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feat: add keyboard navigation to NavMenu

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This commit is contained in:
SignorParabellaux
2025-05-31 22:28:22 +03:00
parent 87b971654a
commit f1c8d7a542
3 changed files with 380 additions and 37 deletions
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195
src/Ursa/Controls/NavMenu/NavMenu.cs
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@@ -1,6 +1,7 @@
using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.Metadata;
using Avalonia.Controls.Presenters;
using Avalonia.Controls.Primitives;
using Avalonia.Controls.Templates;
using Avalonia.Data;
@@ -8,13 +9,17 @@ using Avalonia.Input;
using Avalonia.Interactivity;
using Avalonia.LogicalTree;
using Avalonia.Metadata;
using Avalonia.VisualTree;
using Irihi.Avalonia.Shared.Helpers;
namespace Ursa.Controls;
[TemplatePart(PART_ItemsPresenter, typeof(ItemsPresenter))]
[PseudoClasses(PC_HorizontalCollapsed)]
public class NavMenu : ItemsControl
public class NavMenu : ItemsControl, ICustomKeyboardNavigation
{
public const string PART_ItemsPresenter = "PART_ItemsPresenter";
public const string PC_HorizontalCollapsed = ":horizontal-collapsed";
public static readonly StyledProperty<object?> SelectedItemProperty = AvaloniaProperty.Register<NavMenu, object?>(
@@ -69,7 +74,9 @@ public class NavMenu : ItemsControl
public static readonly RoutedEvent<SelectionChangedEventArgs> SelectionChangedEvent =
RoutedEvent.Register<NavMenu, SelectionChangedEventArgs>(nameof(SelectionChanged), RoutingStrategies.Bubble);
private ItemsPresenter? _itemsPresenter = null;
private bool _isSelectionFromUI = false;
private bool _isNavigatingMenu = false;
static NavMenu()
{
@@ -193,12 +200,34 @@ public class NavMenu : ItemsControl
return new NavMenuItem();
}
protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
{
base.OnApplyTemplate(e);
_itemsPresenter = e.NameScope.Find<ItemsPresenter>(PART_ItemsPresenter);
if (_itemsPresenter is not null)
KeyboardNavigation.SetTabNavigation(_itemsPresenter, KeyboardNavigationMode.Once);
}
protected override void OnLoaded(RoutedEventArgs e)
{
base.OnLoaded(e);
TryToSelectItem(SelectedItem);
}
protected override void OnKeyDown(KeyEventArgs e)
{
if (e.Handled) return;
var source = GetContainerFromEventSource(e.Source);
if (GetNextItem(source, e.Key) is { } target)
{
if (e.Key is Key.Up or Key.Down && source is { Level: 1 } firstLevelSource)
firstLevelSource.CloseAllOpenPopups();
e.Handled = target.Focus(NavigationMethod.Directional);
}
}
/// <summary>
/// this implementation only works in the case that only leaf menu item is allowed to select. It will be changed if we
/// introduce parent level selection in the future.
@@ -269,6 +298,96 @@ public class NavMenu : ItemsControl
item.ClearSelection();
}
(bool handled, IInputElement? next) ICustomKeyboardNavigation.GetNext(IInputElement element, NavigationDirection direction)
{
if (direction is not NavigationDirection.Next and not NavigationDirection.Previous ||
_isNavigatingMenu ||
_itemsPresenter is null) return (false, null);
var visual = element as Visual;
if (!_itemsPresenter.IsVisualAncestorOf(visual))
{
_isNavigatingMenu = true;
var next = KeyboardNavigationHandler.GetNext(element, direction);
_isNavigatingMenu = false;
if (_itemsPresenter.IsVisualAncestorOf(next as Visual))
{
var target = IsHorizontalCollapsed
? GetRootMenuItem(GetContainerForItem(SelectedItem))
: GetUncollapsedOrTopmostMenuItem(GetContainerForItem(SelectedItem));
target ??= ContainerFromIndex(this, 0);
return (target is not null, target);
}
}
else
{
_isNavigatingMenu = true;
var next = KeyboardNavigationHandler.GetNext(_itemsPresenter, direction);
_isNavigatingMenu = false;
if (element is NavMenuItem { Level: 1 } firstLevelItem) firstLevelItem.CloseAllOpenPopups();
return (true, next);
}
return (false, null);
}
