Fix initial page and back button Navigation events

src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using CoreGraphics;
+using Foundation;
 using Microsoft.Maui.Controls.Internals;
 using Microsoft.Maui.Controls.Platform;
 using Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific;
@@ -42,8 +43,9 @@ public class NavigationRenderer : UINavigationController, IPlatformViewHandler
 		ViewHandlerDelegator<NavigationPage> _viewHandlerWrapper;
 		bool _navigating = false;
 		VisualElement _element;
+		bool _uiRequestedPop; // User tapped the back button or swiped to navigate back
 
-		[Preserve(Conditional = true)]
+		[Internals.Preserve(Conditional = true)]
 		public NavigationRenderer() : base(typeof(MauiControlsNavigationBar), null)
 		{
 			_viewHandlerWrapper = new ViewHandlerDelegator<NavigationPage>(Mapper, CommandMapper, this);
@@ -780,7 +782,7 @@ void UpdateToolBarVisible()
 			TopViewController?.NavigationItem?.TitleView?.LayoutSubviews();
 		}
 
-		internal async Task UpdateFormsInnerNavigation(Page pageBeingRemoved)
+		async Task UpdateFormsInnerNavigation(Page pageBeingRemoved)
 		{
 			if (NavPage == null)
 				return;
@@ -789,9 +791,24 @@ internal async Task UpdateFormsInnerNavigation(Page pageBeingRemoved)
 
 			_ignorePopCall = true;
 			if (Element.Navigation.NavigationStack.Contains(pageBeingRemoved))
+			{
 				await (NavPage as INavigationPageController)?.RemoveAsyncInner(pageBeingRemoved, false, true);
+				if (_uiRequestedPop)
+				{
+					NavPage?.SendNavigatedFromHandler(pageBeingRemoved);
+				}
+			}
+
 			_ignorePopCall = false;
+			_uiRequestedPop = false;
+		}
 
+		[Export("navigationBar:shouldPopItem:")]
+		[Internals.Preserve(Conditional = true)]
+		internal bool ShouldPopItem(UINavigationBar _, UINavigationItem __)
+		{
+			_uiRequestedPop = true;
+			return true;
 		}
 
 		internal static void SetFlyoutLeftBarButton(UIViewController containerController, FlyoutPage FlyoutPage)
@@ -959,7 +976,9 @@ void SetupLines()
 
 		class MauiNavigationDelegate : UINavigationControllerDelegate
 		{
+			bool _finishedWithInitialNavigation;
 			readonly WeakReference<NavigationRenderer> _navigation;
+
 			public MauiNavigationDelegate(NavigationRenderer navigationRenderer)
 			{
 				_navigation = new WeakReference<NavigationRenderer>(navigationRenderer);
@@ -974,6 +993,12 @@ public override void DidShowViewController(UINavigationController navigationCont
 					{
 						pvc.UpdateFrames();
 					}
+
+					if (r.Element is NavigationPage np && !_finishedWithInitialNavigation)
+					{
+						_finishedWithInitialNavigation = true;
+						np.SendNavigatedFromHandler(null);
+					}
 				}
 			}
 

src/Controls/src/Core/HandlerImpl/NavigationPage/NavigationPage.Legacy.cs

@@ -14,10 +14,9 @@ namespace Microsoft.Maui.Controls
 	/// <include file="../../../../docs/Microsoft.Maui.Controls/NavigationPage.xml" path="Type[@FullName='Microsoft.Maui.Controls.NavigationPage']/Docs/*" />
 	public partial class NavigationPage : INavigationPageController
 	{
-		internal async Task<Page> PopAsyncInner(
+		async Task<Page> PopAsyncInner(
 			bool animated,
-			bool fast,
-			bool requestedFromHandler)
+			bool fast)
 		{
 			if (NavigationPageController.StackDepth == 1)
 			{
@@ -27,16 +26,15 @@ internal async Task<Page> PopAsyncInner(
 			var page = (Page)InternalChildren.Last();
 			var previousPage = CurrentPage;
 			SendNavigating();
-			var removedPage = await RemoveAsyncInner(page, animated, fast, requestedFromHandler);
+			var removedPage = await RemoveAsyncInner(page, animated, fast);
 			SendNavigated(previousPage);
 			return removedPage;
 		}
 
