Fix iOS CollectionView not reacting properly to orientation changes

Author: albyrock87

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

@@ -99,6 +99,12 @@ public override UICollectionViewLayoutAttributes PreferredLayoutAttributesFittin
 			{
 				// Measure this cell (including the Forms element) if there is no constrained size
 				var size = ConstrainedSize == default ? Measure() : ConstrainedSize;
+				if (size != _size)
+				{
+					// While the platform view Frame is set via auto-layout constraints,
+					// We have to force a layout pass on the platform view to ensure it's correctly laid out.
+					ContentView.Subviews.FirstOrDefaultNoLinq()?.SetNeedsLayout();
+				}
 
 				_size = size.ToSize();
 				_measureInvalidated = false;
@@ -112,23 +118,6 @@ public override UICollectionViewLayoutAttributes PreferredLayoutAttributesFittin
 			return preferredAttributes;
 		}
 
-		public override void LayoutSubviews()
-		{
-			if (PlatformHandler?.VirtualView is { } virtualView)
-			{
-				// While the platform view Frame is set via auto-layout constraints,
-				// we have to set the Frame on the virtual view manually.
-				// Subviews will eventually be arranged via LayoutSubviews once the cell comes into play.
-				var frame = new Rect(Point.Zero, Bounds.Size.ToSize());
-				if (virtualView.Frame != frame)
-				{
-					virtualView.Arrange(frame);
-				}
-			}
-
-			base.LayoutSubviews();
-		}
-
 		[Obsolete]
 		[EditorBrowsable(EditorBrowsableState.Never)]
 		protected void Layout(CGSize constraints)

src/Controls/src/Core/Handlers/Items2/iOS/TemplatedCell2.cs

@@ -92,6 +92,13 @@ public override UICollectionViewLayoutAttributes PreferredLayoutAttributesFittin
 				if (_measureInvalidated || _cachedConstraints != constraints)
 				{
 					var measure = virtualView.Measure(constraints.Width, constraints.Height);
+					if (_measuredSize != measure)
+					{
+						// While the platform view Frame is set via auto-layout constraints,
+						// We have to force a layout pass on the platform view to ensure it's correctly laid out.
+						ContentView.Subviews.FirstOrDefaultNoLinq()?.SetNeedsLayout();
+					}
+
 					_cachedConstraints = constraints;
 					_measuredSize = measure;
 				}
@@ -109,23 +116,6 @@ public override UICollectionViewLayoutAttributes PreferredLayoutAttributesFittin
 			return preferredAttributes;
 		}
 
-		public override void LayoutSubviews()
-		{
-			if (PlatformHandler?.VirtualView is { } virtualView)
-			{
-				// While the platform view Frame is set via auto-layout constraints,
-				// we have to set the Frame on the virtual view manually.
-				// Subviews will eventually be arranged via LayoutSubviews once the cell comes into play.
-				var frame = new Rect(Point.Zero, Bounds.Size.ToSize());
-				if (virtualView.Frame != frame)
-				{
-					virtualView.Arrange(frame);
-				}
-			}
-
-			base.LayoutSubviews();
-		}
-
 		public override void PrepareForReuse()
 		{
 			//Unbind();

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

@@ -1,7 +1,5 @@
 #nullable enable
 Microsoft.Maui.Controls.StyleableElement.Style.get -> Microsoft.Maui.Controls.Style?
-override Microsoft.Maui.Controls.Handlers.Items.TemplatedCell.LayoutSubviews() -> void
-override Microsoft.Maui.Controls.Handlers.Items2.TemplatedCell2.LayoutSubviews() -> 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

