Create a new project in Android Studio and call it GoogleSignIn. Use the default Phone & Tablet option and select Empty Activity when prompted for Activity Type.

Google sign-in uses the Google Services plugin, which requires a Google Services Configuration file, which is available from the Google Developer Console. To create the...