[iOS] CollectionView footer sizing when source is empty in SR5

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

@@ -199,6 +199,12 @@ public override void ViewWillAppear(bool animated)
 		public override void ViewWillLayoutSubviews()
 		{
 			ConstrainItemsToBounds();
+
+			if (CollectionView is Items.MauiCollectionView { NeedsCellLayout: true } collectionView)
+ 			{
+ 				collectionView.NeedsCellLayout = false;
+ 			}
+
 			base.ViewWillLayoutSubviews();
 			InvalidateMeasureIfContentSizeChanged();
 			LayoutEmptyView();

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

@@ -10,6 +10,9 @@ internal class MauiCollectionView : UICollectionView, IUIViewLifeCycleEvents, IP
 	bool _invalidateParentWhenMovedToWindow;
 
 	WeakReference<ICustomMauiCollectionViewDelegate>? _customDelegate;
+
+	internal bool NeedsCellLayout { get; set; }
+
 	public MauiCollectionView(CGRect frame, UICollectionViewLayout layout) : base(frame, layout)
 	{
 	}
@@ -27,10 +30,11 @@ void IPlatformMeasureInvalidationController.InvalidateAncestorsMeasuresWhenMoved
 
 	void IPlatformMeasureInvalidationController.InvalidateMeasure(bool isPropagating)
 	{
-		if (!isPropagating)
+		if (isPropagating)
 		{
-			SetNeedsLayout();
+			NeedsCellLayout = true;
 		}
+		SetNeedsLayout();
 	}
 
 	[UnconditionalSuppressMessage("Memory", "MEM0002", Justification = IUIViewLifeCycleEvents.UnconditionalSuppressMessage)]

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

@@ -86,27 +86,23 @@ protected override CGRect DetermineEmptyViewFrame()
 
 		public override void ViewWillLayoutSubviews()
 		{
-			base.ViewWillLayoutSubviews();
-
-			// This update is only relevant if you have a footer view because it's used to place the footer view
-			// based on the ContentSize so we just update the positions if the ContentSize has changed
-			if (_footerUIView != null)
+			var hasHeaderOrFooter = _footerViewFormsElement is not null || _headerViewFormsElement is not null;
+			if (hasHeaderOrFooter && CollectionView is MauiCollectionView { NeedsCellLayout: true } collectionView)
 			{
-				var emptyView = CollectionView.ViewWithTag(EmptyTag);
-
-				if (IsHorizontal)
+				if (_headerViewFormsElement is not null)
 				{
-					if (_footerUIView.Frame.X != ItemsViewLayout.CollectionViewContentSize.Width ||
-						_footerUIView.Frame.X < emptyView?.Frame.X)
-						UpdateHeaderFooterPosition();
+					RemeasureLayout(_headerViewFormsElement);
 				}
-				else
+
+				if (_footerViewFormsElement is not null)
 				{
-					if (_footerUIView.Frame.Y != ItemsViewLayout.CollectionViewContentSize.Height ||
-						_footerUIView.Frame.Y < (emptyView?.Frame.Y + emptyView?.Frame.Height))
-						UpdateHeaderFooterPosition();
+					RemeasureLayout(_footerViewFormsElement);
 				}
+
+				UpdateHeaderFooterPosition();
 			}
+
+			base.ViewWillLayoutSubviews();
 		}
 
 		internal void UpdateFooterView()