[Accessibility] Add Accessibility Traits to CollectionView items on iOS/Catalyst

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

@@ -5,6 +5,7 @@
 using Foundation;
 using ObjCRuntime;
 using UIKit;
+using Microsoft.Maui.Controls.Platform;
 
 namespace Microsoft.Maui.Controls.Handlers.Items
 {
@@ -149,6 +150,7 @@ internal void UpdateSelectionMode()
 			}
 
 			UpdatePlatformSelection();
+			CollectionView.UpdateAccessibilityTraits(ItemsView);
 		}
 
 		void SynchronizePlatformSelectionWithSelectedItems()

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

@@ -6,6 +6,7 @@
 using Microsoft.Maui.Controls.Internals;
 using Microsoft.Maui.Graphics;
 using UIKit;
+using Microsoft.Maui.Controls.Platform;
 
 namespace Microsoft.Maui.Controls.Handlers.Items
 {
@@ -202,6 +203,7 @@ public void Bind(DataTemplate template, object bindingContext, ItemsView itemsVi
 			}
 
 			CurrentTemplate = itemTemplate;
+			this.UpdateAccessibilityTraits(itemsView);
 		}
 
 		void SetRenderer(IPlatformViewHandler renderer)

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

@@ -5,6 +5,7 @@
 using Foundation;
 using ObjCRuntime;
 using UIKit;
+using Microsoft.Maui.Controls.Platform;
 
 namespace Microsoft.Maui.Controls.Handlers.Items2
 {
@@ -149,6 +150,7 @@ internal void UpdateSelectionMode()
 			}
 
 			UpdatePlatformSelection();
+			CollectionView.UpdateAccessibilityTraits(ItemsView);
 		}
 
 		void SynchronizePlatformSelectionWithSelectedItems()

src/Controls/src/Core/Handlers/Items2/iOS/TemplatedCell2.cs

@@ -145,6 +145,8 @@ void BindVirtualView(View virtualView, object bindingContext, ItemsView itemsVie
 			{
 				view.SetValueFromRenderer(BindableObject.BindingContextProperty, bindingContext);
 			}
+
+			this.UpdateAccessibilityTraits(itemsView);
 		}
 
 		bool IsUsingVSMForSelectionColor(View view)

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

@@ -0,0 +1,43 @@
+using UIKit;
+
+namespace Microsoft.Maui.Controls.Platform;
+
+internal static class AcessibilityExtensions
+{
+	internal static void UpdateAccessibilityTraits(this UICollectionView collectionView, SelectableItemsView itemsView)
+	{
+		foreach (var subview in collectionView.Subviews)
+		{
+			if (subview is UICollectionViewCell cell)
+			{
+				cell.UpdateAccessibilityTraits(itemsView);
+			}
+		}
+	}
+
+	internal static void UpdateAccessibilityTraits(this UICollectionViewCell cell, ItemsView itemsView)
+	{
+		var selectionMode = (itemsView as CollectionView)?.SelectionMode;
+		if (cell.ContentView is not null
+			&& cell.ContentView.Subviews.Length > 0
+			&& selectionMode is not null)
+		{
+			var firstChild = cell.ContentView.Subviews[0];
+
+			// if the first child is a control, changing the accessibility traits from an entry to a button could be confusing.
+			if (firstChild is UIControl)
+			{
+				return;
+			}
+
+			if (selectionMode != SelectionMode.None)
+			{
+				firstChild.AccessibilityTraits |= UIAccessibilityTrait.Button;
+			}
+			else
+			{
+				firstChild.AccessibilityTraits &= ~UIAccessibilityTrait.Button;
+			}
+		}
+	}
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue26817.xaml

