[Android] Fix for CollectionView.EmptyView does not remeasure its height when the parent layout changes dynamically, causing incorrect sizing.

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

@@ -109,8 +109,37 @@ void UpdateEmptyViewSize(double width, double height)
 
 			if (adapter is EmptyViewAdapter emptyViewAdapter)
 			{
+				double tolerance = 0.001;
+				var widthChanged = Math.Abs(emptyViewAdapter.RecyclerViewWidth - width) > tolerance;
+				var heightChanged = Math.Abs(emptyViewAdapter.RecyclerViewHeight - height) > tolerance;
+
 				emptyViewAdapter.RecyclerViewWidth = width;
 				emptyViewAdapter.RecyclerViewHeight = height;
+
+				if (widthChanged || heightChanged)
+				{
+					// EmptyView position depends on whether the CollectionView has a header
+					var structuredItemsView = VirtualView as StructuredItemsView;
+					var hasHeader = (structuredItemsView?.Header ?? structuredItemsView?.HeaderTemplate) is not null;
+					var emptyViewPosition = hasHeader ? 1 : 0;
+
+					// Check if ViewHolder exists and is ready for immediate layout request
+					var viewHolder = PlatformView.FindViewHolderForAdapterPosition(emptyViewPosition);
+					if (viewHolder is not null)
+					{
+						// ViewHolder exists, request layout immediately to avoid frame delay
+						viewHolder.ItemView.RequestLayout();
+					}
+					else
+					{
+						// ViewHolder not created yet, defer layout request to next UI loop iteration
+						PlatformView.Post(() =>
+						{
+							var vh = PlatformView.FindViewHolderForAdapterPosition(emptyViewPosition);
+							vh?.ItemView.RequestLayout();
+						});
+					}
+				}
 			}
 		}
 	}

src/Controls/tests/TestCases.HostApp/Issues/Issue33324.cs

@@ -0,0 +1,171 @@
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 33324, "CollectionView.EmptyView does not remeasure its height when the parent layout changes dynamically", PlatformAffected.Android)]
+public class Issue33324 : ContentPage
+{
+	readonly Issue33324ViewModel _viewModel;
+
+	public Issue33324()
+	{
+		Title = "Issue 33324 - EmptyView Height";
+
+		_viewModel = new Issue33324ViewModel();
+		BindingContext = _viewModel;
+
+		var firstCollectionView = new CollectionView2
+		{
+			AutomationId = "FirstCollectionView",
+			HeightRequest = 380,
+			ItemTemplate = new DataTemplate(() =>
+			{
+				var label = new Label { Margin = new Thickness(10, 5) };
+				label.SetBinding(Label.TextProperty, ".");
+				return label;
+			})
+		};
+		firstCollectionView.SetBinding(CollectionView.ItemsSourceProperty, nameof(Issue33324ViewModel.MyItems));
+
+		var itemsContainer = new VerticalStackLayout();
+		itemsContainer.SetBinding(VisualElement.IsVisibleProperty, nameof(Issue33324ViewModel.HasItems));
+		itemsContainer.Children.Add(new Label
+		{
+			Text = "Items Loaded:",
+			FontAttributes = FontAttributes.Bold,
+			Margin = new Thickness(10, 0, 0, 0)
+		});
+		itemsContainer.Children.Add(firstCollectionView);
+
+		var loadButton = new Button
+		{
+			Text = "Load Items",
+			AutomationId = "LoadItemsButton",
+			Margin = new Thickness(10)
+		};
+		loadButton.SetBinding(Button.CommandProperty, nameof(Issue33324ViewModel.LoadItemsCommand));
+
+		var topContainer = new VerticalStackLayout();
+		topContainer.Children.Add(itemsContainer);
+		topContainer.Children.Add(loadButton);
+
+		var emptyViewLabel = new Label
+		{
+			Text = "No players available",
+			AutomationId = "EmptyViewLabel",
+			HorizontalOptions = LayoutOptions.Center,
+			VerticalOptions = LayoutOptions.Center,
+			FontSize = 18,
+			TextColor = Colors.Black
+		};
+
+		var emptyViewGrid = new Grid
+		{
+			AutomationId = "EmptyViewGrid"
+		};
+		emptyViewGrid.Children.Add(new BoxView
+		{
+			Color = Colors.Pink,
+			AutomationId = "EmptyViewBackground"
+		});
+		emptyViewGrid.Children.Add(emptyViewLabel);
+
+		var secondCollectionView = new CollectionView2
+		{
+			AutomationId = "SecondCollectionView",
+			EmptyView = emptyViewGrid
+		};
+		secondCollectionView.SetBinding(CollectionView.ItemsSourceProperty, nameof(Issue33324ViewModel.Players));
+
+		var mainGrid = new Grid
+		{
+			RowDefinitions =
+			{
+				new RowDefinition { Height = GridLength.Auto },
+				new RowDefinition { Height = GridLength.Star }
+			},
+			RowSpacing = 20
+		};
+
+		mainGrid.Add(topContainer, 0, 0);
+		mainGrid.Add(secondCollectionView, 0, 1);
+
+		Content = mainGrid;
+	}
+}
+
+public class Issue33324ViewModel : INotifyPropertyChanged
+{
+	bool _hasItems;
+	ObservableCollection<string> _myItems;
+	ObservableCollection<string> _players;
+
+	public Issue33324ViewModel()
+	{
+		_myItems = new ObservableCollection<string>();
+		_players = new ObservableCollection<string>();
+		_hasItems = false;
+
+		LoadItemsCommand = new Command(LoadItems);
+	}
+
+	public bool HasItems
+	{
+		get => _hasItems;
+		set
+		{
+			if (_hasItems != value)
+			{
+				_hasItems = value;
+				OnPropertyChanged();
+			}
+		}
+	}
+
+	public ObservableCollection<string> MyItems
+	{
+		get => _myItems;
+		set
+		{
+			if (_myItems != value)
+			{
+				_myItems = value;
+				OnPropertyChanged();
+			}
+		}
+	}
+
+	public ObservableCollection<string> Players
+	{
+		get => _players;
+		set
+		{
+			if (_players != value)
+			{
+				_players = value;
+				OnPropertyChanged();
+			}
+		}
+	}
+
+	public Command LoadItemsCommand { get; }
+
+	void LoadItems()
+	{
+		MyItems.Clear();
+		for (int i = 1; i <= 10; i++)
+		{
+			MyItems.Add($"Item {i}");
+		}
+		HasItems = true;
+	}
+
+	public event PropertyChangedEventHandler PropertyChanged;
+
+	protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
+	{
+		PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue33324.cs

@@ -0,0 +1,22 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue33324 : _IssuesUITest
+{
+    public override string Issue => "CollectionView.EmptyView does not remeasure its height when the parent layout changes dynamically";
+
+    public Issue33324(TestDevice device) : base(device) { }
+
+    [Test]
+    [Category(UITestCategories.CollectionView)]
+    public void EmptyViewShouldRemeasureWhenParentLayoutChanges()
+    {
+        App.WaitForElement("LoadItemsButton");
+        App.Tap("LoadItemsButton");
+        App.WaitForElement("SecondCollectionView");
+        VerifyScreenshot();
+    }
+}