-		internal async Task<Page> RemoveAsyncInner(
+		async Task<Page> RemoveAsyncInner(
 			Page page,
 			bool animated,
-			bool fast,
-			bool requestedFromHandler)
+			bool fast)
 		{
 			if (NavigationPageController.StackDepth == 1)
 			{
@@ -53,7 +51,7 @@ internal async Task<Page> RemoveAsyncInner(
 			var removed = true;
 
 			EventHandler<NavigationRequestedEventArgs> requestPop = _popRequested;
-			if (requestPop != null && !requestedFromHandler)
+			if (requestPop != null)
 			{
 				requestPop(this, args);
 
@@ -74,15 +72,14 @@ internal async Task<Page> RemoveAsyncInner(
 			return page;
 		}
 
-
 		Task<Page> INavigationPageController.PopAsyncInner(bool animated, bool fast)
 		{
-			return PopAsyncInner(animated, fast, false);
+			return PopAsyncInner(animated, fast);
 		}
 
 		Task<Page> INavigationPageController.RemoveAsyncInner(Page page, bool animated, bool fast)
 		{
-			return RemoveAsyncInner(page, animated, fast, false);
+			return RemoveAsyncInner(page, animated, fast);
 		}
 
 		EventHandler<NavigationRequestedEventArgs> _popRequested;
@@ -207,6 +204,20 @@ async Task PushAsyncInner(Page page, bool animated)
 			Pushed?.Invoke(this, args);
 		}
 
+#if IOS
+		// Because iOS currently doesn't use our `IStackNavigationView` structures
+		// there are scenarios where the legacy handler needs to alert the xplat
+		// code of when a navigation has occurred.
+		// For example, initial load and when the user taps the back button
+		internal void SendNavigatedFromHandler(Page previousPage)
+		{
+			if (CurrentPage.HasNavigatedTo)
+				return;
+
+			SendNavigated(previousPage);
+		}
+#endif
+
 		void PushPage(Page page)
 		{
 			InternalChildren.Add(page);

src/Controls/src/Core/NavigationPage.cs

@@ -377,13 +377,6 @@ protected override bool OnBackButtonPressed()
 			return base.OnBackButtonPressed();
 		}
 
-		internal void InitialNativeNavigationStackLoaded()
-		{
-			SendNavigated(null);
-		}
-
-
-
 		void SendNavigated(Page previousPage)
 		{
 			previousPage?.SendNavigatedFrom(new NavigatedFromEventArgs(CurrentPage));

src/Controls/tests/Core.UnitTests/PageLifeCycleTests.cs

@@ -6,14 +6,18 @@ namespace Microsoft.Maui.Controls.Core.UnitTests
 
 	public class PageLifeCycleTests : BaseTestFixture
 	{
-		[Theory]
-		[InlineData(false)]
-		[InlineData(true)]
-		public void NavigationPageInitialPage(bool useMaui)
+		[Fact]
+		// This test isn't valid for non handler based
+		// navigation because the initial navigated event
+		// fires from the legacy code instead of the
+		// new handler code
+		// We have device tests to also verify this works on 
+		// each platform
+		public async Task NavigationPageInitialPage()
 		{
 			var lcPage = new LCPage();
-			NavigationPage navigationPage = new TestNavigationPage(useMaui, lcPage);
-			navigationPage.InitialNativeNavigationStackLoaded();
+			var navigationPage = new TestNavigationPage(true, lcPage);
+			await navigationPage.NavigatingTask;
 			Assert.Null(lcPage.NavigatingFromArgs);
 			Assert.Null(lcPage.NavigatedFromArgs);
 			Assert.NotNull(lcPage.NavigatedToArgs);

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

@@ -39,7 +39,7 @@ public async Task<bool> SendBackButtonPressedAsync()
 			return result;
 		}
 
