[iOS] CollectionView footer sizing when source is empty - fix (#28610)

* [iOS] CollectionView footer sizing fix

* Added snapshots

* Added Macos snapshot

* Update StructuredItemsViewController.cs

* Update StructuredItemsViewController.cs

Author: kubaflo

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

@@ -206,7 +206,7 @@ void UpdateHeaderFooterPosition()
 					}
 				}
 
-				if (_headerUIView != null && _headerUIView.Frame.Y != headerHeight)
+				if (_headerUIView != null && (_headerUIView.Frame.Y != -headerHeight || _headerUIView.Frame.Width != CollectionView.Frame.Width))
 				{
 					_headerUIView.Frame = new CoreGraphics.CGRect(0, -headerHeight, CollectionView.Frame.Width, headerHeight);
 				}
@@ -218,7 +218,7 @@ void UpdateHeaderFooterPosition()
 					height = ItemsViewLayout.CollectionViewContentSize.Height;
 				}
 
-				if (_footerUIView != null && (_footerUIView.Frame.Y != height || emptyHeight > 0 || _footerUIView.Frame.Height != footerHeight))
+				if (_footerUIView != null && (_footerUIView.Frame.Y != height || emptyHeight > 0 || _footerUIView.Frame.Height != footerHeight || _footerUIView.Frame.Width != CollectionView.Frame.Width))
 				{
 					_footerUIView.Frame = new CoreGraphics.CGRect(0, height + emptyHeight, CollectionView.Frame.Width, footerHeight);
 				}

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

@@ -0,0 +1,58 @@
+<?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"
+             xmlns:local="clr-namespace:Maui.Controls.Sample.Issues"
+             x:Class="Maui.Controls.Sample.Issues.Issue28580">
+    <Grid Padding="30">
+        <CollectionView>
+            <CollectionView.Header>
+                <Border
+                    Stroke="Black"
+                    Margin="0">
+                    <Grid
+                        ColumnDefinitions="*,Auto"
+                        ColumnSpacing="5">
+                        <Label
+                            Grid.Column="1"
+                            Text="add new"
+                            HorizontalOptions="Center"
+                            VerticalOptions="Center"
+                            VerticalTextAlignment="Center"/>
+
+                        <Label
+                            Grid.Column="0"
+                            Text="+"
+                            HorizontalOptions="End"
+                            VerticalOptions="Center"
+                            VerticalTextAlignment="Center"/>
+                    </Grid>
+                </Border>
+            </CollectionView.Header>
+
+            <CollectionView.Footer>
+                <Border
+                    Stroke="Black"
+                    Margin="0">
+                    <Grid
+                        ColumnDefinitions="*,Auto"
+                        ColumnSpacing="5">
+                        <Label
+                            Grid.Column="1"
+                            Text="add new"
+                            AutomationId="labelInFooter"
+                            HorizontalOptions="Center"
+                            VerticalOptions="Center"
+                            VerticalTextAlignment="Center"/>
+
+                        <Label
+                            Grid.Column="0"
+                            Text="+"
+                            HorizontalOptions="End"
+                            VerticalOptions="Center"
+                            VerticalTextAlignment="Center"/>
+                    </Grid>
+                </Border>
+            </CollectionView.Footer>
+        </CollectionView>
+    </Grid>
+</ContentPage> 

src/Controls/tests/TestCases.HostApp/Issues/Issue28580.xaml

@@ -0,0 +1,10 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 28580, "CollectionView footer sizing when source is empty")]
+public partial class Issue28580 : ContentPage
+{
+	public Issue28580()
+	{
+		InitializeComponent();
+	}
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue28580.xaml.cs

@@ -0,0 +1,21 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+public class Issue28580 : _IssuesUITest
+{
+	public Issue28580(TestDevice testDevice) : base(testDevice)
+	{
+	}
+
+	public override string Issue => "CollectionView footer sizing when source is empty";
+
+	[Test]
+	[Category(UITestCategories.CollectionView)]
+	public void FooterWithEmptyCVShouldHaveCorrectSize()
+	{
+		App.WaitForElement("labelInFooter");
+		VerifyScreenshot();
+	}
+}