feat: HR support for LoadingView

samples/Directory.Packages.props

@@ -5,5 +5,6 @@
 	<ItemGroup>
 		<PackageVersion Include="Uno.Core.Extensions.Compatibility" Version="4.0.1" />
 		<PackageVersion Include="Xamarin.TestCloud.Agent" Version="0.23.2" />
+		<PackageVersion Include="Uno.WinUI.DevServer" Version="6.2.58" />
 	</ItemGroup>
 </Project>

samples/Uno.Toolkit.Samples/Uno.Toolkit.Samples/Uno.Toolkit.Samples.csproj

@@ -58,6 +58,7 @@
 
 	<ItemGroup>
 		<PackageReference Include="Uno.Core.Extensions.Compatibility" />
+		<PackageReference Include="Uno.WinUI.DevServer" />
 	</ItemGroup>
 
 	<ItemGroup Condition="('$(Configuration)'=='Debug' or '$(IsUiAutomationMappingEnabled)'=='True') and $(IsIOS) and !$(RuntimeIdentifier.Contains('arm64'))">

src/Directory.Packages.props

@@ -36,9 +36,10 @@
     <PackageVersion Include="Uno.UITest.Helpers" Version="1.1.0-dev.82" />
     <PackageVersion Include="Uno.UITest.Selenium" Version="1.1.0-dev.82" />
     <PackageVersion Include="Uno.UITest.Xamarin" Version="1.1.0-dev.82" />
-    <PackageVersion Include="Xamarin.AndroidX.Core.SplashScreen" Version="1.0.1.6" />
+    <PackageVersion Include="Uno.WinUI.DevServer" Version="6.2.58" />
+	  <PackageVersion Include="Xamarin.AndroidX.Core.SplashScreen" Version="1.0.1.6" />
     <PackageVersion Include="Xamarin.UITest" Version="4.4.0" />
     <PackageVersion Include="MSTest.TestFramework" Version="2.1.2" />
     <PackageVersion Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="8.0.0" />
   </ItemGroup>
-</Project>
+</Project>

src/Uno.Toolkit.RuntimeTests/Tests/HotReload/LoadingViewHRTest.cs

@@ -0,0 +1,65 @@
+using FluentAssertions;
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Uno.Toolkit.RuntimeTests.Tests.TestPages;
+using Uno.Toolkit.UI;
+using Uno.UI.RuntimeTests;
+using Windows.Foundation;
+
+namespace Uno.Toolkit.RuntimeTests.Tests.HotReload
+{
+	// Keep ignored in CI; run locally in Debug without a debugger attached.
+	// Temporarily disabled: Sample app auto-exits and test fails.
+	//Tracking with https://github.com/unoplatform/uno.toolkit.ui/issues/1480
+	[Ignore]
+	[TestClass]
+	[RunsInSecondaryApp(ignoreIfNotSupported: true)]
+	public class LoadingViewHrTest
+	{
+		[TestMethod]
+		public async Task HR_keeps_Loaded_state_by_preserving_Source(CancellationToken ct)
+		{
+			await UIHelper.Load(new LoadingViewPage(), ct);
+
+			var lv = UIHelper.GetChild<LoadingView>(name: "LV");
+			var marker = UIHelper.GetChild<TextBlock>(name: "Marker");
+
+			lv.Source = new TestLoadable(isExecuting: false);
+
+			lv.Content = new Border();
+
+			Assert.IsNotNull(lv.Source);
+			Assert.IsFalse(lv.Source!.IsExecuting);
+			Assert.AreEqual("Original marker", marker.Text);
+
+			await using (await HotReloadHelper.UpdateSourceFile<LoadingViewPage>(originalText: "Original marker", replacementText: "Updated marker", ct))
+			{
+				await TestHelper.WaitFor(() =>
+					UIHelper.GetChild<TextBlock>(name: "Marker").Text == "Updated marker", ct);
+			}
+
+			var lvAfter = UIHelper.GetChild<LoadingView>(name: "LV");
+
+			Assert.IsNotNull(lvAfter.Source);
+			Assert.IsFalse(lvAfter.Source.IsExecuting);
+
+			Assert.IsNotNull(lvAfter.Content);
+		}
+	}
+
+	internal sealed class TestLoadable(bool isExecuting = false) : ILoadable
+	{
+		public event EventHandler? IsExecutingChanged;
+
+		bool _isExecuting = isExecuting;
+		public bool IsExecuting
+		{
+			get => _isExecuting;
+			set { if (_isExecuting != value) { _isExecuting = value; IsExecutingChanged?.Invoke(this, EventArgs.Empty); } }
+		}
+	}
+}

