Global Navigation Observer

Directory.Build.props

@@ -16,9 +16,11 @@
     <PrismLicenseFile>$(MSBuildThisFileDirectory)LICENSE</PrismLicenseFile>
     <PackageTags>prism;maui;dotnet-maui;xaml;mvvm;ios;android;mac;winui</PackageTags>
     <Copyright>Copyright Dan Siegel 2021</Copyright>
-    <Description>This is a special preview package. In order to use this be sure that you have installed the Maui workload with Visual Studio 2022 preview 4 or later. Alternatively you may use Maui-Check to ensure that your environment has the required prerequesites to build from the command line with Visual Studio Code.
+    <Description>
+      Prism is a fully open source version of the Prism guidance originally produced by Microsoft Patterns &amp; Practices. Prism provides an implementation of a collection of design patterns that are helpful in writing well structured, maintainable, and testable XAML applications, including MVVM, dependency injection, commanding, event aggregation, and more. Prism's core functionality is a shared library targeting the .NET Framework and .NET Standard. Features that need to be platform specific are implemented in the respective libraries for the target platform (WPF, Uno Platform, Xamarin Forms, and .NET MAUI).
 
-As this is special preview build there are no docs, be sure to check out the source repo at: https://github.com/dansiegel/prism.maui </Description>
+      Prism for .NET MAUI helps you more easily design and build rich, flexible, and easy to maintain .NET MAUI applications. This library provides user interface composition as well as modularity support.
+    </Description>
 <!-- HACK: WinUI seems to have issues without this -->
     <GenerateLibraryLayout>true</GenerateLibraryLayout>
     <DisableEmbeddedXbf>false</DisableEmbeddedXbf>
@@ -38,7 +40,7 @@ As this is special preview build there are no docs, be sure to check out the sou
 
   <ItemGroup>
     <PackageReference Include="Nerdbank.GitVersioning" 
-                      Version="3.5.104"
+                      Version="3.5.107"
                       PrivateAssets="all" />
     <PackageReference Include="Microsoft.SourceLink.GitHub"
                       Version="1.1.1"

Prism.Maui.sln

@@ -9,7 +9,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{6CAB3327-8C0
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Prism.DryIoc.Maui", "src\Prism.DryIoc.Maui\Prism.DryIoc.Maui.csproj", "{6C5C1F1F-DA92-4307-862F-5034BF8B0858}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Prism.Maui", "src\Prism.Maui\Prism.Maui.csproj", "{6171FE41-1F11-4CFA-8FD8-8222B97C7C63}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Prism.Maui", "src\Prism.Maui\Prism.Maui.csproj", "{6171FE41-1F11-4CFA-8FD8-8222B97C7C63}"
 EndProject
 Project("{D954291E-2A0B-460D-934E-DC6B0785DB48}") = "Prism.DryIoc.Shared", "src\Prism.DryIoc.Shared\Prism.DryIoc.Shared.shproj", "{6E7EC81D-DA39-4C4F-A898-0148558C34F4}"
 EndProject
@@ -30,6 +30,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MauiModule", "sample\MauiModule\MauiModule.csproj", "{EB8CD219-0CA7-4AE3-A7B7-6D883400CCE0}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Prism.Maui.Rx", "src\Prism.Maui.Rx\Prism.Maui.Rx.csproj", "{D364B3F0-2D41-4EF8-BE1D-D83825322F61}"
+EndProject
 Global
 	GlobalSection(SharedMSBuildProjectFiles) = preSolution
 		src\Prism.DryIoc.Shared\Prism.DryIoc.Shared.projitems*{6c5c1f1f-da92-4307-862f-5034bf8b0858}*SharedItemsImports = 5
@@ -127,6 +129,22 @@ Global
 		{EB8CD219-0CA7-4AE3-A7B7-6D883400CCE0}.Release|x64.Build.0 = Release|Any CPU
 		{EB8CD219-0CA7-4AE3-A7B7-6D883400CCE0}.Release|x86.ActiveCfg = Release|Any CPU
 		{EB8CD219-0CA7-4AE3-A7B7-6D883400CCE0}.Release|x86.Build.0 = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|arm64.ActiveCfg = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|arm64.Build.0 = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|x64.Build.0 = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Debug|x86.Build.0 = Debug|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|arm64.ActiveCfg = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|arm64.Build.0 = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|x64.ActiveCfg = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|x64.Build.0 = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|x86.ActiveCfg = Release|Any CPU
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -138,6 +156,7 @@ Global
 		{3BFAB205-050B-47B7-9AB8-BE799E07DA90} = {7CB47440-CCBC-4E16-B2B9-9FD472154117}
 		{16AEEF3D-B119-4EE0-9B1F-B9E0FDF0EEAB} = {06F06128-578F-449D-B3D6-D04A531B1018}
 		{EB8CD219-0CA7-4AE3-A7B7-6D883400CCE0} = {06F06128-578F-449D-B3D6-D04A531B1018}
+		{D364B3F0-2D41-4EF8-BE1D-D83825322F61} = {6CAB3327-8C0A-4D0B-BF18-CEFD15B84BA7}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {7E696A15-8B47-4BC2-8997-071E61157406}

