[ios,tests] Fix iOS Header with Group

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

@@ -46,6 +46,16 @@ protected override void Dispose(bool disposing)
 					_footerViewFormsElement.MeasureInvalidated -= OnFormsElementMeasureInvalidated;
 				}
 
+				if (_headerUIView is MauiView hv)
+				{
+					hv.LayoutChanged -= HeaderViewLayoutChanged;
+				}
+
+				if (_footerUIView is MauiView fv)
+				{
+					fv.LayoutChanged -= FooterViewLayoutChanged;
+				}
+
 				_headerUIView = null;
 				_headerViewFormsElement = null;
 				_footerUIView = null;
@@ -105,15 +115,26 @@ internal void UpdateFooterView()
 			UpdateSubview(ItemsView?.Footer, ItemsView?.FooterTemplate, FooterTag,
 				ref _footerUIView, ref _footerViewFormsElement);
 			UpdateHeaderFooterPosition();
+
+			if (_footerUIView is MauiView mv)
+			{
+				mv.LayoutChanged += FooterViewLayoutChanged;
+			}
 		}
 
 		internal void UpdateHeaderView()
 		{
 			UpdateSubview(ItemsView?.Header, ItemsView?.HeaderTemplate, HeaderTag,
 				ref _headerUIView, ref _headerViewFormsElement);
 			UpdateHeaderFooterPosition();
+
+			if(_headerUIView is MauiView mv)
+			{
+				mv.LayoutChanged += HeaderViewLayoutChanged;
+			}
 		}
 
+
 		internal void UpdateSubview(object view, DataTemplate viewTemplate, nint viewTag, ref UIView uiView, ref VisualElement formsElement)
 		{
 			uiView?.RemoveFromSuperview();
@@ -239,5 +260,15 @@ internal void UpdateLayoutMeasurements()
 			if (_footerViewFormsElement != null)
 				HandleFormsElementMeasureInvalidated(_footerViewFormsElement);
 		}
+
+		void HeaderViewLayoutChanged(object sender, EventArgs e)
+		{
+			HandleFormsElementMeasureInvalidated(_headerViewFormsElement);
+		}
+
+		void FooterViewLayoutChanged(object sender, EventArgs e)
+		{
+			HandleFormsElementMeasureInvalidated(_footerViewFormsElement);
+		}
 	}
 }

src/Controls/src/Core/Handlers/Items2/CollectionViewHandler2.iOS.cs

@@ -149,8 +149,8 @@ protected override UICollectionViewLayout SelectLayout()
 				{
 					headerFooterInfo.FooterView = footerView;
 				}
-				headerFooterInfo.HasHeader = structuredItemsView.Header is not null;
-				headerFooterInfo.HasFooter = structuredItemsView.Footer is not null;
+				headerFooterInfo.HasHeader = structuredItemsView.Header is not null || structuredItemsView.HeaderTemplate is not null;
+				headerFooterInfo.HasFooter = structuredItemsView.Footer is not null || structuredItemsView.FooterTemplate is not null;
 			}
 
 			var itemSizingStrategy = ItemsView.ItemSizingStrategy;

src/Controls/src/Core/Handlers/Items2/iOS/GroupableItemsViewController2.cs

@@ -60,8 +60,8 @@ protected override void RegisterViewTypes()
 
 		private protected override void RegisterSupplementaryViews(UICollectionElementKindSection kind)
 		{
-			 base.RegisterSupplementaryViews(kind);
-			 if (IsHorizontal)
+			base.RegisterSupplementaryViews(kind);
+			if (IsHorizontal)
 			{
 				CollectionView.RegisterClassForSupplementaryView(typeof(HorizontalSupplementaryView2),
 					kind, HorizontalSupplementalView2ReuseId);
@@ -87,10 +87,15 @@ string DetermineViewReuseId(NSString elementKind)
 		public override UICollectionReusableView GetViewForSupplementaryElement(UICollectionView collectionView,
 			NSString elementKind, NSIndexPath indexPath)
 		{
-			var suplementaryViewFromStructuredView = base.GetViewForSupplementaryElement(collectionView, elementKind, indexPath);
-			if (suplementaryViewFromStructuredView is not null)
+			// If the IndexPath is less than 2, it's a header or footer for a section not a group
+			if (indexPath.Length < 2 || (ItemsView.GroupFooterTemplate is null && ItemsView.GroupHeaderTemplate is null))
 			{
-				return suplementaryViewFromStructuredView;
+
+				var suplementaryViewFromStructuredView = base.GetViewForSupplementaryElement(collectionView, elementKind, indexPath);
+				if (suplementaryViewFromStructuredView is not null)
+				{
+					return suplementaryViewFromStructuredView;
+				}
 			}
 