src/Uno.Toolkit.RuntimeTests/Tests/TestPages/LoadingViewPage.xaml

@@ -0,0 +1,24 @@
+<Page
+	x:Class="Uno.Toolkit.RuntimeTests.Tests.TestPages.LoadingViewPage"
+	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+	xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+	xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+	xmlns:local="using:Uno.Toolkit.RuntimeTests.Tests.TestPages"
+	xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+	xmlns:utu="using:Uno.Toolkit.UI"
+	Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
+	Tag="Page Tag"
+	mc:Ignorable="d">
+
+	<Grid Padding="12">
+		<TextBlock
+			x:Name="Marker"
+			Margin="0,0,0,12"
+			Text="Original marker" />
+		<utu:LoadingView x:Name="LV">
+			<utu:LoadingView.LoadingContent>
+				<TextBlock Text="Loading…" />
+			</utu:LoadingView.LoadingContent>
+		</utu:LoadingView>
+	</Grid>
+</Page>

src/Uno.Toolkit.RuntimeTests/Tests/TestPages/LoadingViewPage.xaml.cs

@@ -0,0 +1,10 @@
+namespace Uno.Toolkit.RuntimeTests.Tests.TestPages
+{
+	public sealed partial class LoadingViewPage : Page
+	{
+		public LoadingViewPage()
+		{
+			this.InitializeComponent();
+		}
+	}
+}

src/Uno.Toolkit.RuntimeTests/Uno.Toolkit.RuntimeTests.csproj

@@ -40,7 +40,8 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Uno.UI.RuntimeTests.Engine" />
-    <PackageReference Include="MSTest.TestFramework" />
+    <PackageReference Include="Uno.WinUI.DevServer" />
+		<PackageReference Include="MSTest.TestFramework" />
     <PackageReference Include="FluentAssertions" />
   </ItemGroup>
   <ItemGroup>

src/Uno.Toolkit.UI/Controls/LoadingView/LoadingView.HotReload.cs

@@ -0,0 +1,44 @@
+#if IS_WINUI
+using System;
+using System.Collections.Generic;
+using System.Reflection.Metadata;
+using System.Threading.Tasks;
+using Microsoft.UI.Xaml;
+using Uno.Toolkit.UI;
+
+[assembly: ElementMetadataUpdateHandlerAttribute(typeof(LoadingView), typeof(LoadingViewElementMetadataUpdateHandler))]
+
+namespace Uno.Toolkit.UI;
+
+internal static class LoadingViewElementMetadataUpdateHandler
+{
+	private const string SourceKey = nameof(LoadingView) + "." + nameof(LoadingView.Source);
+	private const string ContentKey = nameof(LoadingView) + "." + nameof(LoadingView.Content);
+
+	public static void CaptureState(FrameworkElement element, IDictionary<string, object> stateDictionary, Type[]? updatedTypes)
+	{
+		if (element is LoadingView lv)
+		{
+			stateDictionary[SourceKey] = lv.Source;
+			stateDictionary[ContentKey] = lv.Content;
+		}
+	}
+
+	public static Task RestoreState(FrameworkElement element, IDictionary<string, object> state, Type[]? updatedTypes)
+	{
+		if (element is LoadingView lv)
+		{
+			if (lv.Source is null && lv.GetBindingExpression(LoadingView.SourceProperty) is null && state.TryGetValue(SourceKey, out var savedSrc) && savedSrc is ILoadable src)
+			{
+				lv.Source = src;
+			}
+			if (lv.Content is null && lv.GetBindingExpression(LoadingView.ContentProperty) is null && state.TryGetValue(ContentKey, out var savedContent) && savedContent is { } content)
+			{
+				lv.Content = content;
+			}
+		}
+
+		return Task.CompletedTask;
+	}
+}
+#endif