Question about custom render TextCell Android

Hi , i was trying to create a custom render for TextCel on Androidl, and i have a issue that i don't know if it's a bug or not..

Sometimes the contentView property is null , and i can't get the base view . When i run this code, i see that some cells have the custom font (the ones where contentView wasn't null) but the others no, since i m create a BaseCell when contentView is null and not putting the text, i would aspect to see no text on that cells. I thinks this is because we are reusing cells, but still i needed some help on this one.

Thanks

heres the code for the render in Android:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Xamarin.Forms.Platform.Android;
using Xamarin.Forms;
using Android.Graphics;
using XForms.Toolkit.Controls;
using XForms.Toolkit.Droid;

[assembly: ExportRenderer (typeof (ExtendedTextCell), typeof (ExtendedTextCellRenderer))]
namespace XForms.Toolkit.Droid
{
    public class ExtendedTextCellRenderer :  Xamarin.Forms.Platform.Android.TextCellRenderer
    {
        public ExtendedTextCellRenderer (){}
        private Context _context;

        protected override void OnCellPropertyChanged (object sender, System.ComponentModel.PropertyChangedEventArgs args)
        {
            base.OnCellPropertyChanged (sender, args);
        }
        protected override Android.Views.View GetCellCore (Cell item, Android.Views.View convertView, ViewGroup parent, Context context)
        {
            _context = context;

            var view = (ExtendedTextCell)item;
            if (convertView == null) {
                convertView = new BaseCellView (context);
            } 
            var control = ((LinearLayout)convertView);

            var mainview = (TextView)(control.GetChildAt (1) as LinearLayout).GetChildAt (0);
            var detailview = (TextView)(control.GetChildAt (1) as LinearLayout).GetChildAt (1);

            UpdateUi (view, mainview);
            UpdateUi (view, detailview);
            return convertView;;
        }

        void UpdateUi (ExtendedTextCell view, TextView control)
        {
            if (!string.IsNullOrEmpty (view.FontName)) {
                control.Typeface =  TrySetFont (view.FontName);
            }
            if (!string.IsNullOrEmpty (view.FontNameAndroid)) {
                control.Typeface =  TrySetFont (view.FontNameAndroid);;
            }
            if (view.FontSize > 0)
                control.TextSize = (float)view.FontSize;
         }

        private Typeface TrySetFont (string fontName)
        {
            Typeface tf = Typeface.Default;
            try {
                tf = Typeface.CreateFromAsset (_context.Assets,fontName);
                return tf;
            }
            catch (Exception ex) {
                Console.Write ("not found in assets {0}", ex);
                try {
                    tf = Typeface.CreateFromFile (fontName);
                    return tf;
                }
                catch (Exception ex1) {
                    Console.Write (ex1);
                    return Typeface.Default;
                }
            }
        }
    }
}