[Bug] iOS - ListView and CollectionView - Editor - Focus is not cleared when Editor gets out of View

[BrayanKhosravian]

Description

When a Editor is placed inside a ViewCell and the Editor is currently focused while getting out of View, then the ViewCell.OnDisappearing is not called and the focus of the Editor is not cleared.

There are a few issues with this behavior:
1.) there is not always a "Done" button for an editor (f.e. NumberKeyboard)
2.) When he user scrolls down in a listview/collectionview the user can edit still the field even when it is not visible anymore
3.) i cant even workaround it as the OnDisappearing is not called at all when the editor is located inside a viewcell (The workaround would be to unfocus the editor in the ondisappearing)
4.) It causes weird rendering issues.

• For the listview the editor is visible at an index where it shouldnt.
• for the collectionView the editor is white or transparent and cant be used anymore.

Steps to Reproduce

ListView:

1. Copy and paste the snippet
2. Make sure that u use the ListView (Content = CreateListView();)
3. Start the app
4. Click the first editor
5. Set the Breakpoint in the OnDisappearing
6. Scroll
   => Editor is not unfocused
   => OnDisappearing is not called where the currently focused editor is located

CollectionView:

1. Copy and paste the snippet
2. Make sure that u use the CollectionView (Content = CreateCollectionView();) (It is commented, please uncomment it)
3. Start the app
4. Click the first editor
5. Scroll
   => Editor is not unfocused
   => OnDisappearing is not called where the currently focused editor is located

Code is added to "Repro Link"

Expected Behavior

The Editor should unfocus when its not visible anymore.
ListView: The OnDisappearing of the viewcell should be called when getting out of view even when a focused Editor is locaed inside.

Actual Behavior

Editor is not unfocused
ListView: OnDisappearing is not called

Basic Information

• Version with issue: master
• Last known good version: -
• IDE: VS 2019
• Platform Target Frameworks:
  • iOS: tested on xamarin forms master branch

Screenshots

Reproduction Link

using System.Collections.ObjectModel;
using System.Linq;
using Xamarin.Forms.CustomAttributes;

namespace Xamarin.Forms.Controls.Issues
{
	[Issue(IssueTracker.Github, 10942, "iOS - ListView and CollectionView - Editor - Focus is not cleared when Editor gets out of View", PlatformAffected.iOS)]
	public class IosEntryOnDisappearing : TestContentPage
	{
		private class EditorContentView : ContentView
		{
			public EditorContentView()
			{
				var editor = new Editor();
				editor.SetBinding(Editor.TextProperty, ".");
				Content = editor;
			}
		}

		private class EditorViewCell : ViewCell
		{
			public EditorViewCell()
			{
				var editor = new Editor();
				editor.SetBinding(Editor.TextProperty, ".");
				View = editor;
			}

			// Click on the first Cell/View and then scroll down
			// You notice that the OnDisappearing is not called for the cell where the editor is located
			protected override void OnDisappearing()
			{
				var text = (View as Editor)?.Text;
				base.OnDisappearing(); // breakpoint here

			}
		}

		protected override void Init()
		{
			// comment one of the 2 lines out // use either listview or collectionview
			// Content = CreateCollectionView();
			Content = CreateListView();
		}

		ListView CreateListView()
		{
			var listView = new ListView();
			listView.ItemTemplate = new DataTemplate(typeof(EditorViewCell));
			listView.ItemsSource = GetSource();
			return listView;
		}

		CollectionView CreateCollectionView()
		{
			var collectionView = new CollectionView();
			collectionView.ItemTemplate = new DataTemplate(typeof(EditorContentView));
			collectionView.ItemsSource = GetSource();
			return collectionView;
		}

		ObservableCollection<int> GetSource() => 
			new ObservableCollection<int>(Enumerable.Range(0, 75));
	}
}

Workaround

none

[BrayanKhosravian]

@gentledepp @bruzkovsky fyi

[rmarinho]

Can confirm this issue on iOS, on Android the Keyboard is hidden when we scroll, so we should make the same on iOS. At the same time is weird that only the cell that is focused doesn't call Disappearing, the others the Disappearing is being called.