Multi Window Support

src/Controls/samples/Controls.Sample.SingleProject/Platforms/MacCatalyst/Info.plist

@@ -26,5 +26,26 @@
 	</array>
 	<key>XSAppIconAssets</key>
 	<string>Assets.xcassets/appicon.appiconset</string>
+    <key>UIApplicationSceneManifest</key>
+	<dict>
+		<key>UIApplicationSupportsMultipleScenes</key>
+		<true/>
+		<key>UISceneConfigurations</key>
+		<dict>
+			<key>UIWindowSceneSessionRoleApplication</key>
+			<array>
+				<dict>
+					<key>UISceneConfigurationName</key>
+					<string>__MAUI_DEFAULT_SCENE_CONFIGURATION__</string>
+					<key>UISceneDelegateClassName</key>
+					<string>SceneDelegate</string>
+				</dict>
+			</array>
+		</dict>
+	</dict>
+	<key>NSUserActivityTypes</key>
+	<array>
+		<string>com.microsoft.maui.sample</string>
+	</array>
 </dict>
 </plist>

src/Controls/samples/Controls.Sample.SingleProject/Platforms/MacCatalyst/SceneDelegate.cs

@@ -0,0 +1,13 @@
+using Foundation;
+using UIKit;
+using Microsoft.Maui;
+
+namespace Maui.Controls.Sample
+{
+	[Register("SceneDelegate")]
+	public class SceneDelegate : MauiUISceneDelegate
+	{
+
+
+	}
+}

src/Controls/samples/Controls.Sample.SingleProject/Platforms/iOS/Info.plist

@@ -30,5 +30,26 @@
 	<string>Assets.xcassets/appicon.appiconset</string>
 	<key>NSLocationWhenInUseUsageDescription</key>
 	<string>Access to your location is required for cool things to happen!</string>
+    <key>UIApplicationSceneManifest</key>
+	<dict>
+		<key>UIApplicationSupportsMultipleScenes</key>
+		<true/>
+		<key>UISceneConfigurations</key>
+		<dict>
+			<key>UIWindowSceneSessionRoleApplication</key>
+			<array>
+				<dict>
+					<key>UISceneConfigurationName</key>
+					<string>__MAUI_DEFAULT_SCENE_CONFIGURATION__</string>
+					<key>UISceneDelegateClassName</key>
+					<string>SceneDelegate</string>
+				</dict>
+			</array>
+		</dict>
+	</dict>
+	<key>NSUserActivityTypes</key>
+	<array>
+		<string>com.microsoft.maui.sample.default</string>
+	</array>
 </dict>
 </plist>

src/Controls/samples/Controls.Sample.SingleProject/Platforms/iOS/SceneDelegate.cs

@@ -1,59 +1,13 @@
 using Foundation;
 using UIKit;
+using Microsoft.Maui;
 
 namespace Maui.Controls.Sample
 {
 	[Register("SceneDelegate")]
-	public class SceneDelegate : UIResponder, IUIWindowSceneDelegate
+	public class SceneDelegate : MauiUISceneDelegate
 	{
 
-		[Export("window")]
-		public UIWindow Window { get; set; }
-
-		[Export("scene:willConnectToSession:options:")]
-		public void WillConnect(UIScene scene, UISceneSession session, UISceneConnectionOptions connectionOptions)
-		{
-			// Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
-			// If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
-			// This delegate does not imply the connecting scene or session are new (see UIApplicationDelegate `GetConfiguration` instead).
-		}
-
-		[Export("sceneDidDisconnect:")]
-		public void DidDisconnect(UIScene scene)
-		{
-			// Called as the scene is being released by the system.
-			// This occurs shortly after the scene enters the background, or when its session is discarded.
-			// Release any resources associated with this scene that can be re-created the next time the scene connects.
-			// The scene may re-connect later, as its session was not neccessarily discarded (see UIApplicationDelegate `DidDiscardSceneSessions` instead).
-		}
-
-		[Export("sceneDidBecomeActive:")]
-		public void DidBecomeActive(UIScene scene)
-		{
-			// Called when the scene has moved from an inactive state to an active state.
-			// Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive.
-		}
-
-		[Export("sceneWillResignActive:")]
-		public void WillResignActive(UIScene scene)
-		{
-			// Called when the scene will move from an active state to an inactive state.
-			// This may occur due to temporary interruptions (ex. an incoming phone call).
-		}
-
-		[Export("sceneWillEnterForeground:")]
-		public void WillEnterForeground(UIScene scene)
-		{
-			// Called as the scene transitions from the background to the foreground.
-			// Use this method to undo the changes made on entering the background.
-		}
-
-		[Export("sceneDidEnterBackground:")]
-		public void DidEnterBackground(UIScene scene)
-		{
-			// Called as the scene transitions from the foreground to the background.
-			// Use this method to save data, release shared resources, and store enough scene-specific state information
-			// to restore the scene back to its current state.
-		}
+
 	}
 }

