[iOS] CollectionView with header or footer has incorrect height - fix

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

@@ -270,7 +270,7 @@ void InvalidateMeasureIfContentSizeChanged()
 		}
 
 
-		internal Size? GetSize()
+		internal virtual Size? GetSize()
 		{
 			if (_emptyViewDisplayed)
 			{

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

@@ -1,6 +1,7 @@
 #nullable disable
 using System;
 using CoreGraphics;
+using Microsoft.Maui.Graphics;
 using ObjCRuntime;
 using UIKit;
 
@@ -240,6 +241,12 @@ protected override void HandleFormsElementMeasureInvalidated(VisualElement forms
 			UpdateHeaderFooterPosition();
 		}
 
+		internal override Size? GetSize()
+		{
+			var size = base.GetSize();
+			return new Size(size.Value.Width, size.Value.Height + (_headerUIView?.Frame.Height ?? 0) + (_footerUIView?.Frame.Height ?? 0));
+		}
+
 		internal void UpdateLayoutMeasurements()
 		{
 			if (_headerViewFormsElement != null)

src/Controls/tests/TestCases.HostApp/Issues/Issue27808.xaml

@@ -0,0 +1,34 @@
+<?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.Issue27808">
+<VerticalStackLayout>
+       <CollectionView>
+              <CollectionView.ItemsSource>
+                     <Array Type="{x:Type x:String}">
+                            <x:String>item1</x:String>
+                            <x:String>item2</x:String>
+                            <x:String>item3</x:String>
+                     </Array>
+              </CollectionView.ItemsSource>
+              <CollectionView.ItemTemplate>
+                     <DataTemplate>
+                            <Label AutomationId="{Binding .}"
+                                   Text="{Binding .}"/>
+                     </DataTemplate>
+              </CollectionView.ItemTemplate>
+              <CollectionView.HeaderTemplate>
+                     <DataTemplate>
+                            <BoxView HeightRequest="100"
+                                          BackgroundColor="Green"/>
+                     </DataTemplate>
+              </CollectionView.HeaderTemplate>
+              <CollectionView.FooterTemplate>
+                     <DataTemplate>
+                            <BoxView HeightRequest="200"
+                                          BackgroundColor="Blue"/>
+                     </DataTemplate>
+              </CollectionView.FooterTemplate>
+       </CollectionView>
+</VerticalStackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue27808.xaml.cs

@@ -0,0 +1,10 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 27808, "CollectionView with header or footer has incorrect height", PlatformAffected.iOS)]
+public partial class Issue27808 : ContentPage
+{
+	public Issue27808()
+	{
+		InitializeComponent();
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue27808.cs

@@ -0,0 +1,22 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue27808 : _IssuesUITest
+	{
+		public Issue27808(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "CollectionView with header or footer has incorrect height";
+
+		[Test]
+		[Category(UITestCategories.CollectionView)]
+		public void CollectionViewShouldHaveCorrectHeight()
+		{
+			App.WaitForElement("item3");
+		}
+	}
+}