maui-linux/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue2259.cs

using System;
using System.Collections.ObjectModel;

using Xamarin.Forms;
using Xamarin.Forms.CustomAttributes;

#if UITEST
using NUnit.Framework;
using Xamarin.UITest;
#endif

namespace Xamarin.Forms.Controls
{
	[Preserve (AllMembers=true)]
	[Issue (IssueTracker.Github, 2259, "ListView.ScrollTo crashes app", PlatformAffected.iOS)]
	public class Issue2259 : TestContentPage
	{
		[Preserve (AllMembers = true)]
		public class Person
		{
			public string Name { private set; get; }

			public DateTime Birthday { private set; get; }

			public Color FavoriteColor { private set; get; }

			public Person (string name, DateTime birthday, Color favoriteColor)
			{
				Name = name;
				Birthday = birthday;
				FavoriteColor = favoriteColor;
			}
		};

		int _count = 1;

		protected override void Init ()
		{
			var people = new ObservableCollection<Person> {
				new Person ("Abigail", new DateTime (1975, 1, 15), Color.Aqua),
				new Person ("Bob", new DateTime (1976, 2, 20), Color.Black),
				new Person ("Cathy", new DateTime (1977, 3, 10), Color.Blue),
				new Person ("David", new DateTime (1978, 4, 25), Color.Fuschia),
			};

			var buttonAdd = new Button {
				Text = "Add",
				HorizontalOptions = LayoutOptions.Start,
				VerticalOptions = LayoutOptions.Center,
			};

			var buttonRemove = new Button {
				Text = "Remove",
				HorizontalOptions = LayoutOptions.Center,
				VerticalOptions = LayoutOptions.Center,
			};

			var buttonScrollToBottom = new Button {
				Text = "Bottom",
				HorizontalOptions = LayoutOptions.Start,
				VerticalOptions = LayoutOptions.Center,
			};

			var buttonStack = new StackLayout {
				Orientation = StackOrientation.Horizontal,
				Children = {
					buttonAdd,
					buttonRemove,
					buttonScrollToBottom,
				}
			};

			var listView = new ListView {
				HorizontalOptions = LayoutOptions.FillAndExpand,
				VerticalOptions = LayoutOptions.FillAndExpand,
				ItemsSource = people,
				ItemTemplate = new DataTemplate (() =>
				{
					var nameLabel = new Label ();
					var birthdayLabel = new Label ();
					var boxView = new BoxView ();

					var stack = new StackLayout {
						Padding = new Thickness (0, 5),
						Orientation = StackOrientation.Horizontal,
						BackgroundColor = Color.Black,
						Children = {
							boxView,
							new StackLayout {
								VerticalOptions = LayoutOptions.Center,
								Spacing = 0,
								Children = {
									nameLabel,
									birthdayLabel
								}
							}
						}
					};

					nameLabel.SetBinding (Label.TextProperty, "Name");
					birthdayLabel.SetBinding (Label.TextProperty, new Binding ("Birthday", BindingMode.OneWay, null, null, "Born {0:d}"));
					boxView.SetBinding (BoxView.ColorProperty, "FavoriteColor");
					stack.SetBinding (BackgroundColorProperty, "BackgroundColor");

					return new ViewCell {
						View = stack
					};
				})
			};

			buttonAdd.Clicked += (sender, e) =>
			{
				var person = new Person (string.Format ("Name {0}", _count++), DateTime.Today, Color.Blue);

				people.Add (person);

				listView.ScrollTo (person, ScrollToPosition.End, true);

			};

			buttonRemove.Clicked += (sender, e) => people.RemoveAt (people.Count - 1);

			buttonScrollToBottom.Clicked += (sender, e) =>
			{
				var person = people[people.Count - 1];

				listView.ScrollTo (person, ScrollToPosition.End, true);
			};

			Padding = new Thickness (10, Device.OnPlatform (20, 0, 0), 10, 5);

			Content = new StackLayout {
				Orientation = StackOrientation.Vertical,
				Children = {
					buttonStack,
					listView,
				}
			};
		}
	
#if UITEST
		[Test]
		[UiTest (typeof(ListView), "ScrollTo")]
		public void Issue2259Tests ()
		{
			for (int i = 0; i < 20; i++) {
				RunningApp.Tap (q => q.Button ("Add"));
				RunningApp.WaitForElement (q => q.Marked ("Name " + (i + 1).ToString ()));
				RunningApp.Screenshot ("Added Cell");
			}
		}
#endif
	}
}