Add Accessibility Selected for iOS CollectionView

src/Controls/src/Core/Handlers/Items/Android/SelectableViewHolder.cs

@@ -34,6 +34,7 @@ public bool IsSelected
 				SetSelectionStates(_isSelected);
 
 				ItemView.Activated = _isSelected;
+				ItemView.Selected = _isSelected;
 				OnSelectedChanged();
 			}
 		}

src/Controls/src/Core/Handlers/Items/iOS/SelectableItemsViewController.cs

@@ -45,6 +45,7 @@ internal void SelectItem(object selectedItem)
 				CollectionView.PerformBatchUpdates(null, _ =>
 				{
 					CollectionView.SelectItem(index, true, UICollectionViewScrollPosition.None);
+					CollectionView.CellForItem(index)?.UpdateSelectedAccessibility(true);
 				});
 			}
 		}
@@ -75,6 +76,8 @@ void FormsSelectItem(NSIndexPath indexPath)
 					ItemsView.SelectedItems.Add(GetItemAtIndex(indexPath));
 					break;
 			}
+
+			CollectionView.CellForItem(indexPath)?.UpdateSelectedAccessibility(true);
 		}
 
 		void FormsDeselectItem(NSIndexPath indexPath)
@@ -91,6 +94,8 @@ void FormsDeselectItem(NSIndexPath indexPath)
 					ItemsView.SelectedItems.Remove(GetItemAtIndex(indexPath));
 					break;
 			}
+
+			CollectionView.CellForItem(indexPath)?.UpdateSelectedAccessibility(false);
 		}
 
 		internal void UpdatePlatformSelection()
@@ -130,6 +135,10 @@ internal void UpdateSelectionMode()
 		{
 			var mode = ItemsView.SelectionMode;
 
+			// We want to make sure we clear the selection trait before we switch modes.
+			// If we do this after we switch modes, cells that are selected may not show up as selected anymore.
+			CollectionView.ClearSelectedAccessibilityTraits(CollectionView.GetIndexPathsForSelectedItems());
+
 			switch (mode)
 			{
 				case SelectionMode.None:

src/Controls/src/Core/Handlers/Items2/iOS/SelectableItemsViewController2.cs

@@ -45,6 +45,7 @@ internal void SelectItem(object selectedItem)
 				CollectionView.PerformBatchUpdates(null, _ =>
 				{
 					CollectionView.SelectItem(index, true, UICollectionViewScrollPosition.None);
+					CollectionView.CellForItem(index)?.UpdateSelectedAccessibility(true);
 				});
 			}
 		}
@@ -75,6 +76,8 @@ void FormsSelectItem(NSIndexPath indexPath)
 					ItemsView.SelectedItems.Add(GetItemAtIndex(indexPath));
 					break;
 			}
+
+			CollectionView.CellForItem(indexPath)?.UpdateSelectedAccessibility(true);
 		}
 
 		void FormsDeselectItem(NSIndexPath indexPath)
@@ -91,6 +94,8 @@ void FormsDeselectItem(NSIndexPath indexPath)
 					ItemsView.SelectedItems.Remove(GetItemAtIndex(indexPath));
 					break;
 			}
+
+			CollectionView.CellForItem(indexPath)?.UpdateSelectedAccessibility(false);
 		}
 
 		internal void UpdatePlatformSelection()
@@ -130,6 +135,10 @@ internal void UpdateSelectionMode()
 		{
 			var mode = ItemsView.SelectionMode;
 
+			// We want to make sure we clear the selection trait before we switch modes.
+			// If we do this after we switch modes, cells that are selected may not show up as selected anymore.
+			CollectionView.ClearSelectedAccessibilityTraits(CollectionView.GetIndexPathsForSelectedItems());
+
 			switch (mode)
 			{
 				case SelectionMode.None:

src/Controls/src/Core/Platform/iOS/Extensions/AcessibilityExtensions.cs

@@ -4,6 +4,46 @@ namespace Microsoft.Maui.Controls.Platform;
 
 internal static class AcessibilityExtensions
 {
+	internal static void UpdateSelectedAccessibility(this UICollectionViewCell cell, bool selected)
+	{
+		// Catalyst and iOS Simulators applies/removes the 'Selected' trait to the cell automatically.
+		// iOS Devices do not apply the 'Selected' trait automatically to the cell unless VoiceOver is on.
+		// On iOS, the 'Selected' trait needs to be applied to the first child of the cell for VoiceOver to announce it.
+#if IOS
+		if (cell.ContentView is not null && cell.ContentView.Subviews.Length > 0)
+		{
+			var firstChild = cell.ContentView.Subviews[0];
+
+			if (selected)
+			{
+				firstChild.AccessibilityTraits |= UIAccessibilityTrait.Selected;
+			}
+			else
+			{
+				firstChild.AccessibilityTraits &= ~UIAccessibilityTrait.Selected;
+			}
+		}
+#endif
+	}
+
+	internal static void ClearSelectedAccessibilityTraits(this UICollectionView collectionView, Foundation.NSIndexPath[] indices)
+	{
+		// Catalyst and iOS Simulators applies/removes the 'Selected' trait to the cell automatically.
+		// iOS Devices do not apply the 'Selected' trait automatically to the cell unless VoiceOver is on.
+		// On iOS, the 'Selected' trait needs to be applied to the first child of the cell for VoiceOver to announce it.
+#if IOS
+		foreach (var index in indices)
+		{
+			var cell = collectionView.CellForItem(index);
+			if (cell?.ContentView is not null && cell.ContentView.Subviews.Length > 0)
+			{
+				var firstChild = cell.ContentView.Subviews[0];
+				firstChild.AccessibilityTraits &= ~UIAccessibilityTrait.Selected;
+			}
+		}
+#endif
+	}
+
 	internal static void UpdateAccessibilityTraits(this UICollectionView collectionView, SelectableItemsView itemsView)
 	{
 		foreach (var subview in collectionView.Subviews)