 			var reuseId = DetermineViewReuseId(elementKind);

src/Controls/src/Core/Handlers/Items2/iOS/ItemsViewController2.cs

@@ -401,14 +401,13 @@ protected virtual CGRect DetermineEmptyViewFrame()
 		internal void UpdateView(object view, DataTemplate viewTemplate, ref UIView uiView, ref VisualElement formsElement)
 		{
 			// Is view set on the ItemsView?
-			if (view == null)
+			if (view == null && viewTemplate is null)
 			{
 				if (formsElement != null)
 				{
 					//Platform.GetRenderer(formsElement)?.DisposeRendererAndChildren();
 				}
 
-
 				uiView?.Dispose();
 				uiView = null;
 

src/Controls/tests/TestCases.HostApp/Elements/CollectionView/CollectionViewCoreGalleryPage.cs

@@ -1,4 +1,6 @@
 using Controls.Sample.UITests;
+using Maui.Controls.Sample.CollectionViewGalleries.GroupingGalleries;
+using Maui.Controls.Sample.CollectionViewGalleries.HeaderFooterGalleries;
 using Maui.Controls.Sample.CollectionViewGalleries.ItemSizeGalleries;
 using Maui.Controls.Sample.CollectionViewGalleries.SelectionGalleries;
 
@@ -35,6 +37,8 @@ public CollectionViewCoreGalleryContentPage()
 						// VisitAndUpdateItemsSource (src\Compatibility\ControlGallery\src\UITests.Shared\Tests\CollectionViewUITests.cs)
 						TestBuilder.NavButton("Default Text Galleries", () => new DefaultTextGallery(), Navigation),
 						TestBuilder.NavButton("DataTemplate Galleries", () => new DataTemplateGallery(), Navigation),
+						TestBuilder.NavButton("Grouping Galleries", () => new GroupingGallery(), Navigation),
+						TestBuilder.NavButton("Header Footer Galleries", () => new HeaderFooterGallery(), Navigation),
 						TestBuilder.NavButton("Observable Collection Galleries", () => new ObservableCollectionGallery(), Navigation),
 						// SelectionShouldUpdateBinding (src\Compatibility\ControlGallery\src\Issues.Shared\CollectionViewBoundSingleSelection.cs)
 						// ItemsFromViewModelShouldBeSelected (src\Compatibility\ControlGallery\src\Issues.Shared\CollectionViewBoundMultiSelection.cs)

src/Controls/tests/TestCases.HostApp/Elements/CollectionView/HeaderFooterGalleries/HeaderFooterTemplate.xaml.cs

@@ -26,7 +26,7 @@ class HeaderFooterDemoModel : INotifyPropertyChanged
 
 			public HeaderFooterDemoModel()
 			{
-				CurrentTime = DateTime.Now;
+				CurrentTime = new DateTime(2023,1,1);
 			}
 
 			void OnPropertyChanged([CallerMemberName] string property = "")
@@ -36,7 +36,7 @@ void OnPropertyChanged([CallerMemberName] string property = "")
 
 			public ObservableCollection<CollectionViewGalleryTestItem> Items => _demoFilteredItemSource.Items;
 
-			public ICommand TapCommand => new Command(() => { CurrentTime = DateTime.Now; });
+			public ICommand TapCommand => new Command(() => { CurrentTime = new DateTime(2024,1,1); });
 