-
+		public Task NavigatingTask => Handler?.NavigatingTask ?? Task.CompletedTask;
 	}
 
 	public class TestNavigationHandler : ViewHandler<NavigationPage, object>
@@ -54,24 +54,36 @@ public static PropertyMapper<IStackNavigationView, TestNavigationHandler> Naviga
 
 		public NavigationRequest CurrentNavigationRequest { get; private set; }
 
+		TaskCompletionSource _navigationSource;
+
+		public Task NavigatingTask => (_navigationSource?.Task ?? Task.CompletedTask);
 
-		public void CompleteCurrentNavigation()
+		public async void CompleteCurrentNavigation()
 		{
 			if (CurrentNavigationRequest == null)
 				throw new InvalidOperationException("No Active Navigation in the works");
 
 			var newStack = CurrentNavigationRequest.NavigationStack.ToList();
 			CurrentNavigationRequest = null;
 
+			var source = _navigationSource;
+			_navigationSource = null;
+
 			if ((this as IElementHandler).VirtualView is IStackNavigation sn)
 				sn.NavigationFinished(newStack);
+
+
+			await Task.Delay(1);
+			source.SetResult();
 		}
 
 		async void RequestNavigation(NavigationRequest navigationRequest)
 		{
-			if (CurrentNavigationRequest != null)
+			if (CurrentNavigationRequest != null || _navigationSource != null)
 				throw new InvalidOperationException("Already Processing Navigation");
 
+
+			_navigationSource = new TaskCompletionSource();
 			CurrentNavigationRequest = navigationRequest;
 
 			await Task.Delay(10);

src/Controls/tests/DeviceTests/Elements/NavigationPage/NavigationPageTests.cs

@@ -50,6 +50,43 @@ await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(navPage), async
 			});
 		}
 
+		[Fact]
+		public async Task InitialPageFiresNavigatedEvent()
+		{
+			SetupBuilder();
+			var page = new ContentPage();
+			var navPage = new NavigationPage(page) { Title = "App Page" };
+
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(navPage), async (handler) =>
+			{
+				await OnNavigatedToAsync(page);
+				Assert.True(page.HasNavigatedTo);
+			});
+		}
+
+		[Fact]
+		public async Task PushedPageFiresNavigatedEventOnInitialLoad()
+		{
+			SetupBuilder();
+
+			bool pageFiredNavigated = false;
+			var page = new ContentPage();
+			page.NavigatedTo += (_, _) => pageFiredNavigated = true;
+
+			var page2 = new ContentPage();
+
+			var navPage = new NavigationPage(page) { Title = "App Page" };
+			await navPage.PushAsync(page2);
+
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(navPage), async (handler) =>
+			{
+				await OnNavigatedToAsync(page2);
+				Assert.True(page2.HasNavigatedTo);
+			});
+
+			Assert.False(pageFiredNavigated);
+		}
+
 #if !IOS && !MACCATALYST
 		[Fact(DisplayName = "Back Button Visibility Changes with push/pop")]
 		public async Task BackButtonVisibilityChangesWithPushPop()

src/Controls/tests/DeviceTests/Elements/NavigationPage/NavigationPageTests.iOS.cs

@@ -1,8 +1,41 @@
-using Xunit;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Platform;
+using Microsoft.Maui.Controls.Platform;
+using Microsoft.Maui.Controls.Handlers.Compatibility;
+using Microsoft.Maui.DeviceTests.Stubs;
+using Microsoft.Maui.Handlers;
+using Microsoft.Maui.Hosting;
+using UIKit;
+using Xunit;
 
 namespace Microsoft.Maui.DeviceTests
 {
 	public partial class NavigationPageTests : ControlsHandlerTestBase
 	{
+		[Fact]
+		public async Task NavigatingBackViaBackButtonFiresNavigatedEvent()
+		{
+			SetupBuilder();
+			var page = new ContentPage();
+
+			var navPage = new NavigationPage(page) { Title = "App Page" };
+
+			await navPage.PushAsync(new ContentPage());
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(navPage), async (handler) =>
+			{
+				await OnNavigatedToAsync(navPage.CurrentPage);
+				var navController = navPage.Handler as UINavigationController;
+
+				Assert.False(page.HasNavigatedTo);
+				navController.NavigationBar.TapBackButton();
+				await OnNavigatedToAsync(page);
+				Assert.True(page.HasNavigatedTo);
+			});
+		}
 	}
 }