[Catalyst] Fixed the CanMixGroups Set to False Still Allows Reordering Between Groups in CollectionView (#28623)

* Fixed the CanMixGroups Set to False Still Allows Reordering Between Groups in CollectionView

* Committed the test case and sample

* Committed the pending snap

Author: Ahamed-Ali

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

@@ -21,6 +21,11 @@ public ReorderableItemsViewController(TItemsView reorderableItemsView, ItemsView
 			// For some reason it only seemed to work when the CollectionView was inside the Flyout section of a FlyoutPage.
 			// The UILongPressGestureRecognizer is simple enough to set up so let's just add our own.
 			InstallsStandardGestureForInteractiveMovement = false;
+#if MACCATALYST
+			// On Mac Catalyst, the default normal press and drag interactions occur, causing the CanMixGroups = false logic to not work. 
+			// Since all reordering logic is handled exclusively by UILongPressGestureRecognizer, we can set DragInteractionEnabled to false, ensuring that only the long press gesture is used.
+			CollectionView.DragInteractionEnabled = false;
+#endif
 		}
 
 		public override bool CanMoveItem(UICollectionView collectionView, NSIndexPath indexPath)

src/Controls/src/Core/Handlers/Items2/iOS/ReorderableItemsViewController2.cs

@@ -21,6 +21,11 @@ public ReorderableItemsViewController2(TItemsView reorderableItemsView, UICollec
 			// For some reason it only seemed to work when the CollectionView was inside the Flyout section of a FlyoutPage.
 			// The UILongPressGestureRecognizer is simple enough to set up so let's just add our own.
 			InstallsStandardGestureForInteractiveMovement = false;
+#if MACCATALYST
+			// On Mac Catalyst, the default normal press and drag interactions occur, causing the CanMixGroups = false logic to not work. 
+			// Since all reordering logic is handled exclusively by UILongPressGestureRecognizer, we can set DragInteractionEnabled to false, ensuring that only the long press gesture is used.
+			CollectionView.DragInteractionEnabled = false;
+#endif
 		}
 
 		public override bool CanMoveItem(UICollectionView collectionView, NSIndexPath indexPath)

src/Controls/tests/TestCases.Android.Tests/snapshots/android/ReorderBetweenGroupsShouldNotOccurWhenCanMixGroupsIsFalse.png

@@ -0,0 +1,33 @@
+<?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.Issue28530">
+
+    <VerticalStackLayout Padding="10">
+        <CollectionView
+            ItemsSource="{Binding GroupedItems}"
+            IsGrouped="true"
+            CanReorderItems="true"
+            CanMixGroups="false"
+            AutomationId="CollectionViewControl">
+            <CollectionView.GroupHeaderTemplate>
+                <DataTemplate>
+                    <Label Text="{Binding GroupHeaderName}"
+                           FontAttributes="Bold"
+                           FontSize="14"
+                           Padding="5"/>
+                </DataTemplate>
+            </CollectionView.GroupHeaderTemplate>
+            <CollectionView.ItemTemplate>
+                <DataTemplate>
+                    <Label Text="{Binding Name}"
+                           AutomationId="{Binding .}"
+                           FontSize="12"
+                           Padding="5"/>
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </CollectionView>
+    </VerticalStackLayout>
+
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue28530.xaml

@@ -0,0 +1,56 @@
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+
+namespace Maui.Controls.Sample.Issues;
+[Issue(IssueTracker.Github, 28530, "[Catalyst] CanMixGroups Set to False Still Allows Reordering Between Groups in CollectionView", PlatformAffected.macOS)]
+public partial class Issue28530 : ContentPage
+{
+	public Issue28530()
+	{
+		InitializeComponent();
+		BindingContext = new Issue28530CollectionViewViewModel();
+	}
+}
+
+public class Issue28530CollectionViewViewModel : INotifyPropertyChanged
+{
+	public ObservableCollection<Issue28530GroupedItem> GroupedItems { get; set; }
+	public event PropertyChangedEventHandler PropertyChanged;
+
+	public Issue28530CollectionViewViewModel()
+	{
+		GroupedItems = new ObservableCollection<Issue28530GroupedItem>
+			{
+				new Issue28530GroupedItem("Group 1")
+				{
+					new Issue28530Item { Name = "Item 1" },
+					new Issue28530Item { Name = "Item 2" }
+				},
+				new Issue28530GroupedItem("Group 2")
+				{
+					new Issue28530Item { Name = "Item 3" },
+					new Issue28530Item { Name = "Item 4" }
+				}
+			};
+	}
+
+	protected void OnPropertyChanged(string propertyName)
+	{
+		PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+	}
+}
+
+public class Issue28530GroupedItem : ObservableCollection<Issue28530Item>
+{
+	public string GroupHeaderName { get; set; }
+
+	public Issue28530GroupedItem(string groupHeaderName)
+	{
+		GroupHeaderName = groupHeaderName;
+	}
+}
+
+public class Issue28530Item
+{
+	public string Name { get; set; }
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue28530.xaml.cs

@@ -0,0 +1,23 @@
+#if TEST_FAILS_ON_WINDOWS
+// https://github.com/dotnet/maui/issues/13027 In windows, .NET MAUI CollectionView does not reorder when grouped
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+public class Issue28530 : _IssuesUITest
+{
+	public Issue28530(TestDevice device) : base(device) { }
+
+	public override string Issue => "[Catalyst] CanMixGroups Set to False Still Allows Reordering Between Groups in CollectionView";
+
+	[Test]
+	[Category(UITestCategories.CollectionView)]
+	public void ReorderBetweenGroupsShouldNotOccurWhenCanMixGroupsIsFalse()
+	{
+		App.WaitForElement("CollectionViewControl");
+		App.DragAndDrop("Item 2", "Item 3");
+		VerifyScreenshot();
+	}
+}
+#endif