[WebAuthenticator] NullReferenceException on CallbackResult

[Hantse]

Description

I create new MAUI Application and i try to use WebAuthenticator.
I initialise everything i see in sample app in repository.
I launch app, click on button and arrive to page for authenticate on web.
Authentication work, and callback is launch to app.
App try to launch, i pass in WebAuthenticationCallbackActivity constructor, but after the application crash, with "NullReferenceException", log are not enough clear to see where that's come.

Repository :
https://github.com/Hantse/maui-webauthenticator

Steps to Reproduce

1. Clone repository https://github.com/Hantse/maui-webauthenticator
2. Launch project as Normal or Blazor
3. Click on button to start authenticate process

Version with bug

Preview 10 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS, Android, Windows

Affected platform versions

Android

Did you find any workaround?

No response

Relevant log output

No response

[enisn]

Same problem occurs:

• Here is my activity:

[Activity(NoHistory = true, LaunchMode = LaunchMode.SingleTop)]
[IntentFilter(new[] { Android.Content.Intent.ActionView },
    Categories = new[] { Android.Content.Intent.CategoryDefault, Android.Content.Intent.CategoryBrowsable },
    DataScheme = CALLBACK_SCHEME)]
public class MyWebAuthenticatorCallbackActivity : Microsoft.Maui.Essentials.WebAuthenticatorCallbackActivity
{
    const string CALLBACK_SCHEME = "myapp";

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
    }
}

• Callback URL is that: myapp://auth-callback

• And the log

...
[monodroid-assembly] open_from_bundles: failed to load assembly System.Security.Cryptography.Algorithms.dll
[monodroid-assembly] open_from_bundles: failed to load assembly System.Security.Cryptography.Primitives.dll
Loaded assembly: /data/data/com.companyname.mauiapp1/files/.__override__/System.Security.Cryptography.Algorithms.dll [External]
Loaded assembly: /data/data/com.companyname.mauiapp1/files/.__override__/System.Security.Cryptography.Primitives.dll [External]
Resolved pending breakpoint at 'OidcClientFactory.cs:43,1' to void MauiApp1.WebAuthenticatorBrowser.<InvokeAsync>d__0.MoveNext () [0x000f0].
[monodroid-assembly] open_from_bundles: failed to load assembly Xamarin.AndroidX.Browser.dll
Loaded assembly: /data/data/com.companyname.mauiapp1/files/.__override__/Xamarin.AndroidX.Browser.dll [External]
Resolved pending breakpoint at 'MainActivity.cs:27,1' to void MauiApp1.MyWebAuthenticatorCallbackActivity.OnCreate (Android.OS.Bundle savedInstanceState) [0x00000].
**System.NullReferenceException:** 'Object reference not set to an instance of an object.'

Logs doesn't help. There is no stacktrace in logs.

Also I've tried to check to find what can be null, I saw savedInstanceState is null but it doesn't matter because there is a check for that here:

maui/src/Essentials/src/WebAuthenticator/WebAuthenticatorIntermediateActivity.android.cs

Line 21 in cf6896e

var extras = savedInstanceState ?? Intent.Extras;

[enisn]

Hi @Hantse

I've found a solution while reviewing source code of WebAuthenticator

It uses CustomTabs:

maui/src/Essentials/src/WebAuthenticator/WebAuthenticator.android.cs

Line 72 in cf6896e

var customTabsActivityManager = CustomTabsActivityManager.From(parentActivity);

So adding following part into your AndroidManifest.xml solved my problem:

  <queries>
    <intent>
      <action android:name="android.support.customtabs.action.CustomTabsService" />
    </intent>
  </queries>

It should be between <manifest> tags.

After adding it, NullReferenceException was solved 👍

[Hantse]

Hello, I try your solution thx :)

[jfversluis]

Could someone please confirm this is still an issue in the current releases?

[enisn]

Could someone please confirm this is still an issue in the current releases?

It's working on all platforms with preview.14 right now.

Only Windows has a problem and it has own issue: (#2702)

[jfversluis]

Perfect, thanks @enisn! Then I'm going to assume most of this works now unless someone tells me otherwise :)