Merge pull request #58 from egvijayanand/working

Sample project to demonstrate C# Hot Reload

README.md

@@ -25,6 +25,7 @@ Available under the `src` directory:
   - Both Xamarin.Forms and .NET MAUI from a single project - `DateCalculator.UI`
 * `EmbeddedAndroid` - .NET MAUI Page embedded in a Native Android App, targeting .NET 6 (`net6.0-android`)
 * `MediaElement` - Sample project in both .NET 6 and 7. Now made available in Preview bits as part of the .NET MAUI CommunityToolkit - And it'll be a separate NuGet package titled `CommunityToolkit.Maui.MediaElement`
+* `MauiHotReload` - Sample project to demonstrate **C# Hot Reload** feature supported via [MetadataUpdateHandler](https://learn.microsoft.com/en-us/dotnet/api/system.reflection.metadata.metadataupdatehandlerattribute?view=net-6.0) (refer to HotReloadService.cs). Core logic is abstracted into a base page named `MauiPage`, inherit the content pages from it and implement the UI logic in the override of the abstract `Build()` method. Source is available in the `src\MauiHotReload` folder.
 
 * C# Samples - C# version of the [.NET MAUI UI Challenge](https://aka.ms/maui/UIChallenge) - [Awesome UIs](https://github.com/jsuarezruiz/dotnet-maui-showcase) without any XAML usage - Stay tuned for more samples ...
   - Made available under the `src/C#-Samples/` folder

src/MauiHotReload/App.cs

@@ -0,0 +1,71 @@
+using System.Reflection;
+
+namespace MauiHotReload
+{
+	public partial class App : Application
+	{
+		public App()
+		{
+			Initialize();
+
+			MainPage = new NavigationPage(new HomePage());
+		}
+
+		private void Initialize()
+		{
+			var assembly = GetType().Assembly;
+			Resources.MergedDictionaries.Add(GetXamlResourceDictionary("Resources/Colors.xaml", assembly));
+			Resources.MergedDictionaries.Add(GetXamlResourceDictionary("Resources/Styles.xaml", assembly));
+			Resources.Add("ApplePadding", new Thickness(30, 60, 30, 30));
+			Resources.Add("DefaultPadding", new Thickness(30));
+			Resources.Add("ItemSpacing", 10d);
+			Resources.Add(new Style(typeof(StackBase))
+			{
+				ApplyToDerivedTypes = true,
+				Setters =
+				{
+					new() { Property = StackBase.SpacingProperty, Value = AppResource<double>("ItemSpacing") },
+				},
+			});
+			Resources.Add(new Style(typeof(ContentPage))
+			{
+				ApplyToDerivedTypes = true,
+				Setters =
+				{
+					new() { Property = Page.PaddingProperty, Value = DeviceInfo.Idiom.ToString() switch { nameof(DeviceIdiom.Phone) => AppResource<Thickness>("ApplePadding"), _ => AppResource<Thickness>("DefaultPadding") } },
+				},
+			});
+			Resources.Add("MauiLabel", new Style(typeof(Label))
+			{
+				Setters =
+				{
+					new() { Property = Label.TextColorProperty, Value = RequestedTheme switch { AppTheme.Dark => AppResource<Color>("White"), AppTheme.Light or _ => AppResource<Color>("Primary") } },
+				},
+			});
+			Resources.Add("Action", new Style(typeof(Button))
+			{
+				Setters =
+				{
+					new() { Property = Button.BackgroundColorProperty, Value = RequestedTheme switch { AppTheme.Dark => AppResource<Color>("BackgroundDark"), AppTheme.Light or _ => AppResource<Color>("BackgroundLight") } },
+					new() { Property = Button.TextColorProperty, Value = RequestedTheme switch { AppTheme.Dark => AppResource<Color>("TextDark"), AppTheme.Light or _ => AppResource<Color>("TextLight") } },
+					new() { Property = Button.FontFamilyProperty, Value = AppResource<string>("AppFont") },
+					new() { Property = Button.FontSizeProperty, Value = AppResource<double>("AppFontSize") },
+					new() { Property = Button.PaddingProperty, Value = new Thickness(14,10) },
+				},
+			});
+			Resources.Add("PrimaryAction", new Style(typeof(Button))
+			{
+				BasedOn = AppResource<Style>("Action"),
+				Setters =
+				{
+					new() { Property = Button.BackgroundColorProperty, Value = AppResource<Color>("Primary") },
+					new() { Property = Button.FontAttributesProperty, Value = FontAttributes.Bold },
+					new() { Property = Button.TextColorProperty, Value = AppResource<Color>("White") },
+				},
+			});
+		}
+
+		private static ResourceDictionary GetXamlResourceDictionary(string resourcePath, Assembly assembly)
+			=> GetXamlResource<ResourceDictionary>(resourcePath, assembly);
+	}
+}

