[iOS] Fixes carouselview layout on iOS

src/Controls/samples/Controls.Sample.UITests/Issues/Issue19657.xaml

@@ -0,0 +1,31 @@
+<?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.Issue19657"
+             xmlns:ns="clr-namespace:Maui.Controls.Sample.Issues">
+    <ScrollView>
+        <Grid x:Name="contentGrid">
+            <Grid.RowDefinitions>
+                <RowDefinition Height="20" />
+                <RowDefinition Height="220" />
+            </Grid.RowDefinitions>
+            <Grid.Resources>
+                <DataTemplate x:Key="SampleItemTemplate">
+                    <VerticalStackLayout Spacing="4">
+                        <Label Text="{Binding Title, Mode=OneWay}" FontAttributes="Bold" />
+                        <Label Text="{Binding Description, Mode=OneWay}" />
+                    </VerticalStackLayout>
+                </DataTemplate>
+            </Grid.Resources>
+
+            <Label HorizontalOptions="Center" x:Name="WaitHere" Text="Check if the Carousel items all show up" AutomationId="WaitHere" Background="Red"/>
+
+            <CarouselView x:Name="carousel"
+                         ItemTemplate="{StaticResource SampleItemTemplate}"
+                         Loop="False"
+                         HeightRequest="220"
+                         Grid.Row="1"
+                         BackgroundColor="LightBlue" />
+        </Grid>
+    </ScrollView>
+</ContentPage>

src/Controls/samples/Controls.Sample.UITests/Issues/Issue19657.xaml.cs

@@ -0,0 +1,43 @@
+using System;
+using System.ComponentModel;
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.Xaml;
+using Microsoft.Maui.Graphics;
+using System.Collections.Generic;
+
+namespace Maui.Controls.Sample.Issues
+{
+	[XamlCompilation(XamlCompilationOptions.Compile)]
+	[Issue(IssueTracker.Github, 19657, "CarouselView Content disappears when 'Loop' is false and inside ScrollView", PlatformAffected.iOS)]
+	public partial class Issue19657 : ContentPage
+	{
+
+		public Issue19657()
+		{
+			InitializeComponent();
+			var exampleItems = new List<SampleCarouselItem1>
+			{
+				new SampleCarouselItem1( "First", "First CarouselView item" ),
+				new SampleCarouselItem1( "Second", "Second CarouselView item" ),
+				new SampleCarouselItem1( "Third", "Third CarouselView item" ),
+				new SampleCarouselItem1( "Fourth", "Fourth CarouselView item" ),
+				new SampleCarouselItem1( "Fifth", "Fifth CarouselView item" ),
+			};
+
+			carousel.ItemsSource = exampleItems;
+		}
+
+		class SampleCarouselItem1
+		{
+    		public SampleCarouselItem1(string title, string description )
+    		{
+        		Title = title;
+        		Description = description;
+    		}
+
+    		public string Title { get; set; }
+    		public string Description { get; set; }
+			public Color Color { get; set; }
+		}
+	}
+}

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

@@ -1,5 +1,6 @@
 #nullable disable
 using System;
+using Microsoft.Maui.Graphics;
 
 namespace Microsoft.Maui.Controls.Handlers.Items
 {
@@ -64,5 +65,8 @@ public static void MapLoop(CarouselViewHandler handler, CarouselView carouselVie
 		{
 			(handler.Controller as CarouselViewController)?.UpdateLoop();
 		}
+
+		public override Size GetDesiredSize(double widthConstraint, double heightConstraint) => 
+			this.GetDesiredSizeFromHandler(widthConstraint, heightConstraint);
 	}
 }

src/Controls/src/Core/PublicAPI/net-ios/PublicAPI.Unshipped.txt

@@ -179,6 +179,7 @@ Microsoft.Maui.Controls.IValueConverter.ConvertBack(object? value, System.Type!
 *REMOVED*override Microsoft.Maui.Controls.Handlers.Compatibility.PhoneFlyoutPageRenderer.WillRotate(UIKit.UIInterfaceOrientation toInterfaceOrientation, double duration) -> void
 ~virtual Microsoft.Maui.Controls.Handlers.Items.ItemsViewController<TItemsView>.DetermineCellReuseId(Foundation.NSIndexPath indexPath) -> string
 override Microsoft.Maui.Controls.Handlers.Items.ItemsViewHandler<TItemsView>.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
+override Microsoft.Maui.Controls.Handlers.Items.CarouselViewHandler.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 ~Microsoft.Maui.Controls.Element.AddLogicalChild(Microsoft.Maui.Controls.Element element) -> void
 ~Microsoft.Maui.Controls.Element.InsertLogicalChild(int index, Microsoft.Maui.Controls.Element element) -> void
 ~Microsoft.Maui.Controls.Element.RemoveLogicalChild(Microsoft.Maui.Controls.Element element) -> bool

src/Controls/src/Core/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt

@@ -175,6 +175,7 @@ Microsoft.Maui.Controls.IValueConverter.ConvertBack(object? value, System.Type!
 *REMOVED*override Microsoft.Maui.Controls.Handlers.Compatibility.PhoneFlyoutPageRenderer.WillRotate(UIKit.UIInterfaceOrientation toInterfaceOrientation, double duration) -> void
 ~virtual Microsoft.Maui.Controls.Handlers.Items.ItemsViewController<TItemsView>.DetermineCellReuseId(Foundation.NSIndexPath indexPath) -> string
 override Microsoft.Maui.Controls.Handlers.Items.ItemsViewHandler<TItemsView>.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
+override Microsoft.Maui.Controls.Handlers.Items.CarouselViewHandler.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 ~Microsoft.Maui.Controls.Element.AddLogicalChild(Microsoft.Maui.Controls.Element element) -> void
 ~Microsoft.Maui.Controls.Element.InsertLogicalChild(int index, Microsoft.Maui.Controls.Element element) -> void
 ~Microsoft.Maui.Controls.Element.RemoveLogicalChild(Microsoft.Maui.Controls.Element element) -> bool

src/Controls/tests/UITests/Tests/Issues/Issue19657.cs

@@ -0,0 +1,27 @@
+using System.Drawing;
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.AppiumTests.Issues
+{
+	public class Issue19657 : _IssuesUITest
+	{
+		public Issue19657(TestDevice device) : base(device) { }
+
+		public override string Issue => "CarouselView Content disappears when 'Loop' is false and inside ScrollView";
+
+		[Test]
+		public void CarouselItemLoadsInCorrectPosition()
+		{
+			_ = App.WaitForElement("WaitHere");
+
+			var element = App.WaitForElement("First");
+
+			this.IgnoreIfPlatforms(new TestDevice[] { TestDevice.Android, TestDevice.Mac, TestDevice.Windows },
+					"The bug only happens on iOS; see https://github.com/dotnet/maui/issues/19657");
+
+			VerifyScreenshot();
+		}
+	}
+}