1 files changed, 131 insertions, 0 deletions

diff --git a/Xamarin.Forms.Platform.Android/Cells/CellRenderer.cs b/Xamarin.Forms.Platform.Android/Cells/CellRenderer.cs
new file mode 100644
index 00000000..d9d4eee5
--- /dev/null
+++ b/Xamarin.Forms.Platform.Android/Cells/CellRenderer.cs
@@ -0,0 +1,131 @@
+using System;
+using System.ComponentModel;
+using Android.Content;
+using Android.Views;
+using Android.Widget;
+using AView = Android.Views.View;
+using Object = Java.Lang.Object;
+
+namespace Xamarin.Forms.Platform.Android
+{
+	public class CellRenderer : IRegisterable
+	{
+		static readonly PropertyChangedEventHandler PropertyChangedHandler = OnGlobalCellPropertyChanged;
+
+		static readonly BindableProperty RendererProperty = BindableProperty.CreateAttached("Renderer", typeof(CellRenderer), typeof(Cell), null);
+
+		EventHandler _onForceUpdateSizeRequested;
+
+		public View ParentView { get; set; }
+
+		protected Cell Cell { get; set; }
+
+		public AView GetCell(Cell item, AView convertView, ViewGroup parent, Context context)
+		{
+			Performance.Start();
+
+			Cell = item;
+			Cell.PropertyChanged -= PropertyChangedHandler;
+
+			SetRenderer(Cell, this);
+
+			if (convertView != null)
+			{
+				Object tag = convertView.Tag;
+				var renderHolder = tag as RendererHolder;
+				if (renderHolder != null)
+				{
+					Cell oldCell = renderHolder.Renderer.Cell;
+					oldCell.SendDisappearing();
+
+					if (Cell != oldCell)
+						SetRenderer(oldCell, null);
+				}
+			}
+
+			AView view = GetCellCore(item, convertView, parent, context);
+
+			WireUpForceUpdateSizeRequested(item, view);
+
+			var holder = view.Tag as RendererHolder;
+			if (holder == null)
+				view.Tag = new RendererHolder { Renderer = this };
+			else
+				holder.Renderer = this;
+
+			Cell.PropertyChanged += PropertyChangedHandler;
+			Cell.SendAppearing();
+
+			Performance.Stop();
+
+			return view;
+		}
+
+		protected virtual AView GetCellCore(Cell item, AView convertView, ViewGroup parent, Context context)
+		{
+			Performance.Start();
+
+			LayoutInflater inflater = LayoutInflater.FromContext(context);
+			const int type = global::Android.Resource.Layout.SimpleListItem1;
+			AView view = inflater.Inflate(type, null);
+
+			var textView = view.FindViewById<TextView>(global::Android.Resource.Id.Text1);
+			textView.Text = item.ToString();
+			textView.SetBackgroundColor(global::Android.Graphics.Color.Transparent);
+			view.SetBackgroundColor(global::Android.Graphics.Color.Black);
+
+			Performance.Stop();
+
+			return view;
+		}
+
+		protected virtual void OnCellPropertyChanged(object sender, PropertyChangedEventArgs e)
+		{
+		}
+
+		protected void WireUpForceUpdateSizeRequested(Cell cell, AView nativeCell)
+		{
+			cell.ForceUpdateSizeRequested -= _onForceUpdateSizeRequested;
+
+			_onForceUpdateSizeRequested = delegate
+			{
+				// RenderHeight may not be changed, but that's okay, since we
+				// don't actually use the height argument in the OnMeasure override.
+				nativeCell.Measure(nativeCell.Width, (int)cell.RenderHeight);
+				nativeCell.SetMinimumHeight(nativeCell.MeasuredHeight);
+				nativeCell.SetMinimumWidth(nativeCell.MeasuredWidth);
+			};
+
+			cell.ForceUpdateSizeRequested += _onForceUpdateSizeRequested;
+		}
+
+		internal static CellRenderer GetRenderer(BindableObject cell)
+		{
+			return (CellRenderer)cell.GetValue(RendererProperty);
+		}
+
+		internal static void SetRenderer(BindableObject cell, CellRenderer renderer)
+		{
+			cell.SetValue(RendererProperty, renderer);
+		}
+
+		static void OnGlobalCellPropertyChanged(object sender, PropertyChangedEventArgs e)
+		{
+			var cell = (Cell)sender;
+			CellRenderer renderer = GetRenderer(cell);
+			if (renderer == null)
+			{
+				cell.PropertyChanged -= PropertyChangedHandler;
+				return;
+			}
+
+			renderer.OnCellPropertyChanged(sender, e);
+			;
+		}
+
+		class RendererHolder : Object
+		{
+			public CellRenderer Renderer;
+		}
+	}
+}
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