[iOS] CollectionView item sizing wrong after refresh (#21736)

* [iOS] CollectionView - ItemsViewLayout: reset EstimatedItemSize and ItemSize when size cache gets cleared

Clear

* [iOS] Add Test for issue #20443

* [tests] Fix test for #20443

* [iOS] We don t want to mess with EstimatedSize when cells are clearing

---------

Co-authored-by: Rui Marinho <[email protected]>

Author: softeip

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

@@ -113,6 +113,8 @@ internal virtual bool UpdateConstraints(CGSize size)
 
 			ClearCellSizeCache();
 
+			EstimatedItemSize = CGSize.Empty;
+			
 			_currentSize = size;
 
 			var newSize = new CGSize(Math.Floor(size.Width), Math.Floor(size.Height));

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

@@ -22,7 +22,7 @@
                                 <Grid
                                     HeightRequest="20"
                                     BackgroundColor="Aqua">
-                                    <Label Text="20"/>
+                                    <Label Text="20" AutomationId="lblSmall"/>
                                 </Grid>
                             </DataTemplate>
                         </local:Issue20443TemplateSelector.ItemATemplate>
@@ -31,7 +31,7 @@
                                 <Grid
                                     HeightRequest="100"
                                     BackgroundColor="Pink">
-                                    <Label Text="100"/>
+                                    <Label Text="100" AutomationId="lblBig"/>
                                 </Grid>
                             </DataTemplate>
                         </local:Issue20443TemplateSelector.ItemBTemplate>

src/Controls/tests/TestCases.HostApp/Issues/Issue20443.xaml

@@ -7,7 +7,7 @@
 
 namespace Controls.TestCases.HostApp.Issues
 {
-	[Issue(IssueTracker.Github, 20443, "CollectionView item gets wrong size after refresh", PlatformAffected.iOS)]
+	[Issue(IssueTracker.Github, 20443, "CollectionView item sizing wrong after refresh", PlatformAffected.iOS)]
 
 	public partial class Issue20443 : ContentPage
 	{
@@ -39,7 +39,7 @@ public Issue20443ViewModel()
 			RefreshCommand = new Command(
 				async () =>
 				{
-					await Task.Delay(2000);
+					await Task.Delay(1000);
 					IsRefreshing = false;
 				});
 

src/Controls/tests/TestCases.HostApp/Issues/Issue20443.xaml.cs

@@ -0,0 +1,37 @@
+#if ANDROID || IOS
+
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue20443 : _IssuesUITest
+	{
+		public override string Issue => "CollectionView item sizing wrong after refresh";
+
+		public Issue20443(TestDevice device) : base(device)
+		{
+		}
+
+		[Test]
+		[Category(UITestCategories.CollectionView)]
+		public void RefreshShouldNotChangeSize()
+		{
+			_ = App.WaitForElement("lblSmall");
+			_ = App.WaitForElement("lblBig");
+
+			// Try pull to refresh on iOS
+			App.DragCoordinates(100, 100, 100, 500);
+
+			// wait for the fake fresh and the layout to be updated
+			Task.Delay(3000).Wait();
+
+			// Verify the size of the items
+			VerifyScreenshot();
+
+		}
+	}
+}
+
+#endif