Question

我正在通过Xamarin开发基本的Android应用程序，我在List中使用ListItem在Adapter中设置。但是当我删除或编辑任何项目时，listview不会刷新自己。我知道ObservableCollection，但我不知道如何将它与适配器一起使用。有谁可以帮助我吗？我是Xamarin的新人。

适配器：

public class MealsAdapter : BaseAdapter<Meal>
{
    List<Meal> items;
    Activity context;

    public MealsAdapter(Activity context, List<Meal> items)
        : base()
    {
        this.context = context;
        this.items = items;
    }

    public override Meal this[int position]
    {
        get
        {
            return items[position];
        }
    }

    public override int Count
    {
        get
        {
            return items.Count;
        }
    }

    public override long GetItemId(int position)
    {
        return position;
    }

    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        var item = items[position];

        View view = convertView;
        if (view == null)
            view = context.LayoutInflater.Inflate(Resource.Layout.MealListItem, null);
        view.FindViewById<TextView>(Resource.Id.textViewNazev).Text = item.Name;
        view.FindViewById<TextView>(Resource.Id.textViewBilkoviny).Text = context.Resources.GetString(Resource.String.BilkovinyNadpis) + ": " + item.Bilkoviny.ToString();
        view.FindViewById<TextView>(Resource.Id.textViewSacharidy).Text = context.Resources.GetString(Resource.String.SacharidyNadpis) + ": " + item.Sacharidy.ToString();

        return view;
    }
}

的ListView：

ListView listView;     
protected override void OnCreate(Bundle savedInstanceState)
            {
                base.OnCreate(savedInstanceState);
                SetContentView(Resource.Layout.MealsSettings);

                listView = FindViewById<ListView>(Resource.Id.listViewJidlo);

                listView.Adapter = new MealsAdapter(this, DataStorage.meallist);
                listView.ItemClick += ListView_ItemClick;
            }

DataStorage.meallist是简单的List。我已经尝试将ObservableCollection放到适配器和DataStorage.meallist中，但它提供了帮助。

Answer 1

您需要致电NotifyDataSetChanged()让ListView知道其收藏集已更改。

无论您何时删除/删除List<Meal> items中的项目，请确保随后致电NotifyDataSetChanged()。

Android Xamarin - 带ObservableCollection的

1 个答案: