No @Navigator.Name annotation found

[Edyazn]

Android application type

Classic Xamarin.Android (MonoAndroid12.0, etc.)

Affected platform version

Visual Studio Community 2022 for Mac Version 17.4.4, Xamarin.Android 13.1.0.1

Description

I try to create custom AndroidX.Navigation.Navigator. My CustomFragmentNavigator implements IName:

public class CustomFragmentNavigator : AndroidX.Navigation.Navigator, AndroidX.Navigation.Navigator.IName
{
    public string Value()
    {
        return "customFragment";
    }

    public Class AnnotationType()
    {
        return Class;
    }
    
    ...
}

Also I create CustomNavHostFragment:

public class CustomNavHostFragment : AndroidX.Navigation.Fragment.NavHostFragment
{
    protected override void OnCreateNavHostController(NavHostController navHostController)
    {
        base.OnCreateNavHostController(navHostController);

        var navigator = new CustomFragmentNavigator(RequireContext(), ChildFragmentManager, GetContainerId());
        navHostController.NavigatorProvider.AddNavigator(navigator);
    }

    int GetContainerId()
    {
        if (Id > 0)
            return Id;

        return Resource.Id.nav_host_fragment_container;
    }
}

When executing Java.Lang.IllegalArgumentException has been thrown (No @Navigator.Name annotation found for CustomFragmentNavigator).

What is analog of attribute @Navigator.Name("customFragment") in Xamarin?

Steps to Reproduce

1. Create custom AndroidX.Navigation.Navigator
2. Create custom AndroidX.Navigation.Fragment.NavHostFragment and add navigator from previous step
3. Use custom NavHostFragment in layout

Did you find any workaround?

No response

Relevant log output

No response

[gmck]

@Edyazn,

About 18 months ago I had

java.lang.IllegalArgumentException: No @Navigator.Name annotation found for NavGraphNavigator. Issue #6928

I had to add the following to proguard.cfg to fix it.

-keepattributes RuntimeVisibleAnnotations
-keep class * extends androidx.navigation.Navigator

I didn't have a custom navigator though.

I'd need to remove those lines and test again to know if they are still required.

[Edyazn]

@gmck, default Navigator works correctly. But I need custom implementation for my case. It looks like Xamarin doesn't support it...

[moljac]

@Edyazn
Can you provide minimal repro sample please?

[Edyazn]

Sample is here: https://github.com/Edyazn/CustomNavigatorIssue

[Edyazn]

@moljac, have you seen my sample?

[moljac]

@Edyazn Yes I have. Thanks.

But I didn't dive in deeper, yet.