sample/PrismMauiDemo/MauiProgram.cs

@@ -16,10 +16,21 @@ public static MauiApp CreateMauiApp()
             })
             .RegisterTypes(containerRegistry =>
             {
+                containerRegistry.RegisterGlobalNavigationObserver();
                 containerRegistry.RegisterForNavigation<MainPage>();
                 containerRegistry.RegisterForNavigation<RootPage>();
                 containerRegistry.RegisterForNavigation<SamplePage>();
             })
+            .AddGlobalNavigationObserver(context => context.Subscribe(x =>
+            {
+                if (x.Type == NavigationRequestType.Navigate)
+                    Console.WriteLine($"Navigation: {x.Type} - {x.Uri}");
+                else
+                    Console.WriteLine($"Navigation: {x.Type}");
+
+                var status = x.Cancelled ? "Cancelled" : x.Result.Success ? "Success" : "Failed";
+                Console.WriteLine($"Result: {status}");
+            }))
             .OnAppStart(navigationService => navigationService.CreateBuilder()
                 .AddNavigationSegment("MainPage")
                 .AddNavigationPage()

sample/PrismMauiDemo/PrismMauiDemo.csproj

@@ -51,6 +51,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Prism.DryIoc.Maui\Prism.DryIoc.Maui.csproj" />
+    <ProjectReference Include="..\..\src\Prism.Maui.Rx\Prism.Maui.Rx.csproj" />
     <ProjectReference Include="..\..\src\Prism.Maui\Prism.Maui.csproj" />
     <ProjectReference Include="..\MauiModule\MauiModule.csproj" />
   </ItemGroup>

src/Prism.DryIoc.Maui/Prism.DryIoc.Maui.csproj

@@ -5,6 +5,7 @@
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <UseMaui>true</UseMaui>
     <ImplicitUsings>true</ImplicitUsings>
+    <Description>Prism.DryIoc.Maui provides the implementation of Prism's IContainerExtension using the DryIoc container. This is currently the only supported container for .NET MAUI.</Description>
   </PropertyGroup>
 
   <ItemGroup>

src/Prism.Maui.Rx/GlobalNavigationObserver.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Reactive.Subjects;
+using Prism.Events;
+
+namespace Prism.Navigation;
+
+internal class GlobalNavigationObserver : IGlobalNavigationObserver, IDisposable
+{
+    private readonly Subject<NavigationRequestContext> _subject;
+    private SubscriptionToken _token;
+
+    public GlobalNavigationObserver(IEventAggregator eventAggregator)
+    {
+        _subject = new Subject<NavigationRequestContext>();
+        _token = eventAggregator.GetEvent<NavigationRequestEvent>().Subscribe(context => _subject.OnNext(context));
+    }
+
+    public IObservable<NavigationRequestContext> NavigationRequest => _subject;
+
+    public void Dispose()
+    {
+        if (_token is null)
+            return;
+
+        _token.Dispose();
+        _token = null;
+        _subject.Dispose();
+    }
+}

src/Prism.Maui.Rx/IGlobalNavigationObserver.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace Prism.Navigation;
+
+public interface IGlobalNavigationObserver
+{
+    IObservable<NavigationRequestContext> NavigationRequest { get; }
+}

src/Prism.Maui.Rx/NavigationObserverRegistrationExtensions.cs

@@ -0,0 +1,45 @@
+using Microsoft.Extensions.DependencyInjection;
+using Prism.Ioc;
+
+namespace Prism.Navigation;
+
+public static class NavigationObserverRegistrationExtensions
+{
+    private static bool s_IsRegistered;
+
+    public static IContainerRegistry RegisterGlobalNavigationObserver(this IContainerRegistry container)
+    {
+        if (s_IsRegistered)
+            return container;
+
+        s_IsRegistered = true;
+        return container.RegisterSingleton<IGlobalNavigationObserver, GlobalNavigationObserver>();
+    }
+
+    public static IServiceCollection RegisterGlobalNavigationObserver(this IServiceCollection services)
+    {
+        if (s_IsRegistered)
+            return services;
+
+        s_IsRegistered = true;
+        return services.AddSingleton<IGlobalNavigationObserver, GlobalNavigationObserver>();
+    }
+
+    public static PrismAppBuilder AddGlobalNavigationObserver(this PrismAppBuilder builder, Action<IObservable<NavigationRequestContext>> addObservable) =>
+        builder.OnInitialized(c =>
+        {
+            if (!s_IsRegistered)
+                throw new Exception("IGlobalNavigationObserver has not been registered. Be sure to call 'container.RegisterGlobalNavigationObserver()'.");
+
+            addObservable(c.Resolve<IGlobalNavigationObserver>().NavigationRequest);
+        });
+
+    public static PrismAppBuilder AddGlobalNavigationObserver(this PrismAppBuilder builder, Action<IContainerProvider, IObservable<NavigationRequestContext>> addObservable) =>
+        builder.OnInitialized(c =>
+        {
+            if (!s_IsRegistered)
+                throw new Exception("IGlobalNavigationObserver has not been registered. Be sure to call 'container.RegisterGlobalNavigationObserver()'.");
+
+            addObservable(c, c.Resolve<IGlobalNavigationObserver>().NavigationRequest);
+        });
+}