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

@@ -1,7 +1,5 @@
 #nullable enable
 Microsoft.Maui.Controls.StyleableElement.Style.get -> Microsoft.Maui.Controls.Style?
-override Microsoft.Maui.Controls.Handlers.Items.TemplatedCell.LayoutSubviews() -> void
-override Microsoft.Maui.Controls.Handlers.Items2.TemplatedCell2.LayoutSubviews() -> 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

src/Controls/tests/TestCases.HostApp/Issues/Issue28657.cs

@@ -0,0 +1,38 @@
+namespace Controls.TestCases.HostApp.Issues;
+
+[Issue(IssueTracker.Github, 28657, "iOS - Rotating the simulator would cause clipping on the description text", PlatformAffected.iOS)]
+class Issue28657 : ContentPage
+{
+	public Issue28657()
+	{
+		var cv = new CollectionView();
+		cv.ItemTemplate = new DataTemplate(() =>
+		{
+			var label = new Label();
+			label.BackgroundColor = Colors.DeepSkyBlue;
+			label.LineBreakMode = LineBreakMode.CharacterWrap;
+			label.SetBinding(Label.TextProperty, ".");
+			var vsl = new VerticalStackLayout { Padding = 8 };
+			vsl.Add(label);
+			vsl.BackgroundColor = Colors.SlateBlue;
+			return vsl;
+		});
+		cv.ItemsSource = Enumerable.Range(0, 30)
+			.Select(x => x + ": Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec a diam lectus. Sed sit amet ipsum mauris. Maecenas congue ligula ac quam viverra nec consectetur ante hendrerit.")
+			.ToList();
+		var label = new Label
+		{
+			AutomationId = "StubLabel",
+			Text = "Rotate the device until you get back to portrait mode. The text should wrap normally on each row.",
+		};
+		var grid = new Grid
+		{
+			RowDefinitions = new RowDefinitionCollection(
+				new RowDefinition(GridLength.Auto),
+				new RowDefinition(GridLength.Star))
+		};
+		grid.Add(label);
+		grid.Add(cv, 0, 1);
+		Content = grid;
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue25671.cs

@@ -43,12 +43,12 @@ public async Task LayoutPassesShouldNotIncrease()
 
 #if IOS
             var maxMeasurePasses = 221;
-            var maxArrangePasses = 237;
+            var maxArrangePasses = 186;
 
             if (App.FindElement("HeadingLabel").GetText() == "CollectionViewHandler2")
             {
-	            maxMeasurePasses = 362;
-	            maxArrangePasses = 398;
+	            maxMeasurePasses = 340;
+	            maxArrangePasses = 310;
             }
 #elif ANDROID
 			const int maxMeasurePasses = 353;
@@ -64,9 +64,9 @@ public async Task LayoutPassesShouldNotIncrease()
 			TestContext.AddTestAttachment(logFile, "LayoutPasses.log");
 
 			// Then assert that the measure passes and arrange passes are less than the expected values.
-			// Let's give a 5% margin of error.
-			ClassicAssert.LessOrEqual(measurePasses, maxMeasurePasses * 1.05);
-			ClassicAssert.LessOrEqual(arrangePasses, maxArrangePasses * 1.05);
+			// Let's give a 10% margin of error due to CI variability.
+			ClassicAssert.LessOrEqual(measurePasses, maxMeasurePasses * 1.1);
+			ClassicAssert.LessOrEqual(arrangePasses, maxArrangePasses * 1.1);
 		}
 
 		async Task ScrollDown()

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28657.cs

@@ -0,0 +1,28 @@
+#if IOS
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue28657 : _IssuesUITest
+{
+    public override string Issue => "iOS - Rotating the simulator would cause clipping on the description text";
+    public Issue28657(TestDevice device) : base(device)
+    {
+    }
+
+    [Test]
+    [Category(UITestCategories.CollectionView)]
+    public void CellLayoutUpdatesCorrectlyAfterDeviceOrientationChanges()
+    {
+        App.WaitForElement("StubLabel");
+        App.SetOrientationLandscape();
+        Thread.Sleep(400);
+        VerifyScreenshot("Issue28657_Landscape");
+        App.SetOrientationPortrait();
+        Thread.Sleep(400);
+        VerifyScreenshot("Issue28657_Portrait");
+    }
+}
+#endif