src/Controls/tests/TestCases.HostApp/Issues/Issue21375.xaml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.Issue21375"
+             Title="Issue21375">
+    <VerticalStackLayout>
+        <CollectionView ItemsSource="{Binding Items}" SelectionMode="Single" x:Name="collectionView" AutomationId="collectionView" Background="LightBlue">
+            <CollectionView.ItemTemplate>
+                <DataTemplate>
+                    <StackLayout Padding="10" SemanticProperties.Description="{Binding Name}" HeightRequest="50">
+                        <Label Text="{Binding Name}" FontAttributes="Bold" FontSize="16"/>
+                        <Label Text="{Binding Description}" FontSize="14"/>
+                    </StackLayout>
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </CollectionView>
+        <Label Margin="0,10,0,0" Text="SelectionMode" />
+        <Button Text="None" Clicked="NoneSelectionMode" x:Name="noneButton" AutomationId="noneButton"/>
+        <Button Text="Single" Clicked="SingleSelectionMode" AutomationId="singleButton"/>
+        <Button Text="Multiple" Clicked="MultipleSelectionMode" AutomationId="multipleButton" />
+        <Button Text="Calculate" Clicked="Calculate" x:Name="calculateButton" AutomationId="calculateButton"/>
+        <Editor x:Name="Output" HeightRequest="400"/>
+    </VerticalStackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue21375.xaml.cs

@@ -0,0 +1,104 @@
+using System.Collections.ObjectModel;
+using System.Text;
+
+#if ANDROID
+using AndroidX.RecyclerView.Widget;
+#endif
+
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 21375, "Selected CollectionView item is not announced", PlatformAffected.iOS & PlatformAffected.macOS & PlatformAffected.Android)]
+public partial class Issue21375 : ContentPage
+{
+	public ObservableCollection<Item> Items { get; set; }
+
+	public Issue21375()
+	{
+		InitializeComponent();
+
+		Items = new ObservableCollection<Item>
+		{
+			new Item { Name = "Item 1", Description = "Description for item 1" },
+			new Item { Name = "Item 2", Description = "Description for item 2" },
+			new Item { Name = "Item 3", Description = "Description for item 3" },
+			new Item { Name = "Item 4", Description = "Description for item 4" },
+			new Item { Name = "Item 5", Description = "Description for item 5" }
+		};
+
+		BindingContext = this;
+	}
+
+	void NoneSelectionMode(object sender, EventArgs e)
+	{
+		collectionView.SelectionMode = SelectionMode.None;
+	}
+
+	void SingleSelectionMode(object sender, EventArgs e)
+	{
+		collectionView.SelectionMode = SelectionMode.Single;
+	}
+
+	void MultipleSelectionMode(object sender, EventArgs e)
+	{
+		collectionView.SelectionMode = SelectionMode.Multiple;
+	}
+
+	void Calculate(object sender, EventArgs e)
+	{
+		var sb = new StringBuilder();
+#if IOS || MACCATALYST
+		if (collectionView.Handler?.PlatformView is UIKit.UIView vc
+			&& vc.Subviews is UIKit.UIView[] subviews && subviews.Length > 0
+			&& subviews[0] is UIKit.UICollectionView uiCollectionView)
+		{
+			for (int i = 0; i < uiCollectionView.VisibleCells.Length; i++)
+			{
+				var cell = uiCollectionView.VisibleCells[i];
+				sb.AppendLine($"Item{i} Cell: {cell.AccessibilityTraits}");
+				if (cell.ContentView is not null && cell.ContentView.Subviews.Length > 0)
+				{
+					var firstChild = cell.ContentView.Subviews[0];
+					sb.AppendLine($"Item{i} FirstChild: {firstChild.AccessibilityTraits}");
+				}
+			}
+		}
+#elif ANDROID
+		var plat = collectionView.Handler?.PlatformView;
+		if (plat is RecyclerView recyclerView)
+		{
+			var adapter = recyclerView.GetAdapter();
+			var layoutManager = recyclerView.GetLayoutManager();
+			var childCount = layoutManager.ChildCount;
+			for (int i = 0; i < childCount; i++)
+			{
+				var viewHolder = recyclerView.GetChildAt(i);
+				if (viewHolder is null)
+					continue;
+
+				var position = recyclerView.GetChildAdapterPosition(viewHolder);
+				sb.AppendLine($"Item{position} Cell: {viewHolder.Selected}");
+			}
+		}
+#elif WINDOWS
+		var plat = collectionView.Handler?.PlatformView;
+		if (plat is Microsoft.UI.Xaml.Controls.ListView listView)
+		{
+			foreach (var item in listView.Items)
+			{
+				var container = listView.ContainerFromItem(item) as Microsoft.UI.Xaml.Controls.ListViewItem;
+				if (container != null)
+				{
+					sb.AppendLine($"Item: {item} IsSelected: {container.IsSelected}");
+				}
+			}
+		}
+#endif
+		Output.Text = sb.ToString();
+	}
+
+	public class Item
+	{
+		public string Name { get; set; }
+		public string Description { get; set; }
+	}
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue21375_2.xaml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             xmlns:local="clr-namespace:Maui.Controls.Sample"
+             x:Class="Maui.Controls.Sample.Issues.Issue21375_2">
+    <VerticalStackLayout>
+        <local:CollectionView2 ItemsSource="{Binding Items}" SelectionMode="Single" x:Name="collectionView" AutomationId="collectionView" Background="LightBlue">
+            <CollectionView.ItemTemplate>
+                <DataTemplate>
+                    <StackLayout Padding="10" SemanticProperties.Description="{Binding Name}" HeightRequest="50">
+                        <Label Text="{Binding Name}" FontAttributes="Bold" FontSize="16"/>
+                        <Label Text="{Binding Description}" FontSize="14"/>
+                    </StackLayout>
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </local:CollectionView2>
+        <Label Margin="0,10,0,0" Text="SelectionMode" />
+        <Button Text="None" Clicked="NoneSelectionMode" x:Name="noneButton" AutomationId="noneButton"/>
+        <Button Text="Single" Clicked="SingleSelectionMode" AutomationId="singleButton"/>
+        <Button Text="Multiple" Clicked="MultipleSelectionMode" AutomationId="multipleButton" />
+        <Button Text="Calculate" Clicked="Calculate" x:Name="calculateButton" AutomationId="calculateButton"/>
+        <Editor x:Name="Output" HeightRequest="400"/>
+    </VerticalStackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue21375_2.xaml.cs

