[Android] Fixed incorrect tab content display in TabbedPage

src/Controls/src/Core/Platform/Android/TabbedPageManager.cs

@@ -473,7 +473,7 @@ void UpdateIgnoreContainerAreas()
 				child.IgnoresContainerArea = child is NavigationPage;
 		}
 
-		void UpdateOffscreenPageLimit()
+		internal void UpdateOffscreenPageLimit()
 		{
 			_viewPager.OffscreenPageLimit = Element.OnThisPlatform().OffscreenPageLimit();
 		}

src/Controls/src/Core/TabbedPage/TabbedPage.Android.cs

@@ -98,5 +98,10 @@ public static void MapIsSwipePagingEnabled(ITabbedViewHandler handler, TabbedPag
 		{
 			view._tabbedPageManager?.UpdateSwipePaging();
 		}
+
+		internal static void MapOffscreenPageLimit(ITabbedViewHandler handler, TabbedPage view)
+		{
+			view._tabbedPageManager?.UpdateOffscreenPageLimit();
+		}
 	}
 }

src/Controls/src/Core/TabbedPage/TabbedPage.Mapper.cs

@@ -21,6 +21,7 @@ public partial class TabbedPage
 			TabbedViewHandler.Mapper.ReplaceMapping<TabbedPage, ITabbedViewHandler>(nameof(CurrentPage), MapCurrentPage);
 #if ANDROID
 			TabbedViewHandler.Mapper.ReplaceMapping<TabbedPage, ITabbedViewHandler>(PlatformConfiguration.AndroidSpecific.TabbedPage.IsSwipePagingEnabledProperty.PropertyName, MapIsSwipePagingEnabled);
+			TabbedViewHandler.Mapper.ReplaceMapping<TabbedPage, ITabbedViewHandler>(PlatformConfiguration.AndroidSpecific.TabbedPage.OffscreenPageLimitProperty.PropertyName, MapOffscreenPageLimit);
 #endif
 
 #if WINDOWS || ANDROID || TIZEN

src/Controls/tests/DeviceTests/Elements/TabbedPage/TabbedPageTests.cs

@@ -183,7 +183,6 @@ await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(tabbedPage), asy
 					var nextPage = tabbedPage.Children[pageIndex];
 					tabbedPage.CurrentPage = nextPage;
 					await OnNavigatedToAsync(nextPage);
-					previousPage.Handler.DisconnectHandler();
 				}
 			});
 		}

src/Controls/tests/TestCases.HostApp/Issues/23732Page.xaml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues._23732Page"
+             xmlns:local="clr-namespace:Maui.Controls.Sample.Issues">
+
+  <Grid RowDefinitions="Auto,*">
+    <CollectionView
+            Grid.Row="1"
+            Margin="0,20"
+            ItemsSource="{Binding Models}">
+            <CollectionView.ItemTemplate>
+                <DataTemplate>
+                    <Grid
+                        BackgroundColor="Gray"
+                        HeightRequest="60"
+                        ColumnDefinitions="*,Auto">
+                        <BoxView Grid.ColumnSpan="2" Color="White"/>
+                        <Label
+                            Margin="20,0"
+                            Text="Item"
+                            VerticalOptions="Center"
+                            TextColor="Blue"/>
+                        <BoxView Grid.ColumnSpan="2"/>
+                    </Grid>
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </CollectionView>
+    </Grid>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/23732Page.xaml.cs

@@ -0,0 +1,68 @@
+using System.Collections.ObjectModel;
+
+namespace Maui.Controls.Sample.Issues
+{
+	public partial class _23732Page : ContentPage
+	{
+		public ObservableCollection<string> Models { get; } = new();
+		public _23732Page(bool isPage4)
+		{
+			InitializeComponent();
+			BindingContext = this;
+			for (int i = 0; i <= 6; i++)
+			{
+				Models.Add(string.Empty);
+			}
+
+			if (isPage4)
+			{
+				var label = new Label
+				{
+					Text = "page4",
+					AutomationId = "label",
+					HorizontalTextAlignment = TextAlignment.Center
+				};
+				(Content as Grid)?.Children.Insert(0, label);
+			}
+		}
+
+		private string _label;
+		public string Label
+		{
+			get => _label;
+			set
+			{
+				if (_label != value)
+				{
+					_label = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+	}
+
+	[Issue(IssueTracker.Github, 23732, "TabBar content not displayed properly", PlatformAffected.Android)]
+	public partial class Issue23732 : TabbedPage
+	{
+		public Issue23732()
+		{
+			for (int i = 1; i <= 5; i++)
+			{
+				Children.Add(CreateNavigationPage($"Page {i}", $"page{i}"));
+			}
+		}
+
+		private NavigationPage CreateNavigationPage(string title, string label)
+		{
+			var mainPage = new _23732Page(label == "page4")
+			{
+				Label = label
+			};
+
+			return new NavigationPage(mainPage)
+			{
+				Title = title
+			};
+		}
+	}
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue21640.cs

