我對購物車中單件商品的總價更新錯誤。如果我增加數量并減少數量，則會發生以下情況：增加數量1=4,10；2=4,10；3=8,20；4=12,30；減少數量：從 4(16,30) 到 3 = 16,40；2 = 12,30；1=8,20；但所有物品的總價格是正確的。public class CartAdapter extends RecyclerView.Adapter<CartViewHolder> {private List<Order> listData = new ArrayList<>();private Cart cart;public CartAdapter(List<Order> listData, Cart cart) {    this.listData = listData;    this.cart = cart;}@NonNull@Overridepublic CartViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {    LayoutInflater inflater = LayoutInflater.from(cart);    View itemView = inflater.inflate(R.layout.cart_layout, parent, false);    return new CartViewHolder(itemView);}@Overridepublic void onBindViewHolder(@NonNull final CartViewHolder holder, final int position) {    holder.btn_quantity.setNumber(listData.get(position).getQuantity());    holder.btn_quantity.setOnValueChangeListener(new ElegantNumberButton.OnValueChangeListener() {        @Override        public void onValueChange(ElegantNumberButton view, int oldValue, int newValue) {            Locale locale = new Locale("de", "DE");            NumberFormat fmt = NumberFormat.getCurrencyInstance(locale);            double price = (Double.parseDouble(listData.get(position).getPrice()))*(Double.parseDouble(listData.get(position).getQuantity()));            //int price = (Integer.parseInt(listData.get(position).getPrice()))*(Integer.parseInt(listData.get(position).getQuantity()));            holder.txt_price.setText(fmt.format(price));            holder.txt_cart_name.setText(listData.get(position).getProductName());        }    });