Character spacing in button - fix

src/Controls/src/Core/Button/Button.iOS.cs

@@ -464,6 +464,9 @@ private static void MapPadding(IButtonHandler handler, Button button)
 		public static void MapText(IButtonHandler handler, Button button)
 		{
 			handler.PlatformView?.UpdateText(button);
+
+			// Any text update requires that we update any attributed string formatting
+			MapFormatting(handler, button);
 		}
 
 		internal static void MapBorderWidth(IButtonHandler handler, Button button)
@@ -477,5 +480,11 @@ private protected override void OnHandlerChangingCore(HandlerChangingEventArgs a
 			_originalImageSize = CGSize.Empty;
 			_originalCGImage = null;
 		}
+
+		private static void MapFormatting(IButtonHandler handler, IText button)
+		{
+			// Update all of the attributed text formatting properties
+			handler.PlatformView?.UpdateCharacterSpacing(button);
+		}
 	}
 }

src/Controls/src/Core/Platform/iOS/Extensions/ButtonExtensions.cs

@@ -86,12 +86,7 @@ public static void UpdateText(this UIButton platformButton, Button button)
 		{
 			var text = TextTransformUtilites.GetTransformedText(button.Text, button.TextTransform);
 			platformButton.SetTitle(text, UIControlState.Normal);
-
-			// The TitleLabel retains its previous text value even after a new value is assigned. As a result, the label does not display the updated text and reverts to the old value when the button is re-measured
-			if (string.IsNullOrEmpty(button.Text))
-			{
-				platformButton.TitleLabel.Text = string.Empty;
-			}
+			platformButton.TitleLabel.Text = button.Text;
 
 			// Content layout depends on whether or not the text is empty; changing the text means
 			// we may need to update the content layout

src/Controls/tests/TestCases.HostApp/Issues/Issue21488.cs

@@ -0,0 +1,27 @@
+namespace Maui.Controls.Sample.Issues;
+
+[XamlCompilation(XamlCompilationOptions.Compile)]
+[Issue(IssueTracker.Github, "21488", "Button text doesn't update when CharacterSpacing is applied", PlatformAffected.iOS)]
+public partial class Issue21488 : ContentPage
+{
+	public Issue21488()
+	{
+		var buttonWithoutCharacterSpacing = new Button();
+		var buttonWithCharacterSpacing = new Button() { CharacterSpacing = 15 };
+		var entry = new Entry() { AutomationId = "Entry" };
+		entry.TextChanged += (s, e) =>
+		{
+			buttonWithoutCharacterSpacing.Text = entry.Text;
+			buttonWithCharacterSpacing.Text = entry.Text;
+		};
+
+		Content = new VerticalStackLayout()
+		{
+			new Label() { Text = "Button without character spacing:" },
+			buttonWithoutCharacterSpacing,
+			new Label() { Text = "Button with character spacing:" },
+			buttonWithCharacterSpacing,
+			entry
+		};
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue21488.cs

@@ -0,0 +1,24 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue21488 : _IssuesUITest
+	{
+		public Issue21488(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "Button text doesn't update when CharacterSpacing is applied";
+
+		[Test]
+		[Category(UITestCategories.Button)]
+		public void ButtonTextShouldUpdate()
+		{
+			App.WaitForElement("Entry");
+			App.EnterText("Entry", "Hello, Maui!");
+			VerifyScreenshot();
+		}
+	}
+}