 			public DateTime CurrentTime
 			{

src/Controls/tests/TestCases.HostApp/Issues/Issue20443.xaml

@@ -0,0 +1,44 @@
+<?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="Controls.TestCases.HostApp.Issues.Issue20443"
+              xmlns:local="clr-namespace:Controls.TestCases.HostApp.Issues"
+              x:DataType="local:Issue20443ViewModel"
+             Title="Issue20443">
+  <ContentPage.BindingContext>
+        <local:Issue20443ViewModel/>
+    </ContentPage.BindingContext>
+    <Grid>
+        <RefreshView
+            IsRefreshing="{Binding IsRefreshing}"
+            Command="{Binding RefreshCommand}">
+            <CollectionView
+                ItemSizingStrategy="MeasureAllItems"
+                ItemsSource="{Binding Items}">
+                <CollectionView.ItemTemplate>
+                    <local:Issue20443TemplateSelector>
+                        <local:Issue20443TemplateSelector.ItemATemplate>
+                            <DataTemplate>
+                                <Grid
+                                    HeightRequest="20"
+                                    BackgroundColor="Aqua">
+                                    <Label Text="20"/>
+                                </Grid>
+                            </DataTemplate>
+                        </local:Issue20443TemplateSelector.ItemATemplate>
+                        <local:Issue20443TemplateSelector.ItemBTemplate>
+                            <DataTemplate>
+                                <Grid
+                                    HeightRequest="100"
+                                    BackgroundColor="Pink">
+                                    <Label Text="100"/>
+                                </Grid>
+                            </DataTemplate>
+                        </local:Issue20443TemplateSelector.ItemBTemplate>
+                    </local:Issue20443TemplateSelector>
+                </CollectionView.ItemTemplate>
+
+            </CollectionView>
+        </RefreshView>
+    </Grid>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue20443.xaml.cs

@@ -0,0 +1,90 @@
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Threading.Tasks;
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.Xaml;
+using System.Runtime.CompilerServices;
+
+namespace Controls.TestCases.HostApp.Issues
+{
+	[Issue(IssueTracker.Github, 20443, "CollectionView item gets wrong size after refresh", PlatformAffected.iOS)]
+
+	public partial class Issue20443 : ContentPage
+	{
+		public Issue20443()
+		{
+			InitializeComponent();
+		}
+	}
+	public class Issue20443ViewModel : INotifyPropertyChanged
+	{
+		public IList<object> Items { get; set; }
+
+		private bool _isRefreshing;
+
+		public bool IsRefreshing
+		{
+			get => _isRefreshing;
+			set
+			{
+				_isRefreshing = value;
+				OnPropertyChanged();
+			}
+		}
+
+		public Command RefreshCommand { get; set; }
+
+		public Issue20443ViewModel()
+		{
+			RefreshCommand = new Command(
+				async () =>
+				{
+					await Task.Delay(2000);
+					IsRefreshing = false;
+				});
+
+			Items = new List<object>();
+			for (int i = 0; i < 100; i++)
+			{
+				Items.Add(new Issue20443ItemA());
+				Items.Add(new Issue20443ItemB());
+				Items.Add(new Issue20443ItemB());
+				Items.Add(new Issue20443ItemB());
+				Items.Add(new Issue20443ItemB());
+			}
+		}
+
+		public event PropertyChangedEventHandler PropertyChanged;
+
+		protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
+		{
+			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+		}
+	}
+
+	public class Issue20443ItemA
+	{
+
+	}
+
+	public class Issue20443ItemB
+	{
+
+	}
+
+	public class Issue20443TemplateSelector : DataTemplateSelector
+	{
+		public DataTemplate ItemATemplate { get; set; }
+		public DataTemplate ItemBTemplate { get; set; }
+
+		protected override DataTemplate OnSelectTemplate(object item, BindableObject container)
+		{
+			if (item is Issue20443ItemA)
+			{
+				return ItemATemplate;
+			}
+
+			return ItemBTemplate;
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/CollectionView/CollectionViewUITests.Grouping.cs

@@ -0,0 +1,34 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests
+{
+#if IOS
+    public class CollectionViewGroupingTests : CollectionViewUITests
+    {
+        protected override bool ResetAfterEachTest => true;
+
+        public CollectionViewGroupingTests(TestDevice device)
+            : base(device)
+        {
+        }
+
+        [Test]
+        [Category(UITestCategories.CollectionView)]
+        public void GroupingAndHeaderWorks()
+        {
+            VisitInitialGallery("Grouping");
+
+            VisitSubGallery("Basic Grouping");
+
+            // header
+            App.WaitForElement("This is a header");
+            // group header
+            App.WaitForElement("Avengers");
+            // group footer
+            App.WaitForElement("Total members: 12");
+        }
+    }
+#endif 
+}