@@ -0,0 +1,72 @@
+<?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.Issue26817">
+    <VerticalStackLayout>
+      <Label Text="Border" Padding="0,10,10,10"/>
+      <local:CollectionView2 SelectionMode="Single" x:Name="border">
+         <CollectionView.ItemsSource>
+               <x:Array Type="{x:Type x:String}">
+                  <x:String>Item 1</x:String>
+                  <x:String>Item 2</x:String>
+               </x:Array>
+         </CollectionView.ItemsSource>
+         <CollectionView.ItemTemplate>
+               <DataTemplate>
+                  <Border BackgroundColor="LightGray" Padding="10" Margin="5" SemanticProperties.Description="{Binding}">
+                     <VerticalStackLayout>
+                        <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                        <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" />
+                        <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                     </VerticalStackLayout>
+                  </Border>
+               </DataTemplate>
+         </CollectionView.ItemTemplate>
+      </local:CollectionView2>
+
+      <Label Text="VerticalStackLayout" Padding="0,10,10,10"/>
+      <local:CollectionView2 SelectionMode="Single" x:Name="vsl">
+         <CollectionView.ItemsSource>
+               <x:Array Type="{x:Type x:String}">
+                  <x:String>Item 1</x:String>
+                  <x:String>Item 2</x:String>
+               </x:Array>
+         </CollectionView.ItemsSource>
+         <CollectionView.ItemTemplate>
+               <DataTemplate>
+                  <VerticalStackLayout BackgroundColor="LightBlue" Padding="10" Margin="5"  SemanticProperties.Description="{Binding}">
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" />
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                  </VerticalStackLayout>
+               </DataTemplate>
+         </CollectionView.ItemTemplate>
+      </local:CollectionView2>
+
+      <Label Text="Grid" Padding="0,10,10,10"/>
+      <local:CollectionView2 SelectionMode="Single" x:Name="grid">
+         <CollectionView.ItemsSource>
+               <x:Array Type="{x:Type x:String}">
+                  <x:String>Item 1</x:String>
+                  <x:String>Item 2</x:String>
+               </x:Array>
+         </CollectionView.ItemsSource>
+         <CollectionView.ItemTemplate>
+               <DataTemplate>
+                  <Grid BackgroundColor="LightGreen" Padding="10" Margin="5"  SemanticProperties.Description="{Binding}" RowDefinitions="*,*,*">
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" Grid.Row="0"/>
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" Grid.Row="1"/>
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" Grid.Row="2"/>
+                  </Grid>
+               </DataTemplate>
+         </CollectionView.ItemTemplate>
+      </local:CollectionView2>
+
+      <Button Text="Toggle SelectionMode" Clicked="Button_Clicked" AutomationId="ToggleSelectionModeButton" />
+      <Label x:Name="selectionLabel" />
+      <Label Text="Border Item is Button?" x:Name="Label1" />
+      <Label Text="VerticalStackLayout Item is Button?" x:Name="Label2" />
+      <Label Text="Grid Item is Button?" x:Name="Label3" />
+    </VerticalStackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue26817.xaml.cs

@@ -0,0 +1,56 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 26817, "CollectionViewHandler2 assigns Accessibility Traits with SelectionMode correctly", PlatformAffected.macOS)]
+	public partial class Issue26817 : ContentPage
+	{
+		public Issue26817()
+		{
+			InitializeComponent();
+		}
+
+		int toggleCount;
+
+		private void Button_Clicked(object sender, EventArgs e)
+		{
+			var selectionMode = toggleCount switch
+			{
+				0 => SelectionMode.None,
+				1 => SelectionMode.Single,
+				2 => SelectionMode.Multiple,
+				_ => throw new NotImplementedException(),
+			};
+
+			border.SelectionMode = selectionMode;
+			vsl.SelectionMode = selectionMode;
+			grid.SelectionMode = selectionMode;
+			CheckAccessibilityTraits(border, Label1, "Border:");
+			CheckAccessibilityTraits(vsl, Label2, "VSL:");
+			CheckAccessibilityTraits(grid, Label3, "Grid:");
+
+			selectionLabel.Text = "selectionMode: " + selectionMode;
+
+			toggleCount = (toggleCount + 1) % 3;
+		}
+
+		public void CheckAccessibilityTraits(CollectionView collectionView, Label label, string prefix)
+		{
+#if IOS || MACCATALYST
+			if (collectionView.Handler?.PlatformView is UIKit.UIView collectionViewWrapper)
+			{
+				if (collectionViewWrapper.Subviews.Length == 0 || collectionViewWrapper.Subviews[0] is not UIKit.UIView cv)
+					return;
+
+				foreach (var child in cv.Subviews)
+				{
+					if (child is UIKit.UICollectionViewCell cell && cell.ContentView.Subviews.FirstOrDefault() is UIKit.UIView firstChild)
+					{
+						bool isButton = (firstChild.AccessibilityTraits & UIKit.UIAccessibilityTrait.Button) == UIKit.UIAccessibilityTrait.Button;
+						label.Text = $"{prefix} Item is Button - {isButton}";
+						break;
+					}
+				}
+			}
+#endif
+		}
+	}
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue26817_2.xaml

