[Navigation] Would you like me to contribute the SelectorBarNavigator?

[xperiandri]

What would you like to be added:

SelectorBarNavigator

Why is this needed:

To navigate using SelectorBar

For which Platform:

• iOS
• Android
• WebAssembly
• WebAssembly renders for Xamarin.Forms
• Windows

using Uno.Extensions.Navigation.Regions;

using Windows.Foundation;

/// <summary>
/// SelectorBar control region navigator
/// </summary>
public class SelectorBarNavigator : SelectorNavigator<SelectorBar>
{
    /// <summary>
    /// Initializes a new instance of the <see cref="SelectorBarNavigator"/> class.
    /// </summary>
    public SelectorBarNavigator(
        ILogger<SelectorBarNavigator> logger,
        IDispatcher dispatcher,
        IRegion region,
        IRouteResolver resolver,
        RegionControlProvider controlProvider)
        : base(logger, dispatcher, region, resolver, controlProvider)
    {
    }

    /// <inheritdoc/>
    protected override FrameworkElement? SelectedItem
    {
        get => Control?.SelectedItem as FrameworkElement;
        set
        {
            if (Control is not null)
            {
                Control.SelectedItem = (SelectorBarItem)value!;
            }
        }
    }

    /// <inheritdoc/>
    protected override IEnumerable<FrameworkElement> Items
    {
        get
        {
            if (Logger.IsEnabled(LogLevel.Trace))
            {
                Logger.LogTraceMessage($"{nameof(Items)}: {Control?.Items.Count}");
            }
            return Control?.Items.OfType<FrameworkElement>() ?? Array.Empty<FrameworkElement>();
        }
    }

    /// <inheritdoc/>
    protected override Action? AttachSelectionChanged(Action<FrameworkElement, FrameworkElement?> selectionChanged)
    {
        var control = Control;
        if (control is null)
        {
            if (Logger.IsEnabled(LogLevel.Warning))
            {
                Logger.LogWarningMessage($"Unable to attach selection changed handler as Control is null");
            }
            return default;
        }

        TypedEventHandler<SelectorBar, SelectorBarSelectionChangedEventArgs> handler =
            (sb, args) =>
            {
                selectionChanged(sb, sb.SelectedItem);
            };

        control.SelectionChanged += handler;
        return () => control.SelectionChanged -= handler;
    }
}