Ooui-tws-port/Ooui.Forms/Renderers/ListViewRenderer.cs

using Ooui.Forms.Extensions;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using Xamarin.Forms;
using Xamarin.Forms.Internals;

namespace Ooui.Forms.Renderers
{
    public class ListViewRenderer : ViewRenderer<ListView, List>
    {
        private bool _disposed;
        private List _listView;
        private List<ListItem> _cells;

        public ListViewRenderer()
        {
            _cells = new List<ListItem>();
        }

        ITemplatedItemsView<Cell> TemplatedItemsView => Element;

        protected override void OnElementChanged(ElementChangedEventArgs<ListView> e)
        {
            if (e.NewElement != null)
            {
                if (Control == null)
                {
                    _listView = new List();

                    SetNativeControl(_listView);
                }

                UpdateItems();
                UpdateBackgroundColor();
            }

            base.OnElementChanged(e);
        }

        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            base.OnElementPropertyChanged(sender, e);

            if (e.PropertyName == ListView.ItemsSourceProperty.PropertyName)
                UpdateItems();
        }

        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);

            if (disposing && !_disposed)
            {
                _disposed = true;
            }
        }

        private void UpdateItems()
        {
            _cells.Clear();

            var items = TemplatedItemsView.TemplatedItems;

            if (!items.Any())
            {
                return;
            }

            bool grouping = Element.IsGroupingEnabled;

            if (grouping)
            {
                return;
            }

            foreach (var item in items)
            {
                var cell = GetCell(item);

                var listItem = new ListItem();
                listItem.Style["list-style-type"] = "none";

                listItem.AppendChild(cell);

                _cells.Add(listItem);
            }

            foreach (var cell in _cells)
            {
                _listView.AppendChild(cell);
            }
        }

        private void UpdateBackgroundColor()
        {
            var backgroundColor = Element.BackgroundColor.ToOouiColor();

            _listView.Style.BackgroundColor = backgroundColor;
        }

        private Div GetCell(Cell cell)
        {
            var renderer =
                (Cells.CellRenderer)Registrar.Registered.GetHandler<IRegisterable>(cell.GetType());

            var realCell = renderer.GetCell(cell, null, _listView);

            return realCell;
        }
    }
}