Fix endless loop

Author: albyrock87

src/Controls/src/Core/Handlers/Items2/ItemsViewHandler2.iOS.cs

@@ -175,6 +175,35 @@ protected bool IsIndexPathValid(NSIndexPath indexPath)
 			return true;
 		}
 
+		public override Size GetDesiredSize(double widthConstraint, double heightConstraint)
+		{
+			var size = base.GetDesiredSize(widthConstraint, heightConstraint);
+
+			var potentialContentSize = Controller.GetSize();
+
+			// If contentSize comes back null, it means none of the content has been realized yet;
+			// we need to return the expansive size the collection view wants by default to get
+			// it to start measuring its content
+			if (potentialContentSize == null)
+			{
+				return size;
+			}
+
+			var contentSize = potentialContentSize.Value;
+
+			// If contentSize does have a value, our target size is the smaller of it and the constraints
+
+			size.Width = contentSize.Width <= widthConstraint ? contentSize.Width : widthConstraint;
+			size.Height = contentSize.Height <= heightConstraint ? contentSize.Height : heightConstraint;
+
+			var virtualView = this.VirtualView as IView;
+
+			size.Width = ViewHandlerExtensions.ResolveConstraints(size.Width, virtualView.Width, virtualView.MinimumWidth, virtualView.MaximumWidth);
+			size.Height = ViewHandlerExtensions.ResolveConstraints(size.Height, virtualView.Height, virtualView.MinimumHeight, virtualView.MaximumHeight);
+
+			return size;
+		}
+
 		// public override Size GetDesiredSize(double widthConstraint, double heightConstraint)
 		// {
 		// 	var size = base.GetDesiredSize(widthConstraint, heightConstraint);

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

@@ -211,6 +211,16 @@ internal void DisposeItemsSource()
 			CollectionView.ReloadData();
 		}
 
+		internal Size? GetSize()
+		{
+			if (_emptyViewDisplayed)
+			{
+				return _emptyUIView.Frame.Size.ToSize();
+			}
+
+			return CollectionView.CollectionViewLayout.CollectionViewContentSize.ToSize();
+		}
+
 		void EnsureLayoutInitialized()
 		{
 			if (_initialized)

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

@@ -1,6 +1,7 @@
 #nullable enable
 Microsoft.Maui.Controls.StyleableElement.Style.get -> Microsoft.Maui.Controls.Style?
 override Microsoft.Maui.Controls.Handlers.Compatibility.VisualElementRenderer<TElement>.MovedToWindow() -> void
+override Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.CreateController(TItemsView newElement, UIKit.UICollectionViewLayout layout) -> Microsoft.Maui.Controls.Handlers.Items2.ItemsViewController2<TItemsView>
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.SelectLayout() -> UIKit.UICollectionViewLayout
 *REMOVED*~Microsoft.Maui.Controls.Handlers.Compatibility.ShellScrollViewTracker.ShellScrollViewTracker(Microsoft.Maui.IPlatformViewHandler renderer) -> void

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

@@ -1,6 +1,7 @@
 #nullable enable
 Microsoft.Maui.Controls.StyleableElement.Style.get -> Microsoft.Maui.Controls.Style?
 override Microsoft.Maui.Controls.Handlers.Compatibility.VisualElementRenderer<TElement>.MovedToWindow() -> void
+override Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.CreateController(TItemsView newElement, UIKit.UICollectionViewLayout layout) -> Microsoft.Maui.Controls.Handlers.Items2.ItemsViewController2<TItemsView>
 ~abstract Microsoft.Maui.Controls.Handlers.Items2.ItemsViewHandler2<TItemsView>.SelectLayout() -> UIKit.UICollectionViewLayout
 *REMOVED*~Microsoft.Maui.Controls.Handlers.Compatibility.ShellScrollViewTracker.ShellScrollViewTracker(Microsoft.Maui.IPlatformViewHandler renderer) -> void

src/Controls/tests/TestCases.HostApp/Issues/Issue14557.cs

@@ -5,16 +5,29 @@ class Issue14557 : TestContentPage
 	{
 		protected override void Init()
 		{
-			var scrollView = new ScrollView();
+			var scrollView = new ScrollView
+			{
+				BackgroundColor = Colors.Coral,
+				Padding = 24
+			};
 
 			var headerLabel = new Label { AutomationId = "headerLabel", Text = "Foo", };
 			var footerLabel = new Label { AutomationId = "footerLabel", Text = "Bar" };
 
-			var collectionView = new CollectionView { Header = headerLabel, Footer = footerLabel, AutomationId = "collectionView" };
+			var collectionView = new CollectionView
+			{
+				Header = headerLabel,
+				Footer = footerLabel,
+				AutomationId = "collectionView",
+				BackgroundColor = Colors.Beige,
+			};
 
 			scrollView.Content = collectionView;
 
-			Content = scrollView;
+			Content = new Grid
+			{
+				scrollView
+			};
 		}
 	}
 }