Merge pull request #3039 from PrismLibrary/dev/ds/navigation-tabs

Use RootPage Title/IconImageSource when parent is TabbedPage

e2e/Maui/MauiModule/Views/ViewA.xaml

@@ -4,6 +4,7 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              x:Class="MauiModule.Views.ViewA"
              Title="{Binding Title}"
+             IconImageSource="home.png"
              BackgroundColor="White">
   <Grid RowDefinitions="*,Auto"
         ColumnDefinitions="*,*">
@@ -31,18 +32,18 @@
       </CollectionView.ItemTemplate>
     </CollectionView>
 
-    <Button Text="ViewB" 
+    <Button Text="ViewB"
             Command="{prism:NavigateTo 'ViewB'}"
             Margin="10"
             Grid.Row="1">
       <Button.CommandParameter>
         <prism:Parameter Key="Message" Value="Hi from View A!"/>
       </Button.CommandParameter>
     </Button>
-    <Button Text="Show Alert Dialog" 
+    <Button Text="Show Alert Dialog"
             Command="{Binding ShowPageDialog}"
             Margin="10"
             Grid.Row="1"
             Grid.Column="1"/>
   </Grid>
-</ContentPage>
+</ContentPage>

e2e/Maui/MauiModule/Views/ViewB.xaml

@@ -3,6 +3,7 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              x:Class="MauiModule.Views.ViewB"
              Title="{Binding Title}"
+             IconImageSource="profile.png"
              BackgroundColor="White">
   <Grid RowDefinitions="*,Auto"
         ColumnDefinitions="*,*">
@@ -41,4 +42,4 @@
             Grid.Row="1"
             Grid.Column="1"/>
   </Grid>
-</ContentPage>
+</ContentPage>

e2e/Maui/MauiModule/Views/ViewC.xaml

@@ -3,6 +3,7 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
              x:Class="MauiModule.Views.ViewC"
              Title="{Binding Title}"
+             IconImageSource="setting.png"
              BackgroundColor="White">
   <Grid RowDefinitions="*,Auto"
         ColumnDefinitions="*,*">
@@ -41,4 +42,4 @@
             Grid.Row="1"
             Grid.Column="1"/>
   </Grid>
-</ContentPage>
+</ContentPage>

src/Maui/Prism.Maui/Behaviors/NavigationPageTabbedParentBehavior.cs

@@ -0,0 +1,56 @@
+namespace Prism.Behaviors;
+
+/// <summary>
+/// Adds a behavior to use the RootPage Title and IconImageSource if they are not set on the NavigaitonPage
+/// when the NavigationPage has a TabbedPage parent.
+/// </summary>
+public sealed class NavigationPageTabbedParentBehavior : BehaviorBase<NavigationPage>
+{
+    private static readonly BindableProperty NavigationPageRootPageMonitorTitleProperty =
+        BindableProperty.CreateAttached("NavigationPageRootPageMonitorTitle", typeof(bool), typeof(NavigationPageTabbedParentBehavior), false);
+
+    private static readonly BindableProperty NavigationPageRootPageMonitorIconImageSourceProperty =
+        BindableProperty.CreateAttached("NavigationPageRootPageMonitorIconImageSource", typeof(bool), typeof(NavigationPageTabbedParentBehavior), false);
+
+    private static bool GetNavigationPageRootPageMonitorTitle(BindableObject bindable) =>
+        (bool)bindable.GetValue(NavigationPageRootPageMonitorTitleProperty);
+
+    private static void SetNavigationPageRootPageMonitorTitle(BindableObject bindable, bool monitorTitle) =>
+        bindable.SetValue(NavigationPageRootPageMonitorTitleProperty, monitorTitle);
+
+    private static bool GetNavigationPageRootPageMonitorIconImageSource(BindableObject bindable) =>
+        (bool)bindable.GetValue(NavigationPageRootPageMonitorIconImageSourceProperty);
+
+    private static void SetNavigationPageRootPageMonitorIconImageSource(BindableObject bindable, bool monitorTitle) =>
+        bindable.SetValue(NavigationPageRootPageMonitorIconImageSourceProperty, monitorTitle);
+
+    /// <inheritdoc />
+    protected override void OnAttachedTo(NavigationPage bindable)
+    {
+        base.OnAttachedTo(bindable);
+        SetNavigationPageRootPageMonitorTitle(bindable, !bindable.IsSet(NavigationPage.TitleProperty));
+        SetNavigationPageRootPageMonitorIconImageSource(bindable, !bindable.IsSet(NavigationPage.IconImageSourceProperty));
+        bindable.ParentChanged += OnParentChanged;
+        if (bindable.Parent is TabbedPage)
+            OnParentChanged(bindable, EventArgs.Empty);
+    }
+
+    /// <inheritdoc />
+    protected override void OnDetachingFrom(NavigationPage bindable)
+    {
+        base.OnDetachingFrom(bindable);
+        bindable.ParentChanged -= OnParentChanged;
+    }
+
+    private void OnParentChanged(object sender, EventArgs e)
+    {
+        if (sender is not NavigationPage navigationPage || navigationPage.Parent is not TabbedPage)
+            return;
+
+        if (GetNavigationPageRootPageMonitorTitle(navigationPage))
+            navigationPage.SetBinding(NavigationPage.TitleProperty, new Binding("RootPage.Title", BindingMode.OneWay, source: navigationPage));
+
+        if (GetNavigationPageRootPageMonitorIconImageSource(navigationPage))
+            navigationPage.SetBinding(NavigationPage.IconImageSourceProperty, new Binding("RootPage.IconImageSource", BindingMode.OneWay, source: navigationPage));
+    }
+}