@@ -0,0 +1,72 @@
+<?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.Issue26817_2">
+    <VerticalStackLayout>
+      <Label Text="Border" Padding="0,10,10,10"/>
+      <CollectionView SelectionMode="Single" x:Name="border">
+         <CollectionView.ItemsSource>
+               <x:Array Type="{x:Type x:String}">
+                  <x:String>Item 1</x:String>
+                  <x:String>Item 2</x:String>
+               </x:Array>
+         </CollectionView.ItemsSource>
+         <CollectionView.ItemTemplate>
+               <DataTemplate>
+                  <Border BackgroundColor="LightGray" Padding="10" Margin="5" SemanticProperties.Description="{Binding}">
+                     <VerticalStackLayout>
+                        <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                        <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" />
+                        <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                     </VerticalStackLayout>
+                  </Border>
+               </DataTemplate>
+         </CollectionView.ItemTemplate>
+      </CollectionView>
+
+      <Label Text="VerticalStackLayout" Padding="0,10,10,10"/>
+      <CollectionView SelectionMode="Single" x:Name="vsl">
+         <CollectionView.ItemsSource>
+               <x:Array Type="{x:Type x:String}">
+                  <x:String>Item 1</x:String>
+                  <x:String>Item 2</x:String>
+               </x:Array>
+         </CollectionView.ItemsSource>
+         <CollectionView.ItemTemplate>
+               <DataTemplate>
+                  <VerticalStackLayout BackgroundColor="LightBlue" Padding="10" Margin="5"  SemanticProperties.Description="{Binding}">
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" />
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center"/>
+                  </VerticalStackLayout>
+               </DataTemplate>
+         </CollectionView.ItemTemplate>
+      </CollectionView>
+
+      <Label Text="Grid" Padding="0,10,10,10"/>
+      <CollectionView SelectionMode="Single" x:Name="grid">
+         <CollectionView.ItemsSource>
+               <x:Array Type="{x:Type x:String}">
+                  <x:String>Item 1</x:String>
+                  <x:String>Item 2</x:String>
+               </x:Array>
+         </CollectionView.ItemsSource>
+         <CollectionView.ItemTemplate>
+               <DataTemplate>
+                  <Grid BackgroundColor="LightGreen" Padding="10" Margin="5"  SemanticProperties.Description="{Binding}" RowDefinitions="*,*,*">
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" Grid.Row="0"/>
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" Grid.Row="1"/>
+                     <Label Text="{Binding}" HorizontalOptions="Center" VerticalOptions="Center" Grid.Row="2"/>
+                  </Grid>
+               </DataTemplate>
+         </CollectionView.ItemTemplate>
+      </CollectionView>
+
+      <Button Text="Toggle SelectionMode" Clicked="Button_Clicked" AutomationId="ToggleSelectionModeButton" />
+      <Label x:Name="selectionLabel" />
+      <Label Text="Border Item is Button?" x:Name="Label1" />
+      <Label Text="VerticalStackLayout Item is Button?" x:Name="Label2" />
+      <Label Text="Grid Item is Button?" x:Name="Label3" />
+    </VerticalStackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue26817_2.xaml.cs

@@ -0,0 +1,56 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 26817_2, "CollectionViewHandler assigns Accessibility Traits with SelectionMode correctly", PlatformAffected.macOS)]
+	public partial class Issue26817_2 : ContentPage
+	{
+		public Issue26817_2()
+		{
+			InitializeComponent();
+		}
+
+		int toggleCount;
+
+		private void Button_Clicked(object sender, EventArgs e)
+		{
+			var selectionMode = toggleCount switch
+			{
+				0 => SelectionMode.None,
+				1 => SelectionMode.Single,
+				2 => SelectionMode.Multiple,
+				_ => throw new NotImplementedException(),
+			};
+
+			border.SelectionMode = selectionMode;
+			vsl.SelectionMode = selectionMode;
+			grid.SelectionMode = selectionMode;
+			CheckAccessibilityTraits(border, Label1, "Border:");
+			CheckAccessibilityTraits(vsl, Label2, "VSL:");
+			CheckAccessibilityTraits(grid, Label3, "Grid:");
+
+			selectionLabel.Text = "selectionMode: " + selectionMode;
+
+			toggleCount = (toggleCount + 1) % 3;
+		}
+
+		public void CheckAccessibilityTraits(CollectionView collectionView, Label label, string prefix)
+		{
+#if IOS || MACCATALYST
+			if (collectionView.Handler?.PlatformView is UIKit.UIView collectionViewWrapper)
+			{
+				if (collectionViewWrapper.Subviews.Length == 0 || collectionViewWrapper.Subviews[0] is not UIKit.UIView cv)
+					return;
+
+				foreach (var child in cv.Subviews)
+				{
+					if (child is UIKit.UICollectionViewCell cell && cell.ContentView.Subviews.FirstOrDefault() is UIKit.UIView firstChild)
+					{
+						bool isButton = (firstChild.AccessibilityTraits & UIKit.UIAccessibilityTrait.Button) == UIKit.UIAccessibilityTrait.Button;
+						label.Text = $"{prefix} Item is Button - {isButton}";
+						break;
+					}
+				}
+			}
+#endif
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue26817.cs

@@ -0,0 +1,31 @@
+#if MACCATALYST || IOS
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue26817 : _IssuesUITest
+	{
+		public Issue26817(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "CollectionViewHandler2 assigns Accessibility Traits with SelectionMode correctly";
+
+		[Test]
+		[Category(UITestCategories.CollectionView)]
+		public void AccessibilityTraitsSetCorrectly()
+		{
+			App.WaitForElement("ToggleSelectionModeButton").Click();
+			VerifyScreenshot(TestContext.CurrentContext.Test.MethodName + "None");
+			App.WaitForElement("ToggleSelectionModeButton").Click();
+			VerifyScreenshot(TestContext.CurrentContext.Test.MethodName + "Single");
+			App.WaitForElement("ToggleSelectionModeButton").Click();
+			VerifyScreenshot(TestContext.CurrentContext.Test.MethodName + "Multiple");
+			App.WaitForElement("ToggleSelectionModeButton").Click();
+			VerifyScreenshot(TestContext.CurrentContext.Test.MethodName + "None");
+		}
+	}
+}
+#endif