[iOS, Mac] Fix for CollectionView not triggering Scrolled event when grouped and groups are empty

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

@@ -29,8 +29,10 @@ public override void Scrolled(UIScrollView scrollView)
 		{
 			var (visibleItems, firstVisibleItemIndex, centerItemIndex, lastVisibleItemIndex) = GetVisibleItemsIndex();
 
-			if (!visibleItems)
+			if (!visibleItems && !HasHeaderOrFooter())
+			{
 				return;
+			}
 
 			var contentInset = scrollView.ContentInset;
 			var contentOffsetX = scrollView.ContentOffset.X + contentInset.Left;
@@ -147,6 +149,37 @@ protected virtual (bool VisibleItems, int First, int Center, int Last) GetVisibl
 			return (VisibleItems, firstVisibleItemIndex, centerItemIndex, lastVisibleItemIndex);
 		}
 
+		bool HasHeaderOrFooter()
+		{
+			var viewController = ViewController;
+
+			if (viewController?.ItemsView is null)
+			{
+				return false;
+			}
+
+			// Check for structured headers/footers
+			if (viewController.ItemsView is StructuredItemsView structuredItemsView)
+			{
+				if (structuredItemsView.Header is not null || structuredItemsView.HeaderTemplate is not null ||
+					structuredItemsView.Footer is not null || structuredItemsView.FooterTemplate is not null)
+				{
+					return true;
+				}
+			}
+
+			// Check for group headers/footers
+			if (viewController.ItemsView is GroupableItemsView groupableItemsView && groupableItemsView.IsGrouped)
+			{
+				if (groupableItemsView.GroupHeaderTemplate is not null || groupableItemsView.GroupFooterTemplate is not null)
+				{
+					return true;
+				}
+			}
+
+			return false;
+		}
+
 		static int GetItemIndex(NSIndexPath indexPath, IItemsViewSource itemSource)
 		{
 			int index = (int)indexPath.Item;

src/Controls/src/Core/Handlers/Items2/iOS/ItemsViewDelegator2.cs

@@ -30,8 +30,10 @@ public override void Scrolled(UIScrollView scrollView)
 		{
 			var (visibleItems, firstVisibleItemIndex, centerItemIndex, lastVisibleItemIndex) = GetVisibleItemsIndex();
 
-			if (!visibleItems)
+			if (!visibleItems && !HasHeaderOrFooter())
+			{
 				return;
+			}
 
 			var contentInset = scrollView.ContentInset;
 			var contentOffsetX = scrollView.ContentOffset.X + contentInset.Left;
@@ -148,6 +150,37 @@ protected virtual (bool VisibleItems, int First, int Center, int Last) GetVisibl
 			return (VisibleItems, firstVisibleItemIndex, centerItemIndex, lastVisibleItemIndex);
 		}
 
+		bool HasHeaderOrFooter()
+		{
+			var viewController = ViewController;
+
+			if (viewController?.ItemsView is null)
+			{
+				return false;
+			}
+
+			// Check for structured headers/footers (overall CollectionView header/footer)
+			if (viewController.ItemsView is StructuredItemsView structuredItemsView)
+			{
+				if (structuredItemsView.Header is not null || structuredItemsView.HeaderTemplate is not null ||
+					structuredItemsView.Footer is not null || structuredItemsView.FooterTemplate is not null)
+				{
+					return true;
+				}
+			}
+
+			// Check for group headers/footers (grouped CollectionView)
+			if (viewController.ItemsView is GroupableItemsView groupableItemsView && groupableItemsView.IsGrouped)
+			{
+				if (groupableItemsView.GroupHeaderTemplate is not null || groupableItemsView.GroupFooterTemplate is not null)
+				{
+					return true;
+				}
+			}
+
+			return false;
+		}
+
 		static int GetItemIndex(NSIndexPath indexPath, IItemsViewSource itemSource)
 		{
 			int index = (int)indexPath.Item;

src/Controls/tests/TestCases.HostApp/Issues/Issue30249.cs

@@ -0,0 +1,83 @@
+using System.Collections.ObjectModel;
+
+namespace Controls.TestCases.HostApp.Issues;
+
+[Issue(IssueTracker.Github, 30249, "Grouped CollectionView does not trigger the Scrolled event for empty groups", PlatformAffected.iOS)]
+public class Issue30249 : ContentPage
+{
+	CollectionView collectionViewWithEmptyGroups;
+	ObservableCollection<Issue30249Group> groupedItems = new ObservableCollection<Issue30249Group>();
+	Label scrolledEventStatusLabel;
+
+	public Issue30249()
+	{
+		Label descriptionLabel = new Label
+		{
+			Text = "Verify CollectionView Scrolled event is triggered for empty groups",
+			Margin = new Thickness(10)
+		};
+
+		scrolledEventStatusLabel = new Label
+		{
+			AutomationId = "ScrolledEventStatusLabel",
+			Text = "Failure",
+			Margin = new Thickness(10)
+		};
+
+		collectionViewWithEmptyGroups = new CollectionView
+		{
+			AutomationId = "CollectionViewWithEmptyGroups",
+			IsGrouped = true
+		};
+		collectionViewWithEmptyGroups.Scrolled += CollectionView_Scrolled;
+
+		collectionViewWithEmptyGroups.GroupHeaderTemplate = new DataTemplate(() =>
+		{
+			Label label = new Label
+			{
+				Padding = new Thickness(10),
+			};
+
+			label.SetBinding(Label.TextProperty, "Title");
+			return label;
+		});
+
+		for (int group = 0; group < 20; group++)
+		{
+			groupedItems.Add(new Issue30249Group($"Group {group}", new List<string>()));
+		}
+
+		collectionViewWithEmptyGroups.ItemsSource = groupedItems;
+
+		Grid grid = new Grid
+		{
+			RowDefinitions =
+			{
+				new RowDefinition { Height = GridLength.Auto },
+				new RowDefinition { Height = GridLength.Auto },
+				new RowDefinition { Height = GridLength.Star }
+			}
+		};
+
+		grid.Add(descriptionLabel, 0, 0);
+		grid.Add(scrolledEventStatusLabel, 0, 1);
+		grid.Add(collectionViewWithEmptyGroups, 0, 2);
+
+		Content = grid;
+	}
+
+	private void CollectionView_Scrolled(object sender, ItemsViewScrolledEventArgs e)
+	{
+		scrolledEventStatusLabel.Text = "Success";
+	}
+}
+
+public class Issue30249Group : List<string>
+{
+	public string Title { get; set; }
+
+	public Issue30249Group(string title, List<string> items) : base(items)
+	{
+		Title = title;
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue30249.cs

@@ -0,0 +1,25 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue30249 : _IssuesUITest
+{
+	public Issue30249(TestDevice device) : base(device)
+	{
+	}
+
+	public override string Issue => "Grouped CollectionView does not trigger the Scrolled event for empty groups";
+
+	[Test]
+	[Category(UITestCategories.CollectionView)]
+	public void VerifyScrolledEventForEmptyGroups()
+	{
+		App.WaitForElement("CollectionViewWithEmptyGroups");
+		App.ScrollDown("CollectionViewWithEmptyGroups", ScrollStrategy.Gesture, 0.2, 500);
+
+		var scrolledEventStatus = App.FindElement("ScrolledEventStatusLabel").GetText();
+		Assert.That(scrolledEventStatus, Is.EqualTo("Success"));
+	}
+}