如何对ListView的TextCell by按钮进行聚焦？

using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

[assembly: ExportRenderer(typeof(TextCell), typeof(CustomTextCellRenderer))]
namespace YourNamespace
{
    public class CustomTextCellRenderer : TextCellRenderer
    {
        protected override Android.Views.View GetCellCore(Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context)
        {
            var cellView = base.GetCellCore(item, convertView, parent, context);

            var textCell = (TextCell)item;
            if (textCell.Command != null)
            {
                cellView.Focusable = true;
                cellView.FocusableInTouchMode = true;
                cellView.Clickable = true;
                cellView.Click += (sender, e) =>
                {
                    textCell.Command.Execute(null);
                };
            }

            return cellView;
        }
    }
}