在Spinner OnItemSelected中索引超出范围的异常

Question

我在listview中有一个微调器。

适用于列表的适配器

listQuantities = database.getItemQuantities(id);
Log.d("List size", listQuantities.size()); //getting 2 in first row
QuantityArrayAdapter adapter = new QuantityArrayAdapter(context, R.layout.spinner_item_black, listQuantities);
spQuantity.setAdapter(adapter);
spQuantity.setOnItemSelectedListener(new OnItemSelectedListener() {

            @Override
            public void onItemSelected(AdapterView<?> arg0, View arg1,
                    int arg2, long arg3) {
                // TODO Auto-generated method stub
                listQuantities = database.getItemQuantities(id);
                Log.d("size", listQuantities.size()); //getting only one in first row
                Quantity selectedQuantity = listQuantities.get(arg2); //index out of bound

            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {
                // TODO Auto-generated method stub

            }
        });

适用于微调器的适配器

@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
    View rowView = convertView;
    if (rowView == null) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        rowView = inflater
                .inflate(R.layout.spinner_quantity, parent, false);
    }
    Quantity quantity = quantities.get(position);

    TextView tvQuantity = (TextView) rowView.findViewById(R.id.textView1);
    tvQuantity.setText(quantity.toString());

    return rowView;
}

锭床工人已正确填充。但是在选择项目时，它会显示索引超出范围。