src/Prism.Maui.Rx/Prism.Maui.Rx.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>true</ImplicitUsings>
+    <Description>Prism.Maui.Rx is a support package for .NET MAUI developers. This package provides some helpers to access an IObservable for globally handling Navigation Request Results.</Description>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Prism.Maui\Prism.Maui.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="System.Reactive" Version="5.0.0" />
+  </ItemGroup>
+
+</Project>

src/Prism.Maui/Behaviors/NavigationPageSystemGoBackBehavior.cs

@@ -21,6 +21,7 @@ private void NavigationPage_Popped(object sender, NavigationEventArgs e)
     {
         if (PageNavigationService.NavigationSource == PageNavigationSource.Device)
         {
+            System.Diagnostics.Trace.WriteLine("NavigationPage has encountered an unhandled GoBack. Be sure to inherit from PrismNavigationPage.");
             PageUtilities.HandleSystemGoBack(e.Page, AssociatedObject.CurrentPage);
         }
     }

src/Prism.Maui/Common/PageUtilities.cs

@@ -229,19 +229,8 @@ public static void SetCurrentPageDelegate(Func<Page, Page> getCurrentPageDelegat
 
     public static async Task HandleNavigationPageGoBack(NavigationPage navigationPage)
     {
-        var previousPage = navigationPage.CurrentPage;
-        var parameters = new NavigationParameters();
-        parameters.GetNavigationParametersInternal().Add(KnownInternalParameters.NavigationMode, NavigationMode.Back);
-        if (!CanNavigate(previousPage, parameters) ||
-            !await CanNavigateAsync(previousPage, parameters))
-            return;
-
-        PageNavigationService.NavigationSource = PageNavigationSource.NavigationService;
-        await navigationPage.PopAsync();
-        PageNavigationService.NavigationSource = PageNavigationSource.Device;
-        OnNavigatedFrom(previousPage, parameters);
-        OnNavigatedTo(navigationPage.CurrentPage, parameters);
-        DestroyPage(previousPage);
+        var navigationService = Navigation.Xaml.Navigation.GetNavigationService(navigationPage.CurrentPage);
+        await navigationService.GoBackAsync();
     }
 
     public static void HandleSystemGoBack(IView previousPage, IView currentPage)

src/Prism.Maui/Events/NavigationRequestEvent.cs

@@ -0,0 +1,8 @@
+using Prism.Navigation;
+
+namespace Prism.Events;
+
+public class NavigationRequestEvent : PubSubEvent<NavigationRequestContext>
+{
+}
+

src/Prism.Maui/Navigation/KnownNavigationParameters.cs

@@ -17,6 +17,11 @@ public static class KnownNavigationParameters
     /// </summary>
     public const string UseModalNavigation = "useModalNavigation";
 
+    /// <summary>
+    /// Used to control whether the navigation should be animated.
+    /// </summary>
+    public const string Animated = "animated";
+
     /// <summary>
     /// Used to define a navigation parameter that is bound directly to a CommandParameter via <code>{Binding .}</code>.
     /// </summary>

src/Prism.Maui/Navigation/NavigationRequestContext.cs

@@ -0,0 +1,10 @@
+namespace Prism.Navigation;
+
+public record NavigationRequestContext
+{
+    public bool Cancelled => Result?.Exception is not null && Result.Exception is NavigationException ne && ne.Message == NavigationException.IConfirmNavigationReturnedFalse;
+    public NavigationRequestType Type { get; init; }
+    public Uri? Uri { get; init; }
+    public INavigationParameters Parameters { get; init; }
+    public INavigationResult Result { get; init; }
+}

src/Prism.Maui/Navigation/NavigationRequestType.cs

@@ -0,0 +1,8 @@
+namespace Prism.Navigation;
+
+public enum NavigationRequestType
+{
+    Navigate,
+    GoBack,
+    GoToRoot,
+}