滚动

Question

我正在使用Xamarin Android写作，而我正试图处理ListView中的滚动问题。当我向下滚动时，再向上一次EditText失去先前输入的值。我用ViewHolder模式编写了自定义适配器。不幸的是，我的适配器无法正常工作，它将输入的数据混合到随机（？）行。

这是我的适配器。有人能告诉我代码中的问题在哪里吗？

public class Adapter: BaseAdapter<Product>
{

   private List<Product> MyItems;
   private Context MyContext;
   public string[] Current;
   Dictionary<int, string> myDictionary = new Dictionary<int, string>();

   public Adapter(Context context, List<Product> items)
   {
       MyContext = context;
       MyItems = items;
        Current = new string[items.Count];
       for (int i = 0; i < items.Count; i++)
       {
           myDictionary.Add(i, "0");

       }

   }
    public override Product this[int position]
    {
        get { return MyItems[position]; }
    }

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

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

    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View row = convertView;
        ViewHolder holder = null;
        int nPostion = position;

        if (row == null)
        {
            row = LayoutInflater.From(MyContext).Inflate(Resource.Layout.productRowOrder, parent, false);
            holder = new ViewHolder();
            holder.tv1 =row.FindViewById<TextView>(Resource.Id.productOrderId);
            holder.tv1.Text = "" + MyItems[position].id;
            holder.tv2 =row.FindViewById<TextView>(Resource.Id.productOrderName);
            holder.tv2.Text = MyItems[position].name;
            holder.tv3 =row.FindViewById<TextView>(Resource.Id.productOrderStock);
            holder.tv3.Text = "" + MyItems[position].quantity;
            holder.tv4 =row.FindViewById<TextView>(Resource.Id.productOrderUnit);
            holder.tv4.Text = "" + MyItems[position].unit;
            holder.tv5 =row.FindViewById<TextView>(Resource.Id.productOrderPriceNet);
            holder.tv5.Text = "" + MyItems[position].priceNet;
            holder.tv6 = row.FindViewById<TextView>(Resource.Id.productOrderPriceGross);
            holder.tv6.Text = "" + MyItems[position].priceGross;

            holder.et1 = row.FindViewById<EditText>(Resource.Id.productOrderQuantity);


            row.Tag = holder;
        }
        else
        {
            holder = (ViewHolder)row.Tag;
        }

        holder.et1.AfterTextChanged += (sender, args) =>
        {
            Current[holder.pos] = args.Editable.ToString();
            myDictionary[nPostion] = args.Editable.ToString().Trim();
        };



         holder.pos = position;

holder.et1.Text = myDictionary[position];


        return row;
    }

    private class ViewHolder : Java.Lang.Object
    {
        public TextView tv1;
        public TextView tv2;
        public TextView tv3;
        public TextView tv4;
        public TextView tv5;
        public TextView tv6;
        public EditText et1;
        public int pos;
    }
}
}

Answer 1

从代码中，此行holder.et1.Text = myDictionary[position];是滚动列表视图时设置edittext的值的位置。因此，数据源myDictionary很可能处于无序状态。这一行myDictionary[nPostion] = args.Editable.ToString().Trim();是我们将特定值放入edittext的地方。

我的解决方案是您可以尝试使用此行myDictionary[nPostion] = holder.et1.getText().ToString().Trim();而不是myDictionary[nPostion] = args.Editable.ToString().Trim();。（之前我没有使用过Xamarin，因此我使用了getText（）〜）。我希望这个改变对修复你的bug很有用。

Answer 2

不使用“AfterTextChanged”处理程序，而是处理“FocusChange”事件...... 它将解决您在Xamarin中的问题...

祝你好运。

---代码示例---

public override View GetView(int position, View convertView, ViewGroup parent)
{
        var row = convertView;

        if (row == null)
        {
            row = LayoutInflater.From(mContext).Inflate(Resource.Layout.StudentScore_item, null, false);
        }

        var lblScoreId = row.FindViewById<TextView>(Resource.Id.lblScoreID);
        lblScoreId.Text = mItems[position].ID.ToString();

        var tbxScore_Final = row.FindViewById<EditText>(Resource.Id.tbxScore_Final);
        tbxScore_Final.Typeface = fontType;
        tbxScore_Final.Text =
            (mItems[position].FinalScore.HasValue ? mItems[position].FinalScore.ToString() : "");
        tbxScore_Final.Tag = mItems[position].ID;
        tbxScore_Final.FocusChange += (sender, e) =>
        {
            EditText tbx = sender as EditText;
            decimal score;
            bool isValidScore = decimal.TryParse(tbx.Text, out score);
            if (isValidScore)
            {
                int inx = FindScoreIndex((int)tbx.Tag);

                Log.WriteLine(
                    LogPriority.Info,
                    "Infooo",
                    string.Format(
                        "INDEX = {0} | ID = {1} | DATA = {2} | Validated = {3} | ==> {4}",
                        inx,
                        tbx.Tag.ToString(),
                        tbx.Text,
                        score.ToString(),
                        mItems[inx].ID
                    )
                );

                mItems[inx].FinalScore = score;
            }
        };

        return row;
    }