src/Controls/samples/Controls.Sample/Pages/MainPage.xaml

@@ -67,18 +67,19 @@
                 Source="header_background"/>
             <Grid
                 RowSpacing="0"
-                Grid.Row="0">
-                <Grid.RowDefinitions>
-                    <RowDefinition Height="Auto" />
-                    <RowDefinition Height="*" />
-                </Grid.RowDefinitions>
+                Grid.Row="0"
+                RowDefinitions="Auto,*,Auto">
                 <Label
                     Text=".NET MAUI"
                     Style="{StaticResource TitleStyle}"/>
                 <Label
                     Grid.Row="1"
                     Text="An open-source framework for building iOS, Android, macOS and Windows apps"
                     Style="{StaticResource SubTitleStyle}"/>
+                <Button
+                    Grid.Row="2"
+                    Text="One more window"
+                    Clicked="ShowNewWindow" />
             </Grid>
             <!-- SECTIONS -->
             <Grid

src/Controls/samples/Controls.Sample/Pages/MainPage.xaml.cs

@@ -1,16 +1,30 @@
 using System;
 using Maui.Controls.Sample.ViewModels;
 using Microsoft.Maui.Controls;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
 
 namespace Maui.Controls.Sample.Pages
 {
 	public partial class MainPage
 	{
+		IServiceProvider _services;
+		MainViewModel _viewModel;
+
 		public MainPage(IServiceProvider services, MainViewModel viewModel)
 		{
 			InitializeComponent();
 
 			BindingContext = viewModel;
+
+			_services = services;
+			_viewModel = viewModel;
+		}
+
+		void ShowNewWindow(object sender, EventArgs e)
+		{
+			var mvm = _services.GetService<MainViewModel>();
+			Application.Current.OpenWindow(new Window(new CustomNavigationPage(_services, mvm)));
 		}
 	}
 }

src/Controls/src/Core/BackgroundingEventArgs.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace Microsoft.Maui.Controls
+{
+	public class BackgroundingEventArgs : EventArgs
+	{
+		public BackgroundingEventArgs(IPersistedState state)
+		{
+			State = state;
+		}
+
+		public IPersistedState State { get; set; }
+	}
+}

src/Controls/src/Core/HandlerImpl/Application.Impl.cs

@@ -8,7 +8,10 @@ namespace Microsoft.Maui.Controls
 {
 	public partial class Application : IApplication
 	{
+		const string MauiWindowIdKey = "__MAUI_WINDOW_ID__";
+
 		readonly List<Window> _windows = new();
+		readonly Dictionary<string, Window> _requestedWindows = new();
 		ILogger<Application>? _logger;
 
 		ILogger<Application>? Logger =>
@@ -21,6 +24,15 @@ public partial class Application : IApplication
 		IWindow IApplication.CreateWindow(IActivationState activationState)
 		{
 			Window? window = null;
+
+			// try get the window that is pending
+			if (activationState.State?.TryGetValue(MauiWindowIdKey, out var requestedWindowId) ?? false)
+			{
+				if (requestedWindowId != null && _requestedWindows.TryGetValue(requestedWindowId, out var w))
+					window = w;
+			}
+
+			// create a new one if there is no pending windows
 			if (window == null)
 			{
 				window = CreateWindow(activationState);
@@ -39,6 +51,26 @@ IWindow IApplication.CreateWindow(IActivationState activationState)
 			return window;
 		}
 
+		void IApplication.OpenWindow(IWindow window)
+		{
+			if (window is Window cwindow)
+				OpenWindow(cwindow);
+		}
+
+		public virtual void OpenWindow(Window window)
+		{
+			var id = Guid.NewGuid().ToString();
+
+			_requestedWindows[id] = window;
+
+			var state = new PersistedState
+			{
+				[MauiWindowIdKey] = id
+			};
+
+			Handler?.Invoke(nameof(IApplication.OpenWindow), new OpenWindowRequest(State: state));
+		}
+
 		public void ThemeChanged()
 		{
 			Current?.TriggerThemeChanged(new AppThemeChangedEventArgs(Current.RequestedTheme));

src/Controls/src/Core/HandlerImpl/Window/Window.Impl.cs

@@ -66,13 +66,15 @@ public Window(Page page)
 		public event EventHandler? Deactivated;
 		public event EventHandler? Stopped;
 		public event EventHandler? Destroying;
+		public event EventHandler<BackgroundingEventArgs>? Backgrounding;
 
 		protected virtual void OnCreated() { }
 		protected virtual void OnResumed() { }
 		protected virtual void OnActivated() { }
 		protected virtual void OnDeactivated() { }
 		protected virtual void OnStopped() { }
 		protected virtual void OnDestroying() { }
+		protected virtual void OnBackgrounding(IPersistedState state) { }
 
 		protected override void OnPropertyChanged([CallerMemberName] string? propertyName = null)
 		{
@@ -213,6 +215,12 @@ void IWindow.Resumed()
 			Application?.SendResume();
 		}
 
