[iOS] Fix SearchBar Black Background Issue When Setting Transparent Background

src/Controls/tests/TestCases.HostApp/Issues/Issue11677.cs

@@ -0,0 +1,47 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 11677, "[iOS][maccatalyst] SearchBar BackgroundColor is black when set to transparent", PlatformAffected.iOS)]
+public class Issue11677 : ContentPage
+{
+	public Issue11677()
+	{
+		Content = new VerticalStackLayout
+		{
+			Children =
+			{
+				new Label
+				{
+					Text = "SearchBar Transparent BackgroundColor",
+					FontSize = 16,
+					TextColor = Colors.Black,
+					AutomationId = "Label"
+				},
+				new SearchBar
+				{
+					BackgroundColor = Colors.Transparent,
+				},
+				new Label
+				{
+					Text = "SearchBar with null background",
+					FontSize = 16,
+					TextColor = Colors.Black,
+				},
+				new SearchBar
+				{
+					BackgroundColor = null,
+				},
+				new Label
+				{
+					Text = "SearchBar with default background",
+					FontSize = 16,
+					TextColor = Colors.Black,
+				},
+				new SearchBar
+				{
+					Background = Brush.Default,
+				}
+			}
+		};
+
+	}
+}	

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue11677.cs

@@ -0,0 +1,21 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+public class Issue11677 : _IssuesUITest
+{
+	public Issue11677(TestDevice testDevice) : base(testDevice)
+	{
+	}
+
+	public override string Issue => "[iOS][maccatalyst] SearchBar BackgroundColor is black when set to transparent";
+
+	[Test]
+	[Category(UITestCategories.SearchBar)]
+	public void VerifySearchBarBackground()
+	{
+		App.WaitForElement("Label");
+		VerifyScreenshot();
+	}
+}

src/Core/src/Platform/iOS/SearchBarExtensions.cs

@@ -35,14 +35,29 @@ internal static void UpdateBackground(this UISearchBar uiSearchBar, ISearchBar s
 		{
 			var background = searchBar.Background;
 
-			if (background is SolidPaint solidPaint)
-				uiSearchBar.BarTintColor = solidPaint.Color.ToPlatform();
-
-			if (background is GradientPaint gradientPaint)
-				ViewExtensions.UpdateBackground(uiSearchBar, gradientPaint);
-
-			if (background == null)
-				uiSearchBar.BarTintColor = UISearchBar.Appearance.BarTintColor;
+			switch (background)
+			{
+				case null:
+					uiSearchBar.BarTintColor = UISearchBar.Appearance.BarTintColor;
+					break;
+
+				case SolidPaint solid:
+					if (solid.Color == Colors.Transparent)
+					{
+						uiSearchBar.BackgroundImage = new UIImage();
+						uiSearchBar.BarTintColor = UIColor.Clear;
+					}
+					else
+					{
+						uiSearchBar.BackgroundImage = null;
+						uiSearchBar.BarTintColor = solid.Color.ToPlatform();
+					}
+					break;
+
+				case GradientPaint gradientPaint:
+					ViewExtensions.UpdateBackground(uiSearchBar, gradientPaint);
+					break;
+			}
 		}
 
 		public static void UpdateIsEnabled(this UISearchBar uiSearchBar, ISearchBar searchBar)