Add popup related navigation extension methods (#2955)

New navigationfrom method added

Author: jamesbrooksbank

samples/CommunityToolkit.Maui.Sample/Pages/Views/Popup/PopupsPage.xaml.cs

@@ -29,6 +29,15 @@ protected override async void OnNavigatedTo(NavigatedToEventArgs args)
 		}
 	}
 
+	protected override async void OnNavigatedFrom(NavigatedFromEventArgs args)
+	{
+		base.OnNavigatedFrom(args);
+		if (args.IsDestinationPageACommunityToolkitPopupPage())
+		{
+			await Toast.Make("Opening Popup").Show();
+		}
+	}
+
 	async void HandleSimplePopupButtonClicked(object? sender, EventArgs e)
 	{
 		var queryAttributes = new Dictionary<string, object>

src/CommunityToolkit.Maui.UnitTests/Extensions/NavigatedFromEventArgsExtensionsTests.cs

@@ -0,0 +1,82 @@
+using CommunityToolkit.Maui.Extensions;
+using CommunityToolkit.Maui.UnitTests.Mocks;
+using CommunityToolkit.Maui.UnitTests.Services;
+using Xunit;
+
+namespace CommunityToolkit.Maui.UnitTests.Extensions;
+
+public class NavigatedFromEventArgsExtensionsTests : BaseViewTest
+{
+	[Fact]
+	public async Task NavigatedFromEventArgsExtensions_IsDestinationPageACommunityToolkitPopupPage_ShouldReturnTrue()
+	{
+		// Arrange
+		TaskCompletionSource<bool?> isDestinationPageACommunityToolkitPopupPageTCS = new();
+		var application = (MockApplication)ServiceProvider.GetRequiredService<IApplication>();
+		var popupService = ServiceProvider.GetRequiredService<IPopupService>();
+
+		var shell = (Shell)(application.Windows[0].Page ?? throw new InvalidOperationException("Unable to retrieve Shell"));
+		var mainPage = shell.CurrentPage;
+		var shellContentPage = new ShellContentPage();
+		shellContentPage.NavigatedFromEventArgsReceived += HandleNavigatedFromEventArgsReceived;
+
+		var shellParameters = new Dictionary<string, object>
+		{
+			{ nameof(ContentPage.BackgroundColor), Colors.Orange }
+		};
+
+
+		// Act
+		await mainPage.Navigation.PushAsync(shellContentPage);
+		await popupService.ShowPopupAsync<ShortLivedMockPageViewModel>(shell, null, shellParameters, TestContext.Current.CancellationToken);
+		var isDestinationPageACommunityToolkitPopupPage = await isDestinationPageACommunityToolkitPopupPageTCS.Task;
+
+		// Assert
+		Assert.True(isDestinationPageACommunityToolkitPopupPage);
+
+		void HandleNavigatedFromEventArgsReceived(object? sender, NavigatedFromEventArgs e)
+		{
+			isDestinationPageACommunityToolkitPopupPageTCS.SetResult(e.IsDestinationPageACommunityToolkitPopupPage());
+		}
+	}
+
+	[Fact]
+	public async Task NavigatedFromEventArgsExtensions_IsDestinationPageACommunityToolkitPopupPage_ShouldReturnFalse()
+	{
+		// Arrange
+		TaskCompletionSource<bool?> isDestinationPageACommunityToolkitPopupPageTCS = new();
+		var application = (MockApplication)ServiceProvider.GetRequiredService<IApplication>();
+
+		var shell = (Shell)(application.Windows[0].Page ?? throw new InvalidOperationException("Unable to retrieve Shell"));
+		var mainPage = shell.CurrentPage;
+		var shellContentPage = new ShellContentPage();
+		shellContentPage.NavigatedFromEventArgsReceived += HandleNavigatedFromEventArgsReceived;
+		var newShellContentPage = new ShellContentPage();
+
+
+		// Act
+		await mainPage.Navigation.PushAsync(shellContentPage);
+		//push a new content page on top to make sure the navigation handler doesn't think we're navigating to a popup page
+		await mainPage.Navigation.PushAsync(newShellContentPage);
+		var isDestinationPageACommunityToolkitPopupPage = await isDestinationPageACommunityToolkitPopupPageTCS.Task;
+
+		// Assert
+		Assert.False(isDestinationPageACommunityToolkitPopupPage);
+
+		void HandleNavigatedFromEventArgsReceived(object? sender, NavigatedFromEventArgs e)
+		{
+			isDestinationPageACommunityToolkitPopupPageTCS.SetResult(e.IsDestinationPageACommunityToolkitPopupPage());
+		}
+	}
+
+	sealed class ShellContentPage : ContentPage
+	{
+		public event EventHandler<NavigatedFromEventArgs>? NavigatedFromEventArgsReceived;
+
+		protected override void OnNavigatedFrom(NavigatedFromEventArgs args)
+		{
+			base.OnNavigatedFrom(args);
+			NavigatedFromEventArgsReceived?.Invoke(this, args);
+		}
+	}
+}

src/CommunityToolkit.Maui/Extensions/NavigatedFromEventArgsExtensions.shared.cs

@@ -0,0 +1,16 @@
+using CommunityToolkit.Maui.Views;
+
+namespace CommunityToolkit.Maui.Extensions;
+
+/// <summary>
+/// Extension methods for <see cref="NavigatedFromEventArgs"/>.
+/// </summary>
+public static class NavigatedFromEventArgsExtensions
+{
+	/// <summary>
+	/// Determines whether the previous page was a Community Toolkit <see cref="Popup"/>.
+	/// </summary>
+	/// <param name="args">The current <see cref="NavigatedFromEventArgs"/>.</param>
+	/// <returns>A boolean indicating whether the previous page was a Community Toolkit <see cref="Popup"/>.</returns>
+	public static bool IsDestinationPageACommunityToolkitPopupPage(this NavigatedFromEventArgs args) => args.DestinationPage is PopupPage;
+}