Prettier presentation hint handling in MvvmCross

ExamplePlatformPresenter.cs

public class YourPlatformSpecificPresenter : PlatformSpecificMvxPresenter, IMvxViewPresenterWithDelegate {
    public MvxViewPresenterDelegate Delegate { get; } = new MvxViewPresenterDelegate();
    
    public YourPlatformSpecificPresenter() {
        this.AddPresentationHintHandler<MyPresentationHint>(hint => {
            // Do something
        });
    }
    
    public override void ChangePresentation(MvxPresentationHint hint) {
        if (!Delegate.HandleChangePresentation(hint)) {
            base.ChangePresentation(hint);
        }
    }
}

IMvxViewPresenterWithDelegate.cs

public interface IMvxViewPresenterWithDelegate : IMvxViewPresenter {
    MvxViewPresenterDelegate Delegate { get; }
}

MvxViewPresenterDelegate.cs

public class MvxViewPresenterDelegate {
    private readonly Dictionary<Type, Action<MvxPresentationHint>> _presentationHintHandlers = new Dictionary<Type, Action<MvxPresentationHint>>();

    public void AddPresentationHintHandler<THint>(Action<THint> action) where THint : MvxPresentationHint {
        _presentationHintHandlers[typeof(THint)] = hint => action((THint)hint);
    }

    public bool HandleChangePresentation(MvxPresentationHint hint) {
        Action<MvxPresentationHint> handler;

        if (_presentationHintHandlers.TryGetValue(hint.GetType(), out handler)) {
            handler(hint);
            return true;
        }

        return false;
    }
}

MvxViewPresenterWithDelegateExtensions.cs

public static class MvxViewPresenterWithDelegateExtensions {
    public static void AddPresentationHintHandler<THint>(this IMvxViewPresenterWithDelegate viewPresenter, Action<THint> action) where THint : MvxPresentationHint {
        viewPresenter.Delegate.AddPresentationHintHandler(action);
    }
}