private NavMenuItem? GetNextItem(NavMenuItem? current, Key key, bool skipChildren = false)
{
if (current?.Parent is not ItemsControl parent) return null;
var index = IndexFromContainer(parent, current);
return key switch
{
Key.Up => NavigateUp(),
Key.Down => NavigateDown(),
Key.Right when !IsHorizontalCollapsed => NavigateDown(),
Key.Left or Key.Escape => parent as NavMenuItem,
Key.Right or Key.Enter => FirstChild(current),
_ => null
};
NavMenuItem? NavigateUp()
{
if (FindSibling(parent, index - 1, -1) is { } previous)
return !IsHorizontalCollapsed && !previous.IsVerticalCollapsed && previous.ItemCount > 0
? LastChild(previous)
: previous;
return IsHorizontalCollapsed ? LastChild(parent) : parent as NavMenuItem;
}
NavMenuItem? NavigateDown()
{
if (!skipChildren &&
!IsHorizontalCollapsed &&
!current.IsVerticalCollapsed &&
current.ItemCount > 0 &&
FirstChild(current) is { } firstChild) return firstChild;
if (FindSibling(parent, index + 1, 1) is { } next) return next;
if (IsHorizontalCollapsed) return FirstChild(parent);
return GetNextItem(parent as NavMenuItem, key, true);
}
static NavMenuItem? FirstChild(ItemsControl control) => FindSibling(control, 0, 1);
static NavMenuItem? LastChild(ItemsControl control) => FindSibling(control, control.ItemCount - 1, -1);
static NavMenuItem? FindSibling(ItemsControl control, int start, int step)
{
for (var i = start; i >= 0 && i < control.ItemCount; i += step)
if (ContainerFromIndex(control, i) is { IsEnabled: true, IsSeparator: false } item) return item;
return null;
}
}
private bool TryToSelectItem(object? item)
{
if (item is null) return false;
@@ -293,4 +412,78 @@ public class NavMenu : ItemsControl
foreach (var leaf in leafs) yield return leaf;
}
}
public NavMenuItem? GetContainerForItem(object? item)
{
if (item == null) return null;
return GetContainerForItem(this, item);
static NavMenuItem? GetContainerForItem(ItemsControl control, object item)
{
if (ContainerFromItem(control, item) is NavMenuItem container) return container;
var children = GetRealizedContainers(control);
foreach (var child in children)
if (GetContainerForItem(child, item) is { } childContainer) return childContainer;
return null;
}
}
private NavMenuItem? GetContainerFromEventSource(object? eventSource)
{
if (eventSource is not Visual visual) return null;
return visual.GetSelfAndVisualAncestors()
.OfType<NavMenuItem>()
.FirstOrDefault(i => i.RootMenu == this);
}
private static NavMenuItem? ContainerFromIndex(ItemsControl itemsControl, int index) =>
itemsControl is NavMenuItem navMenuItem
? navMenuItem.CollapsedAwareContainerFromIndex(index)
: (NavMenuItem?)itemsControl.ContainerFromIndex(index);
private static NavMenuItem? ContainerFromItem(ItemsControl itemsControl, object item) =>
itemsControl is NavMenuItem navMenuItem
? navMenuItem.CollapsedAwareContainerFromItem(item)
: (NavMenuItem?)itemsControl.ContainerFromItem(item);
private static int IndexFromContainer(ItemsControl itemsControl, NavMenuItem container) =>
itemsControl is NavMenuItem navMenuItem
? navMenuItem.CollapsedAwareIndexFromContainer(container)
: itemsControl.IndexFromContainer(container);
private static IEnumerable<NavMenuItem> GetRealizedContainers(ItemsControl itemsControl)
{
var realizedContainers = itemsControl is NavMenuItem navMenuItem
? navMenuItem.CollapsedAwareRealizedContainers()
: itemsControl.GetRealizedContainers();
return realizedContainers.OfType<NavMenuItem>();
}
private static NavMenuItem? GetRootMenuItem(NavMenuItem? item)
{
if (item is null) return null;
return item.GetSelfAndLogicalAncestors()
.OfType<NavMenuItem>()
.FirstOrDefault(i => i.Level == 1);
}
private static NavMenuItem? GetUncollapsedOrTopmostMenuItem(NavMenuItem? item)
{
NavMenuItem? result = null;
while (item is not null)
{
var currentParent = item.Parent as NavMenuItem;
result ??= currentParent?.IsVerticalCollapsed is false ? item : null;
if (item.Level == 1) return result ?? item;
item = currentParent;
}
return null;
}
}