AndroidX.Credentials ICredentialManagerCallback wrong parameter types.

[Uwe Schaller]

Android application type

Classic Xamarin.Android (MonoAndroid12.0, etc.), Android for .NET (net6.0-android, etc.)

Affected platform version

VS Mac 2022 17.6.9

Description

The interface ICredentialManagerCallback.cs OnError and OnResult use Java.Lang.Object parameter type.
It should be

onResult(GetCredentialResponse result)
and
onError(GetCredentialException e)

Unfortunately, It is not possible cast.
So, it's impossible to get a proper error message on the c# level.

Steps to Reproduce

ICredentialManager credentialManager = CredentialManager.Companion.Create(this.Context);
                CreatePublicKeyCredentialRequest createPublicKeyCredentialRequest = new CreatePublicKeyCredentialRequest(passkeyRequestVO.RequestJson);
                credentialManager.CreateCredentialAsync(this.Context, createPublicKeyCredentialRequest, new Android.OS.CancellationSignal(), this, this);

void ICredentialManagerCallback.OnError(Java.Lang.Object e){   System.Diagnostics.Debug.WriteLine("ICredentialManagerCallback.OnError: " + e);}
void ICredentialManagerCallback.OnResult(Java.Lang.Object result){    System.Diagnostics.Debug.WriteLine("ICredentialManagerCallback.OnResult");}

Did you find any workaround?

nope

Relevant log output

No response

[Jonathan Pobst]

You should be able to use JavaCast to cast to the correct type:

void ICredentialManagerCallback.OnResult (Java.Lang.Object result) 
{
    var r = result.JavaCast<GetCredentialResponse> ();
}

[Uwe Schaller]

You should be able to use JavaCast to cast to the correct type:

void ICredentialManagerCallback.OnResult (Java.Lang.Object result) 
{
    var r = result.JavaCast<GetCredentialResponse> ();
}

Thank you @jpobst that works. It's inconvenient, because I can't do type switch. Only works for the explicit exception type.
In my case
var r = e.JavaCast<CreatePublicKeyCredentialDomException>();
It throws an exception if the type does not match. So to cover all available exceptions types, it will be a big block of code.

Same interface OnResult works better, here it's Java.LangObjcte as well. But I can do a c# cast on the CreatePublicKeyCredentialResponse.

if (result is CreatePublicKeyCredentialResponse cpkcr) { ... }

Something is wrong with the exceptions themself.