google_sign_in_android

The Android implementation of google_sign_in.

Usage

This package is endorsed, which means you can simply use google_sign_in normally. This package will be automatically included in your app when you do, so you do not need to add it to your pubspec.yaml.

However, if you import this package to use any of its APIs directly, you should add it to your pubspec.yaml as usual.

Integration

To use Google Sign-In, you'll need to register your application, either using Firebase, or directly with Google Cloud Platform.

If you are use the google-services.json file and Gradle-based registration system, no identifiers need to be provided in Dart when initializing the GoogleSignIn instance when running on Android, as long as your google-services.json contains a web OAuth client entry.
If you are not using google-services.json, you need to pass the client ID of the web application you registered as the serverClientId when initializing the GoogleSignIn instance.

You will also need to enable any OAuth APIs that you want, using the Google Cloud Platform API manager. For example, if you want to mimic the behavior of the Google Sign-In example app, you'll need to enable the Google People API.

Troubleshooting

If you encounter persistent errors, check that you have followed all of the registration steps in the instructions above. Common signs of configuration errors include:

GoogleSignInExceptions with a code of GoogleSignInExceptionCode.clientConfigurationError.
Unexpected GoogleSignInExceptions with a code of GoogleSignInExceptionCode.canceled after selecting an account during the authentication process.
- Some configuration errors will cause the underlying Android CredentialManager SDK to return a "canceled" error in this flow, and unfortunately the google_sign_in plugin has no way to distinguish this case from the user canceling sign-in, so cannot return a more accurate error message.
Sign-in working in one build configuration but not another.

Common sources of configuration errors include:

Missing or incorrect signing SHA for one or more build configurations.
Incorrect Android package name on the server side.
Missing or incorrect serverClientId.

If you are using google-services.json and recieve a "serverClientId must be provided on Android" error message, check that:

Your google-services.json contains a web OAuth client, which should be an oauth_client entry with client_type: 3. This should have been created automatically when enabling Google Sign In using the Firebase console, but if not (or if it was later removed), add a web app to the project and then re-download google-services.json.
You correctly followed all of the Gradle configuration steps in the Firebase integration documentation.