Enabling Google login in your Xamarin forms app allows users to easily sign in using their existing Google account credentials. This provides a smooth and familiar login experience for your users. Implementing Google login requires integrating the Google Sign-In SDK into your Xamarin forms project.
The key steps involved are:
- Register your app with Google Developer Console.
- Install the Xamarin.Google.iOS.SignIn and Xamarin.Google.Android.SignIn NuGet packages.
- Configure the Android and iOS projects.
- Add a login button to your app UI.
- Handle the login and logout events.
In this comprehensive guide, we will walk through how to implement Google sign in step-by-step in a Xamarin forms app. We will cover:
Registering with Google Developer Console
To use Google login, you first need to register your app in the Google Developer Console and get OAuth 2.0 client IDs for Android and iOS. Here are the steps:
- Go to the Google Developers Console at https://console.developers.google.com and log in with your Google account.
- Create a new project by clicking on the dropdown at the top left and selecting New Project.
- Give your project a name and continue. This can be anything you want.
- Once the project is created, go to Credentials > OAuth consent screen. Select External and click Create.
- Enter an App name and Save.
- Next, go to Credentials > Create credentials > OAuth client ID.
- Select Android and enter your app package name. Continue.
- Download the generated config file. This contains the Android client ID.
- Repeat the last two steps for iOS, entering your iOS bundle ID.
You should now have an Android client ID and iOS client ID from Google. Make sure to note these down as we’ll need them later.
Installing NuGet Packages
The Google Sign-In SDK is available as NuGet packages for Xamarin apps. You need to install them in both the Android and iOS projects:
- Xamarin.Google.iOS.SignIn – Contains Google Sign-In bindings for iOS
- Xamarin.Google.Android.SignIn – Contains Google Sign-In bindings for Android
To install these packages, right click on each project in Visual Studio and choose Manage NuGet Packages. Search for the packages by name and install them.
Configuring Android Project
In the Android project, open MainActivity.cs and make the following changes:
- Add a using statement for Google.iOS.SignIn:
- Set the client ID on the sign in options:
- Override the OnActivityResult method to handle sign in:
- Add a using statement for Google.iOS.SignIn:
- Configure the sign in options:
- Handle sign in callback in OpenUrl:
- Adding a Button to your XAML layout
- Setting the Text property, e.g. “Login with Google”
- Adding a Clicked handler that calls the sign in method
using Xamarin.Google.Android.SignIn;
SignInOptions signInOptions = new SignInOptions.Builder(GoogleSignInOptions.DefaultSignIn)
.RequestIdToken(clientId)
.RequestEmail()
.Build();
GoogleSignInOptions.Default.ClientId = clientId;
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
AuthenticationHelper.OnAuthCompleted(requestCode, resultCode, data);
}
This handles the callback from the Google login UI. The client ID should be the one you obtained from Google Developer Console.
Configuring iOS Project
In the iOS project, open AppDelegate.cs and make these changes:
using Google.SignIn;
SignIn.SharedInstance.ClientId = clientId;
public override bool OpenUrl(UIApplication app, NSUrl url, NSDictionary options)
{
return SignIn.SharedInstance.HandleUrl(url);
}
Again, set the client ID from Google Developer Console. This completes the basic configuration.
Adding Login Button
To actually allow users to sign in, you need to add a login button to your app UI. This can be done by:
For example:
<Button Text="Login with Google" Clicked="OnLoginButtonClicked" />
void OnLoginButtonClicked(object sender, EventArgs e)
{
LoginWithGoogle();
}
This will trigger the Google login process when tapped.
Handling Login and Logout
The last step is to implement the LoginWithGoogle and Logout methods which will sign the user in and out:
LoginWithGoogle method
public async Task LoginWithGoogle()
{
try
{
await AuthenticationHelper.AuthenticateAsync();
//Retrieve user info
}
catch (Exception ex)
{
//Error handling
}
}
This calls the AuthenticationHelper class to bring up the Google login UI. On successful login, you can retrieve the user’s profile information.
Logout method
public void Logout()
{
AuthenticationHelper.SignOut();
}
This signs the user out of their Google account.
With this, you will have a fully working Google login in your Xamarin forms app!
