NotifyDataSetChanged没有更新我的ListView

NotifyDataSetChanged（）不会更新ListView，即使我正在重新读取序列化的xml文件。它只有在再次调用oncreate之后才会更新。读了一些Java代码，它告诉我重新填充我的listadapter，但这仍然不起作用。有什么想法吗？

public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
            {
                View view = inflater.Inflate(Resource.Layout.Card, null);
                listView = view.FindViewById<ListView>(Resource.Id.cardListView);
                return view;
            }

            public override void OnResume()
            {
                base.OnResume();
                List<string> nameList = new List<string>();
                string documentsPath = Android.OS.Environment.ExternalStorageDirectory + "/Gate";
                var cardPath = Path.Combine(documentsPath, "card.xml");
                if (File.Exists(cardPath))
                {
                    XmlSerializer serializer = new XmlSerializer(typeof(List<Card>));
                    StreamReader reader = new StreamReader(cardPath);
                    cardList = (List<Card>)serializer.Deserialize(reader);
                    reader.Close();
                }
                else
                {
                    cardList = new List<Card>();
                }
                foreach (Card card in cardList)
                {
                    nameList.Add(card.name);
                }
                var adapter = new ArrayAdapter<string>(this.Activity, Android.Resource.Layout.SimpleListItem1, nameList);
                listView.Adapter = adapter;
                adapter.NotifyDataSetChanged();
            }