[iOS] Fix SwipeView programmatic open when background color is set.

src/Controls/tests/TestCases.HostApp/Issues/Issue17204.cs

@@ -0,0 +1,63 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 17204, "SwipeView does not work correctly on iOS when opened programmatically", PlatformAffected.iOS)]
+public class Issue17204 : ContentPage
+{
+	public Issue17204()
+	{
+		var verticalStack = new VerticalStackLayout
+		{
+			Spacing = 20,
+			Padding = new Thickness(20)
+		};
+
+		var swipeView = new SwipeView
+		{
+			Background = Colors.LightPink,
+		};
+
+		var label = new Label
+		{
+			HeightRequest = 200,
+			VerticalTextAlignment = TextAlignment.Center,
+			Text = "Programmatic swipe works"
+		};
+
+		var swipeItemView = new SwipeItemView
+		{
+			Background = Colors.LightGreen,
+			Content = label,
+		};
+
+		var swipeItems = new SwipeItems();
+		swipeItems.Add(swipeItemView);
+		swipeView.RightItems = swipeItems;
+
+		var contentLabel = new Label
+		{
+			HeightRequest = 200,
+			VerticalTextAlignment = TextAlignment.Center,
+			Text = "Swipe view"
+		};
+
+		swipeView.Content = new SwipeItemView
+		{
+			Content = contentLabel
+		};
+
+		var button = new Button
+		{
+			Text = "Open SwipeView",
+			AutomationId = "OpenSwipeViewButton"
+		};
+
+		button.Clicked += (sender, e) =>
+		{
+			swipeView.Open(OpenSwipeItem.RightItems, false);
+		};
+
+		verticalStack.Add(swipeView);
+		verticalStack.Add(button);
+		Content = verticalStack;
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue17204.cs

@@ -0,0 +1,24 @@
+#if TEST_FAILS_ON_WINDOWS // Cannot open programatically a SwipeView on Windows.
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue17204 : _IssuesUITest
+{
+    public override string Issue => "SwipeView does not work correctly on iOS when opened programmatically";
+
+    public Issue17204(TestDevice device)
+    : base(device)
+    { }
+
+    [Test]
+    [Category(UITestCategories.SwipeView)]
+    public void ProgrammaticallyOpenedSwipeViewShouldBeVisible()
+    {
+        App.WaitForElement("OpenSwipeViewButton");
+        App.Tap("OpenSwipeViewButton");
+        VerifyScreenshot();
+    }
+}
+#endif

src/Core/src/Platform/iOS/MauiSwipeView.cs

@@ -1144,11 +1144,12 @@ internal void ProgrammaticallyOpenSwipeItem(OpenSwipeItem openSwipeItem, bool an
 				return;
 
 			UpdateIsOpen(true);
+			UpdateSwipeItems();
 
 			var swipeThreshold = GetSwipeThreshold();
 			UpdateOffset(swipeThreshold);
 
-			UpdateSwipeItems();
+			LayoutIfNeeded();
 			Swipe(animated);
 
 			_swipeOffset = Math.Abs(_swipeOffset);