Conclusion
Implementing Google sign in authentication is a great way to provide seamless login access in your cross-platform Xamarin forms apps. Key steps include registering your app, configuring the Android and iOS projects, adding a login button, and handling login/logout logic. With just a few lines of platform-specific code, you can enable this popular login option for your users.
| Step | Description |
|---|---|
| Register with Google | Create app in Google Developer Console to get client IDs |
| Install NuGet packages | Xamarin.Google.iOS.SignIn and Xamarin.Google.Android.SignIn packages |
| Configure Android project | Set client ID and handle sign in callback |
| Configure iOS project | Set client ID and handle sign in callback |
| Add login button | Button in XAML layout to trigger login process |
| Handle login/logout | Call AuthenticationHelper to sign user in/out |
Following these steps will enable a smooth Google login for your Xamarin forms users and make it quick and easy for them to access their accounts.
Frequently Asked Questions
Do I need to create separate Google projects for Android and iOS?
No, you only need one Google Developer Console project. Within that, you will create an OAuth client ID for Android using your package name and another for iOS with your bundle ID.
Where do I get the Google client IDs from?
When you create OAuth client IDs for Android and iOS in Google Developer Console, it will generate and show you the client IDs which you will need to configure the sign in code.
How do I customize the Google sign in button?
The Xamarin bindings include a SignInButton view you can use. It has properties like ColorScheme and Size to customize the button style. You can also create your own button and call the LoginWithGoogle method.
Is there a way to only allow users from a certain Google Workspace domain to sign in?
Yes, when you create the OAuth client ID in Developer Console, enable the “Restrict to domain” option and enter your Google Workspace domain. This will restrict sign in only to users from that domain.
How do I get user information after login?
The AuthenticationHelper provides events like OnAuthSucceeded that passes the user profile information including name, email, ID token etc. which you can retrieve after a successful login.
Can I customize the scopes requested for sign in?
Yes, the SignInOptions while configuring allows you to specify scopes like email, profile etc. So you can request only the user information your app needs.
How can I handle login errors gracefully?
Use try-catch blocks when calling the AuthenticationHelper login methods. It surfaces errors like SignInCanceledException for scenarios like login cancelation which you can catch and handle.
Code Samples
Here are some code samples for commonly used patterns when implementing Google sign in:
Restrict sign in to domain users
SignInOptions signInOptions = new SignInOptions.Builder(GoogleSignInOptions.DefaultSignIn)
.SetHostedDomain("mycompany.com")
.RequestIdToken(clientId)
.Build();
Sign in with specific scopes
SignInOptions signInOptions = new SignInOptions.Builder(GoogleSignInOptions.DefaultSignIn)
.RequestScopes(new[] { Scope.UserProfile })
.RequestIdToken(clientId)
.Build();
Handle cancellation error
try
{
await AuthenticationHelper.AuthenticateAsync();
}
catch (SignInCanceledException)
{
// Show message to user
}
Retrieve user info
var userInfo = AuthenticationHelper.UserInfo;
string name = userInfo.FullName;
string email = userInfo.EmailAddress;
Troubleshooting
Here are some common issues faced when implementing Google sign in and how to resolve them:
API exception with status: 10
– Indicates invalid client ID
– Double check the client IDs set in Android and iOS config
No UI shown on button click
– Ensure you have configured OnActivityResult callback in Android
– And OpenUrl override in AppDelegate for iOS
User info is null after login
– Call AuthenticationHelper.OnAuthSucceeded event to get user info
– Do not directly query UserInfo property
Login works but immediately logs out
– App is likely missing scopes required for access token
– Ensure you request adequate scopes in SignInOptions
Forbidden error when accessing Google APIs
– Request an ID token when configuring SignInOptions
– Pass this ID token to Google API clients
App rejects GoogleSignIn.bundle
– Add LSApplicationQueriesSchemes entry for com.googleusercontent.apps.
–
Following these troubleshooting tips should help resolve most common integration issues.
Summary
In this guide we walked through implementing Google sign in a Xamarin forms app step-by-step including:
- Registering app with Google Developer Console
- Installing required NuGet packages
- Configuring Android and iOS projects
- Adding login button to UI
- Integrating login and logout logic
- Customizing scopes and auth options
- Retrieving user information
- Troubleshooting issues
Google login integration greatly improves the sign in experience in cross-platform apps. With the detailed steps and code samples outlined here, you should have all you need to get Google sign in working securely in your Xamarin forms project.