@@ -0,0 +1,70 @@
+using System.Collections.ObjectModel;
+using System.Text;
+
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 21375_2, "Selected CollectionView2 item is not announced", PlatformAffected.iOS & PlatformAffected.macOS)]
+public partial class Issue21375_2 : ContentPage
+{
+	public ObservableCollection<Item> Items { get; set; }
+
+	public Issue21375_2()
+	{
+		InitializeComponent();
+
+		Items = new ObservableCollection<Item>
+		{
+			new Item { Name = "Item 1", Description = "Description for item 1" },
+			new Item { Name = "Item 2", Description = "Description for item 2" },
+			new Item { Name = "Item 3", Description = "Description for item 3" },
+			new Item { Name = "Item 4", Description = "Description for item 4" },
+			new Item { Name = "Item 5", Description = "Description for item 5" }
+		};
+
+		BindingContext = this;
+	}
+
+	void NoneSelectionMode(object sender, EventArgs e)
+	{
+		collectionView.SelectionMode = SelectionMode.None;
+	}
+
+	void SingleSelectionMode(object sender, EventArgs e)
+	{
+		collectionView.SelectionMode = SelectionMode.Single;
+	}
+
+	void MultipleSelectionMode(object sender, EventArgs e)
+	{
+		collectionView.SelectionMode = SelectionMode.Multiple;
+	}
+
+	void Calculate(object sender, EventArgs e)
+	{
+		var sb = new StringBuilder();
+#if IOS || MACCATALYST
+		if (collectionView.Handler?.PlatformView is UIKit.UIView vc
+			&& vc.Subviews is UIKit.UIView[] subviews && subviews.Length > 0
+			&& subviews[0] is UIKit.UICollectionView uiCollectionView)
+		{
+			for (int i = 0; i < uiCollectionView.VisibleCells.Length; i++)
+			{
+				var cell = uiCollectionView.VisibleCells[i];
+				sb.AppendLine($"Item{i} Cell: {cell.AccessibilityTraits}");
+				if (cell.ContentView is not null && cell.ContentView.Subviews.Length > 0)
+				{
+					var firstChild = cell.ContentView.Subviews[0];
+					sb.AppendLine($"Item{i} FirstChild: {firstChild.AccessibilityTraits}");
+				}
+			}
+		}
+#endif
+		Output.Text = sb.ToString();
+	}
+
+	public class Item
+	{
+		public string Name { get; set; }
+		public string Description { get; set; }
+	}
+}