+		void IWindow.Backgrounding(IPersistedState state)
+		{
+			Backgrounding?.Invoke(this, new BackgroundingEventArgs(state));
+			OnBackgrounding(state);
+		}
+
 		// Currently this returns MainPage + ModalStack
 		// Depending on how we want this to show up inside LVT
 		// we might want to change this to only return the currently visible page

src/Controls/tests/Core.UnitTests/TestClasses/ApplicationStub.cs

@@ -19,6 +19,11 @@ public IWindow CreateWindow(IActivationState activationState)
 			throw new System.NotImplementedException();
 		}
 
+		public void OpenWindow(IWindow window)
+		{
+			throw new System.NotImplementedException();
+		}
+
 		public void ThemeChanged() { }
 	}
 }

src/Core/src/Core/IApplication.cs

@@ -19,6 +19,8 @@ public interface IApplication : IElement
 		/// <returns>The created window.</returns>
 		IWindow CreateWindow(IActivationState activationState);
 
+		void OpenWindow(IWindow window);
+
 		/// <summary>
 		/// Notify a theme change.
 		/// </summary>

src/Core/src/Core/IWindow.cs

@@ -22,6 +22,8 @@ public interface IWindow : ITitledElement
 
 		void Destroying();
 
+		void Backgrounding(IPersistedState state);
+
 		bool BackButtonClicked();
 	}
 }

src/Core/src/Handlers/Application/ApplicationHandler.Android.cs

@@ -1,5 +1,6 @@
 using Android.App;
 using Microsoft.Extensions.Logging;
+using Microsoft.Maui.Platform;
 
 namespace Microsoft.Maui.Handlers
 {
@@ -9,5 +10,10 @@ public static void MapTerminate(ApplicationHandler handler, IApplication applica
 		{
 			handler.Logger?.LogWarning("Android does not support programmatically terminating the app.");
 		}
+
+		public static void MapOpenWindow(ApplicationHandler handler, IApplication application, object? args)
+		{
+			handler.NativeView?.RequestNewWindow(application, args as OpenWindowRequest);
+		}
 	}
 }

src/Core/src/Handlers/Application/ApplicationHandler.Standard.cs

@@ -7,5 +7,6 @@ public partial class ApplicationHandler : ElementHandler<IApplication, object>
 		protected override object CreateNativeElement() => throw new NotImplementedException();
 
 		public static void MapTerminate(ApplicationHandler handler, IApplication application, object? args) { }
+		public static void MapOpenWindow(ApplicationHandler handler, IApplication application, object? args) { }
 	}
 }

src/Core/src/Handlers/Application/ApplicationHandler.Windows.cs

@@ -1,3 +1,5 @@
+using Microsoft.Maui.Platform;
+
 namespace Microsoft.Maui.Handlers
 {
 	public partial class ApplicationHandler : ElementHandler<IApplication, UI.Xaml.Application>
@@ -6,5 +8,10 @@ public static void MapTerminate(ApplicationHandler handler, IApplication applica
 		{
 			handler.NativeView.Exit();
 		}
+
+		public static void MapOpenWindow(ApplicationHandler handler, IApplication application, object? args)
+		{
+			handler.NativeView?.CreateNativeWindow(application, args as OpenWindowRequest);
+		}
 	}
 }

src/Core/src/Handlers/Application/ApplicationHandler.cs

@@ -21,7 +21,8 @@ public partial class ApplicationHandler
 
 		public static CommandMapper<IApplication, ApplicationHandler> CommandMapper = new(ElementCommandMapper)
 		{
-			[TerminateCommandKey] = MapTerminate
+			[TerminateCommandKey] = MapTerminate,
+			[nameof(IApplication.OpenWindow)] = MapOpenWindow
 		};
 
 		ILogger<ApplicationHandler>? _logger;

src/Core/src/Handlers/Application/ApplicationHandler.iOS.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Runtime.InteropServices;
-using Foundation;
 using Microsoft.Extensions.Logging;
+using Microsoft.Maui.Platform;
 using UIKit;
 
 namespace Microsoft.Maui.Handlers
@@ -17,6 +17,11 @@ public static void MapTerminate(ApplicationHandler handler, IApplication applica
 #endif
 		}
 
+		public static void MapOpenWindow(ApplicationHandler handler, IApplication application, object? args)
+		{
+			handler.NativeView?.RequestNewWindow(application, args as OpenWindowRequest);
+		}
+
 #if __MACCATALYST__
 		class NSApplication
 		{