src/Maui/Prism.Maui/Navigation/NavigationRegistry.cs

@@ -1,6 +1,5 @@
 using Prism.Behaviors;
 using Prism.Common;
-using Prism.Ioc;
 using Prism.Mvvm;
 using Prism.Navigation.Xaml;
 using TabbedPage = Microsoft.Maui.Controls.TabbedPage;
@@ -33,6 +32,18 @@ private static void ConfigurePage(IContainerProvider container, Page page)
         {
             var scope = container.CreateScope();
             ConfigurePage(scope, navPage.RootPage);
+
+            if (navPage.RootPage.GetType().Equals(typeof(Page)))
+            {
+                if (navPage.RootPage == navPage.CurrentPage)
+                {
+                    navPage.Pushed += PreventDefaultRootPage;
+                }
+                else
+                {
+                    navPage.Navigation.RemovePage(navPage.RootPage);
+                }
+            }
         }
 
         if (page.GetContainerProvider() is null)
@@ -47,11 +58,34 @@ private static void ConfigurePage(IContainerProvider container, Page page)
 #endif
             throw new NavigationException($"Invalid Scope provided. The current scope Page Accessor contains '{accessor.Page.GetType().FullName}', expected '{page.GetType().FullName}'.", page);
         }
-        else if (accessor.Page is null)
-            accessor.Page = page;
+
+        accessor.Page ??= page;
 
         var behaviorFactories = container.Resolve<IEnumerable<IPageBehaviorFactory>>();
         foreach (var factory in behaviorFactories)
             factory.ApplyPageBehaviors(page);
     }
+
+    private static void PreventDefaultRootPage(object sender, NavigationEventArgs e)
+    {
+        if (sender is not NavigationPage navigationPage)
+        {
+            return;
+        }
+
+        if (!navigationPage.RootPage.GetType().Equals(typeof(Page)))
+        {
+            navigationPage.Pushed -= PreventDefaultRootPage;
+            return;
+        }
+
+        if (navigationPage.RootPage == navigationPage.CurrentPage)
+        {
+            return;
+        }
+
+        navigationPage.Pushed -= PreventDefaultRootPage;
+
+        navigationPage.Navigation.RemovePage(navigationPage.RootPage);
+    }
 }

src/Maui/Prism.Maui/PrismAppBuilder.cs

@@ -261,6 +261,7 @@ private void RegisterDefaultRequiredTypes(IContainerRegistry containerRegistry)
         containerRegistry.RegisterManySingleton<PrismWindowManager>();
         containerRegistry.RegisterPageBehavior<NavigationPage, NavigationPageSystemGoBackBehavior>();
         containerRegistry.RegisterPageBehavior<NavigationPage, NavigationPageActiveAwareBehavior>();
+        containerRegistry.RegisterPageBehavior<NavigationPage, NavigationPageTabbedParentBehavior>();
         containerRegistry.RegisterPageBehavior<TabbedPage, TabbedPageActiveAwareBehavior>();
         containerRegistry.RegisterPageBehavior<PageLifeCycleAwareBehavior>();
         containerRegistry.RegisterPageBehavior<PageScopeBehavior>();

tests/Maui/Prism.DryIoc.Maui.Tests/Fixtures/Navigation/NavigationTests.cs

@@ -276,6 +276,49 @@ public async Task TabbedPageSelectTabSetsCurrentTabWithNavigationPageTab()
         Assert.IsType<MockViewB>(navPage.CurrentPage);
     }
 
+    [Fact]
+    public async Task NavigationPage_DoesNotHave_MauiPage_AsRootPage()
+    {
+        var mauiApp = CreateBuilder(prism => prism
+            .OnAppStart("NavigationPage/MockViewA"))
+            .Build();
+        var window = GetWindow(mauiApp);
+
+        Assert.IsAssignableFrom<NavigationPage>(window.Page);
+        var navPage = window.Page as NavigationPage;
+
+        Assert.NotNull(navPage);
+        Assert.IsNotType<Page>(navPage.RootPage);
+        Assert.IsType<MockViewA>(navPage.RootPage);
+
+        Assert.Same(navPage.RootPage, navPage.CurrentPage);
+    }
+
+    [Fact]
+    public async Task NavigationPage_UsesRootPageTitle_WithTabbedParent()
+    {
+        var mauiApp = CreateBuilder(prism => prism
+            .OnAppStart(n => n.CreateBuilder()
+                .AddTabbedSegment(s => s
+                    .CreateTab(t => t.AddNavigationPage()
+                                                .AddSegment("MockViewA")))
+                .NavigateAsync()))
+            .Build();
+        var window = GetWindow(mauiApp);
+        Assert.IsAssignableFrom<TabbedPage>(window.Page);
+        var tabbed = window.Page as TabbedPage;
+
+        Assert.NotNull(tabbed);
+
+        Assert.Single(tabbed.Children);
+        var child = tabbed.Children[0];
+        Assert.IsAssignableFrom<NavigationPage>(child);
+        var navPage = child as NavigationPage;
+
+        Assert.Equal(navPage.Title, navPage.RootPage.Title);
+        Assert.Equal(MockViewA.ExpectedTitle, navPage.Title);
+    }
+
     private void TestPage(Page page)
     {
         Assert.NotNull(page.BindingContext);

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/Views/MockViewA.cs

@@ -1,3 +1,12 @@
 namespace Prism.DryIoc.Maui.Tests.Mocks.Views;
 
-public class MockViewA : ContentPage { }
+public class MockViewA : ContentPage
+{
+    public const string ExpectedTitle = "Mock View A";
+    public static readonly ImageSource ExpectedIconImageSource = "home.png";
+    public MockViewA()
+    {
+        Title = ExpectedTitle;
+        IconImageSource = ExpectedIconImageSource;
+    }
+}