6

I've implemented the Xamarin.Auth sample code to authenticate with google's identity provider on Android. I'm successfully navigated to the Google login page using the device's Chrome browser where I can enter my credentials. I successfully authorize with Google but the Chrome Custom Tabs doesn't close when it redirects back to my app, i.e., I'm left looking at the google search in the chrome browser. If I close the browser I can see my app again with the user details returned from google's identity provider displayed.

Why is Chrome's custom tabs not closing on redirect from the Google identity provider, and how can I get it to close using Xamarin Forms and Xamarin.Auth?

James B
  • 8,975
  • 13
  • 45
  • 83

1 Answers1

9

You can go back to your app if you add this code to the end of OnCreate method in the class that captures the Redirect (CustomUrlSchemeInterceptorActivity) in Xamarin.Auth example in Android

new Task(() =>{
         StartActivity(new Intent(Application.Context,typeof(MainActivity)));
     }).Start();

Where MainActivity is the name of your main Activity class in Android. To be more exact here is a complete class that you can inherit for each redirection you intercept

public class UrlSchemeInterceptor : Activity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        try
        {
            base.OnCreate(savedInstanceState);

            // Convert Android.Net.Url to Uri
            var uri = new Uri(Intent.Data.ToString());
            new Task(() =>
            {
                var intent = new Intent(ApplicationContext, typeof(MainActivity));
                intent.AddFlags(ActivityFlags.IncludeStoppedPackages);
                intent.AddFlags(ActivityFlags.ReorderToFront);
                StartActivity(intent);

            }).Start();

            // Load redirectUrl page
            AuthenticationState.Authenticator.OnPageLoading(uri);
            Finish();

        }
        catch (Exception e)
        {
            Console.WriteLine(e);
        }
    }

}

public class AuthenticationState
{
    public static WebAuthenticator Authenticator;
   /*This static field is used to store the object
   from OAuth1Authenticator or OAuth2Authenticator
   upon initialization in the UI (Xamarin forms or Android or iOS).
   For example:
   var authenticatorObject = new  OAuth2Authenticator (YOUR PARAMETERS);
   AuthenticationState.Authenticator = (WebAuthenticator)authenticatorObject;
    var presenter = new OAuthLoginPresenter();
        presenter.Login(authenticatorObject);
    */
}

For example in Google Case

[Activity(Label = "YOURLABEL", NoHistory = true, LaunchMode = LaunchMode.SingleTop)]
[IntentFilter( new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault, Intent.CategoryBrowsable },
    DataSchemes = new[]
    {
        "com.googleusercontent.apps.",// YOUR GOOGLE ID INVERTED
    },
    DataPaths = new[]
    {
        "/oauth2redirect",
    })]
public class GoogleUrlSchemeInterceptorActivity : UrlSchemeInterceptor { }
Ahmed Samy Moursi Hashwa
  • 579
  • 1
  • 3
  • 20
  • Doesn't work for me. `public class GoogleAuthInterceptor : Activity { protected override void OnCreate(Bundle savedInstanceState) { base.OnCreate(savedInstanceState); Android.Net.Uri uri_android = Intent.Data; Uri uri_netfx = new Uri(uri_android.ToString()); MainActivity.Auth?.OnPageLoading(uri_netfx); Finish(); new Task(() => { StartActivity(new Intent(Application.Context, typeof(MainActivity))); }).Start(); } }` – Casperonian Mar 28 '18 at 14:52
  • I clarified the example more and added code from a project that worked for me. – Ahmed Samy Moursi Hashwa Mar 28 '18 at 17:07
  • Hi Ahmed, no. still not working for me. I implemented the exact same code per your recommendation. However, I could not find any library that implements AuthenticationState, so I replace it with the following: Instead of this: `AuthenticationState.Authenticator.OnPageLoading(uri);` I implemented this: `MainActivity.Auth?.OnPageLoading(uri);` – Casperonian Mar 29 '18 at 22:40
  • Yes. If you say that Auth is a static object that holds the authenticator object then it should work. Any way I added the missing part. Enjoy. – Ahmed Samy Moursi Hashwa Mar 30 '18 at 04:06