src/MauiHotReload/DetailsPage.cs

@@ -0,0 +1,20 @@
+namespace MauiHotReload
+{
+	public class DetailsPage : MauiPage
+	{
+		protected override void Build()
+		{
+			Title = "Details";
+			Content = new Grid()
+			{
+				Children =
+				{
+					new Label()
+					{
+						Text = "Details Page"
+					}.Center()
+				}
+			};
+		}
+	}
+}

src/MauiHotReload/HomePage.cs

@@ -0,0 +1,44 @@
+namespace MauiHotReload
+{
+	public class HomePage : MauiPage
+	{
+		protected override void Build()
+		{
+			Title = "Home";
+			Content = new Grid
+			{
+				RowDefinitions = Rows.Define(Star, Star, Star, Star),
+				ColumnDefinitions = Columns.Define(Star, Star),
+				Children =
+				{
+					new Label
+					{
+						Text = "Landing Page",
+					}.Row(0).ColumnSpan(2).Center(),
+					new Label
+					{
+						Text = "Hot reloaded label in row 2 spanning two columns",
+					}.Row(1).ColumnSpan(2).Center(),
+					new Button
+					{
+						Text = "Go to details",
+						Style = AppResource<Style>("PrimaryAction"),
+					}.Row(2).Column(0).Center().Invoke(btn => btn.Clicked += OnClicked),
+					new Label
+					{
+						Text = "Hot reloaded label in row 3 column 2 with text aligned at the end",
+					}.Row(2).Column(1).End().CenterVertical(),
+					new Label
+					{
+						Text = "Hot reloaded label in row 4 spanning two columns",
+					}.Row(3).ColumnSpan(2).Center()
+				}
+			};
+		}
+
+		private async void OnClicked(object? sender, EventArgs e)
+		{
+			await Navigation.PushAsync(new DetailsPage());
+		}
+	}
+}

src/MauiHotReload/HotReloadService.cs

@@ -0,0 +1,20 @@
+#if DEBUG
+using System.Reflection.Metadata;
+
+[assembly: MetadataUpdateHandler(typeof(MauiHotReload.HotReloadService))]
+
+namespace MauiHotReload
+{
+	public static class HotReloadService
+	{
+		//#pragma warning disable CS8632 // The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.
+		public static event Action<Type[]?>? UpdateApplicationEvent;
+		//#pragma warning restore CS8632 // The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.
+
+		internal static void ClearCache(Type[]? types) { }
+
+		internal static void UpdateApplication(Type[]? types)
+			=> UpdateApplicationEvent?.Invoke(types);
+	}
+}
+#endif

src/MauiHotReload/Imports.cs

@@ -0,0 +1,6 @@
+// Markup
+global using CommunityToolkit.Maui.Markup;
+// Static
+global using static CommunityToolkit.Maui.Markup.GridRowsColumns;
+global using static Microsoft.Maui.Graphics.Colors;
+global using static VijayAnand.Toolkit.Markup.ResourceHelper;

src/MauiHotReload/MauiHotReload.code-workspace

@@ -0,0 +1,15 @@
+{
+    "folders": [
+        {
+            "path": "."
+        }
+    ],
+    "settings": {},
+    "extensions": {
+        "recommendations": [
+            "ms-dotnettools.csharp",
+            "clancey.comet-debug",
+            "VisualStudioExptTeam.vscodeintellicode"
+        ]
+    }
+}