@@ -0,0 +1,65 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 21640, "TabbedPage content was not updated", PlatformAffected.Android)]
+	public partial class Issue21640 : TabbedPage
+	{
+		private Page _savedPage;
+		public Issue21640()
+		{
+			var homePage = new ContentPage
+			{
+				Title = "Home",
+				Content = new Button
+				{
+					Text = "Toggle Tab",
+					Command = new Command(ToggleTab),
+					AutomationId = "ToogleTabButton"
+				}
+			};
+
+			var newPage = CreateNewPage();
+			_savedPage = new NavigationPage(newPage) { Title = "Settings" };
+			Children.Add(new NavigationPage(homePage) { Title = "Home" });
+		}
+
+		private async void ToggleTab()
+		{
+			if (Children.Count == 1)
+			{
+				await MainThread.InvokeOnMainThreadAsync(() =>
+				{
+					Children.Add(_savedPage);
+				});
+			}
+			else if (Children.Count == 2)
+			{
+				_savedPage = Children[1];
+				await MainThread.InvokeOnMainThreadAsync(() =>
+				{
+					Children.RemoveAt(1);
+				});
+			}
+		}
+
+		private Page CreateNewPage()
+		{
+			return new ContentPage
+			{
+				Title = "NewPage",
+				Content = new VerticalStackLayout
+				{
+					Children =
+					{
+						new Label
+						{
+							Text = "Welcome to .NET MAUI!",
+							VerticalOptions = LayoutOptions.Center,
+							HorizontalOptions = LayoutOptions.Center,
+							AutomationId = "label"
+						}
+					}
+				}
+			};
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue21640.cs

@@ -0,0 +1,43 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue21640 : _IssuesUITest
+	{
+		public Issue21640(TestDevice testDevice) : base(testDevice)
+		{
+		}
+		public override string Issue => "TabbedPage content was not updated";
+
+		[Test]
+		[Category(UITestCategories.TabbedPage)]
+		public void TabbedPageContentUpdatesCorrectly()
+		{
+#if ANDROID
+			string tab1Title = "HOME";
+			string tab2Title = "SETTINGS";
+#else
+			string tab1Title = "Home";
+			string tab2Title = "Settings";
+#endif
+			string toggleTabButtonId = "ToogleTabButton";
+			App.WaitForElement(toggleTabButtonId);
+			App.Tap(toggleTabButtonId);
+			App.Tap(tab2Title);
+			App.WaitForElement("label");
+
+			// The issue occurs when repeatedly removing and re-adding the tab while navigating between tabs.
+			for (int i = 0; i < 3; i++)
+			{
+				App.Tap(tab1Title);
+				App.WaitForElement(toggleTabButtonId);
+				App.Tap(toggleTabButtonId); // Removes the tab
+				App.Tap(toggleTabButtonId); // Re-adds the tab
+				App.Tap(tab2Title);
+				App.WaitForElement("label");
+			}
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue23732.cs

@@ -0,0 +1,29 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue23732: _IssuesUITest
+	{
+		public Issue23732(TestDevice testDevice) : base(testDevice)
+		{
+		}
+		public override string Issue => "TabBar content not displayed properly";
+
+		[Test]
+		[Category(UITestCategories.TabbedPage)]
+		public void TabbedPageTabContentUpdated()
+		{
+#if ANDROID
+			string pageTitle = "PAGE 4";
+#else
+			string pageTitle = "Page 4";
+#endif
+			App.WaitForElement(pageTitle);
+			App.Tap(pageTitle);
+			var label = App.WaitForElement("label");
+			Assert.That(label.GetText(), Is.EqualTo("page4"));
+		}
+	}
+}