App Crash during Scroll Animation while navigating away from Page - f…

…ix (#22492)

* Fix #22443 & UITest

* Update ScrollViewHandler.Android.cs & move tests

* Fixed the UI test

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue22443.cs

@@ -0,0 +1,24 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue22443 : _IssuesUITest
+{
+    public Issue22443(TestDevice device)
+		: base(device)
+	{ }
+
+    public override string Issue => "App Crash on Scroll Animation while navigating away from Page";
+
+    [Test]
+	public void NoExceptionShouldBeThrown()
+	{
+		App.WaitForElement("button");
+		App.Click("button");
+		App.WaitForElement("button");
+
+		//The test passes if no exception is thrown
+	}
+}

src/Controls/tests/TestCases/Issues/Issue22443.xaml

@@ -0,0 +1,7 @@
+<?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.Issue22443"
+             Title="Issue22443">
+    <Button Text="Navigate to next page" AutomationId="button" Clicked="Button_Clicked"/>
+</ContentPage>

src/Controls/tests/TestCases/Issues/Issue22443.xaml.cs

@@ -0,0 +1,81 @@
+using Microsoft.Maui.ApplicationModel;
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.Xaml;
+using Microsoft.Maui.Graphics;
+using System;
+using System.Threading.Tasks;
+
+namespace Maui.Controls.Sample.Issues;
+
+[XamlCompilation(XamlCompilationOptions.Compile)]
+[Issue(IssueTracker.Github, 22443, "App Crash on Scroll Animation while navigating away from Page", PlatformAffected.Android)]
+public partial class Issue22443NavPage : NavigationPage
+{
+	public Issue22443NavPage() : base(new Issue22443())
+	{
+
+	}
+}
+
+public partial class Issue22443 : ContentPage
+{
+	public Issue22443()
+	{
+		InitializeComponent();
+	}
+
+	void Button_Clicked(object sender, EventArgs e)
+	{
+		Navigation.PushAsync(new Issue22443ScrollPage());
+	}
+}
+
+public class Issue22443ScrollPage : ContentPage
+{
+	private ScrollView _scrollView;
+
+	public Issue22443ScrollPage()
+	{
+		_scrollView = new ScrollView
+		{
+			Content = new VerticalStackLayout
+			{
+				Children =
+				{
+					new BoxView
+					{
+						HeightRequest = 10000,
+						Background = new LinearGradientBrush(
+							new GradientStopCollection
+							{
+								new GradientStop(Colors.White, .1f),
+								new GradientStop(Colors.Black, .9f)
+							})
+					},
+					new Label
+					{
+						FontSize = 40,
+						Text = "End of Second Page",
+						HorizontalOptions = LayoutOptions.Center,
+					},
+				}
+			}
+		};
+
+		Content = _scrollView;
+	}
+
+	protected override async void OnAppearing()
+	{
+		MainThread.BeginInvokeOnMainThread(() =>_scrollView!.ScrollToAsync(0, 10000, true));
+
+		await Task.Delay(200);
+		await Navigation.PopAsync();
+	}
+
+	protected override void OnDisappearing()
+	{
+		base.OnDisappearing();
+		_scrollView?.Handler?.DisconnectHandler();
+	}
+}

src/Core/src/Handlers/ScrollView/ScrollViewHandler.Android.cs

@@ -147,7 +147,13 @@ public static void MapRequestScrollTo(IScrollViewHandler handler, IScrollView sc
 			var verticalOffsetDevice = (int)context.ToPixels(request.VerticalOffset);
 
 			handler.PlatformView.ScrollTo(horizontalOffsetDevice, verticalOffsetDevice,
-				request.Instant, () => handler.VirtualView.ScrollFinished());
+				request.Instant, () =>
+				{
+					if (handler.IsConnected())
+					{
+						handler.VirtualView.ScrollFinished();
+					}
+				});
 		}
 
 		/*