src/MauiHotReload/MauiHotReload.csproj

@@ -0,0 +1,64 @@
+<Project Sdk="Microsoft.NET.Sdk">
+	<PropertyGroup>
+		<TargetFrameworks>net6.0-android;net6.0-ios;net6.0-maccatalyst</TargetFrameworks>
+		<!-- Targets possible from Windows OS -->
+		<TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">$(TargetFrameworks);net6.0-windows10.0.19041.0</TargetFrameworks>
+		<!-- Uncomment to also build the Tizen app. You will need to install Tizen by following this: https://github.com/Samsung/Tizen.NET -->
+		<!-- <TargetFrameworks>$(TargetFrameworks);net6.0-tizen</TargetFrameworks> -->
+		<OutputType>Exe</OutputType>
+
+		<!-- .NET MAUI -->
+		<UseMaui>true</UseMaui>
+		<SingleProject>true</SingleProject>
+
+		<!-- Project Options -->
+		<Nullable>enable</Nullable>
+		<ImplicitUsings>enable</ImplicitUsings>
+		<RootNamespace>MauiHotReload</RootNamespace>
+
+		<!-- Display name -->
+		<ApplicationTitle>MauiHotReload</ApplicationTitle>
+
+		<!-- App Identifier -->
+		<ApplicationId>com.companyname.mauihotreload</ApplicationId>
+		<ApplicationIdGuid>080d8082-5270-4fd1-bfe9-7b5143f53696</ApplicationIdGuid>
+
+		<!-- Versions -->
+		<ApplicationDisplayVersion>1.0</ApplicationDisplayVersion>
+		<ApplicationVersion>1</ApplicationVersion>
+
+		<!-- Target Platform Options -->
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios'">14.2</SupportedOSPlatformVersion>
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'maccatalyst'">14.0</SupportedOSPlatformVersion>
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'android'">21.0</SupportedOSPlatformVersion>
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">10.0.17763.0</SupportedOSPlatformVersion>
+		<SupportedOSPlatformVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'tizen'">6.5</SupportedOSPlatformVersion>
+
+		<!-- Minimum Target OS Version for Windows Platform -->
+		<TargetPlatformMinVersion Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'windows'">10.0.17763.0</TargetPlatformMinVersion>
+	</PropertyGroup>
+
+	<ItemGroup>
+		<!-- App Icon -->
+		<MauiIcon Include="Resources\appicon.svg" ForegroundFile="Resources\appiconfg.svg" Color="#512BD4" />
+		<!-- Splash Screen -->
+		<MauiSplashScreen Include="Resources\appiconfg.svg" Color="#512BD4" BaseSize="128,128" />
+		<!-- Images -->
+		<MauiImage Include="Resources\Images\*" />
+		<MauiImage Update="Resources\Images\dotnet_bot.svg" BaseSize="168,208" />
+		<!-- Custom Fonts -->
+		<MauiFont Include="Resources\Fonts\*" />
+		<!-- Raw Assets (also remove the "Resources\Raw" prefix) -->
+		<MauiAsset Include="Resources\Raw\**" LogicalName="%(RecursiveDir)%(Filename)%(Extension)" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<None Remove="MauiHotReload.code-workspace" />
+	</ItemGroup>
+
+	<ItemGroup>
+		<PackageReference Include="CommunityToolkit.Maui.Markup" Version="1.2.0" />
+		<PackageReference Include="VijayAnand.Toolkit.Markup" Version="1.0.1-pre1" />
+	</ItemGroup>
+
+</Project>

src/MauiHotReload/MauiHotReload.sln

@@ -0,0 +1,28 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.31611.283
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MauiHotReload", "MauiHotReload.csproj", "{579DBAEF-3844-4DAC-B61D-A26EA353C2C3}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{579DBAEF-3844-4DAC-B61D-A26EA353C2C3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{579DBAEF-3844-4DAC-B61D-A26EA353C2C3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{579DBAEF-3844-4DAC-B61D-A26EA353C2C3}.Debug|Any CPU.Deploy.0 = Debug|Any CPU
+		{579DBAEF-3844-4DAC-B61D-A26EA353C2C3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{579DBAEF-3844-4DAC-B61D-A26EA353C2C3}.Release|Any CPU.Build.0 = Release|Any CPU
+		{579DBAEF-3844-4DAC-B61D-A26EA353C2C3}.Release|Any CPU.Deploy.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		        SolutionGuid = {61F7FB11-1E47-470C-91E2-47F8143E1572}
+		SolutionGuid = {EC2EA614-E633-4058-8E91-AE765501F5FB}
+	EndGlobalSection
+EndGlobal

src/MauiHotReload/MauiPage.cs

@@ -0,0 +1,47 @@
+namespace MauiHotReload
+{
+	public abstract class MauiPage : ContentPage
+	{
+		public MauiPage()
+		{
+			Build();
+#if DEBUG
+			if (Application.Current is not null)
+			{
+				// Not a NavigationPage / TabbedPage / Shell
+				if (Application.Current.MainPage is ContentPage)
+				{
+					HotReloadService.UpdateApplicationEvent += Refresh;
+				}
+			}
+#endif
+		}
+
+		protected abstract void Build();
+
+		protected override void OnNavigatedTo(NavigatedToEventArgs args)
+		{
+			base.OnNavigatedTo(args);
+#if DEBUG
+			HotReloadService.UpdateApplicationEvent += Refresh;
+#endif
+		}
+
+		protected override void OnNavigatedFrom(NavigatedFromEventArgs args)
+		{
+			base.OnNavigatedFrom(args);
+#if DEBUG
+			HotReloadService.UpdateApplicationEvent -= Refresh;
+#endif
+		}
+
+		private void Refresh(Type[]? obj) => Dispatcher.Dispatch(Build);
+
+		public void Dispose()
+		{
+#if DEBUG
+			HotReloadService.UpdateApplicationEvent -= Refresh;
+#endif
+		}
+	}
+}

src/MauiHotReload/MauiProgram.cs

@@ -0,0 +1,19 @@
+namespace MauiHotReload
+{
+	public static class MauiProgram
+	{
+		public static MauiApp CreateMauiApp()
+		{
+			var builder = MauiApp.CreateBuilder();
+			builder.UseMauiApp<App>()
+				   .UseMauiCommunityToolkitMarkup()
+				   .ConfigureFonts(fonts =>
+				   {
+					   fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
+					   fonts.AddFont("OpenSans-SemiBold.ttf", "OpenSansSemiBold");
+				   });
+
+			return builder.Build();
+		}
+	}
+}

src/MauiHotReload/Platforms/Android/AndroidManifest.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="31" />
+    <application android:allowBackup="true" android:icon="@mipmap/appicon" android:roundIcon="@mipmap/appicon_round" android:supportsRtl="true"></application>
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+</manifest>

src/MauiHotReload/Platforms/Android/MainActivity.cs

@@ -0,0 +1,12 @@
+using Android.App;
+using Android.Content.PM;
+using Android.OS;
+
+namespace MauiHotReload
+{
+    [Activity(Theme = "@style/Maui.SplashTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize)]
+    public class MainActivity : MauiAppCompatActivity
+    {
+
+    }
+}

src/MauiHotReload/Platforms/Android/MainApplication.cs

@@ -0,0 +1,16 @@
+using Android.App;
+using Android.Runtime;
+
+namespace MauiHotReload
+{
+    [Application]
+    public class MainApplication : MauiApplication
+    {
+        public MainApplication(IntPtr handle, JniHandleOwnership ownership)
+            : base(handle, ownership)
+        {
+        }
+
+        protected override MauiApp CreateMauiApp() => MauiProgram.CreateMauiApp();
+    }
+}

src/MauiHotReload/Platforms/Android/Resources/values/colors.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<resources>
+    <color name="colorPrimary">#512BD4</color>
+    <color name="colorPrimaryDark">#2B0B98</color>
+    <color name="colorAccent">#2B0B98</color>
+</resources>