如何计算购物车 JList 中商品价格的总和？

huangapple
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英文:

How to calculate the sum of prices in a cart JList?

问题

我一直在创建这个库存程序，它从一个txt文件中获取产品ID、名称、物品价格和库存。它将其导入到我的产品列表（JList），然后当我按下“添加到购物车”按钮时，它会将所选产品移动到购物车（另一个JList）。

我的主要问题是，如何计算购物车中所有价格的总和？如何将产品项的价格与特定价格绑定？假设为了显示总价格，我正在使用一个JLabel。

以下是一些图片和代码：

这是当前“移动”按钮的代码：

  1. public void actionPerformed(ActionEvent e) {
  2.     if (e.getSource() == movebutton) {
  3.         model2.addElement(list.getSelectedValue());
  4.     }
  5. }

这是显示图像、物品名称、价格和库存的代码：

  1. public void valueChanged(ListSelectionEvent e) {
  2.     try {
  3.         String gadgets = (String) c1.getSelectedItem();  //当选择下拉框时
  4.         switch (gadgets) {
  5.             case "Consoles":  //选择第一个产品类别
  6.                 image.setIcon(graphicsconsole[list.getSelectedIndex()]);  //设置图像
  8.                 File file = new File("stock\\consoles\\consoles.txt"); //读取txt文件 
  9.                 int ctr = 0;
  10.                 try {
  11.                     Scanner s1 = new Scanner(new File(String.valueOf(file)));
  12.                     while (s1.hasNextLine()) {
  13.                         ctr = ctr + 1;
  14.                         s1.next();
  15.                         s1.next();
  16.                         s1.next();
  17.                         s1.nextLine();
  18.                     }
  19.                     String[] ID = new String[ctr];
  20.                     String[] PRICE = new String[ctr];
  21.                     String[] STOCK = new String[ctr];
  22.                     String[] NAME = new String[ctr];
  24.                     Scanner s2 = new Scanner(new File(String.valueOf(file)));  //创建字符串
  25.                     for (int i = 0; i < ctr; i = i + 1) {
  26.                         ID[i] = s2.next();
  27.                         PRICE[i] = s2.next();
  28.                         STOCK[i] = s2.next();
  29.                         NAME[i] = s2.nextLine();
  31.                         iteminfo.setText(NAME[list.getSelectedIndex()]);  //显示物品名称
  32.                         itemdescription.setText(" P " + PRICE[list.getSelectedIndex()]);  //显示价格
  33.                         itemstock.setText(" Stock: "+ STOCK[list.getSelectedIndex()]); //显示库存
  34.                     }
  35.                 } catch (Exception a) {
  36.                     a.printStackTrace();
  37.                 }
  38.                 break;
  39.         }
  40.     } catch (Exception ex) {
  41.         ex.printStackTrace();
  42.     }
  43. }

我是否需要一个空数组并在其中添加值？如何在购物车中不存在时删除值？如果我的帖子/问题听起来令人困惑，我很抱歉，我希望它是可以理解的。

英文:

I have been creating this inventory program that gets the product ID, name, item price and stocks from a txt file. It imports it to my product list (JList), then when I press the "add to cart" button, it will then move the selected product to the Cart (which is another JList).

My main question is, how can I calculate the sum of all of the prices in the Cart? How do I bind the prices of the product items with a specific price? Assuming that to show the total price, I'm using a JLabel.

Here are some pictures and code:

My inventory program

This is the code for the move button as of now:

  1. public void actionPerformed(ActionEvent e) {
  2.     if (e.getSource() == movebutton) {
  3.     model2.addElement(list.getSelectedValue());
  5.     }

This is the code to show the images, item name, price and stock of an item:

  1. public void valueChanged(ListSelectionEvent e) {
  2.     try {
  3.         String gadgets = (String) c1.getSelectedItem();  //when the combobox is selected
  4.         switch (gadgets) {
  5.             case &quot;Consoles&quot;:  //selects first product category
  6.                 image.setIcon(graphicsconsole[list.getSelectedIndex()]);  //sets the image
  8.                 File file = new File(&quot;stock\\consoles\\consoles.txt&quot;); //reads the txt file 
  9.                 int ctr = 0;
  10.                 try {
  11.                     Scanner s1 = new Scanner(new File(String.valueOf(file)));
  12.                     while (s1.hasNextLine()) {
  13.                         ctr = ctr + 1;
  14.                         s1.next();
  15.                         s1.next();
  16.                         s1.next();
  17.                         s1.nextLine();
  18.                     }
  19.                     String[] ID = new String[ctr];
  20.                     String[] PRICE = new String[ctr];
  21.                     String[] STOCK = new String[ctr];
  22.                     String[] NAME = new String[ctr];
  24.                     Scanner s2 = new Scanner(new File(String.valueOf(file)));  //creates strings
  25.                     for (int i = 0; i &lt; ctr; i = i + 1) {
  26.                         ID[i] = s2.next();
  27.                         PRICE[i] = s2.next();
  28.                         STOCK[i] = s2.next();
  29.                         NAME[i] = s2.nextLine();
  31.                 iteminfo.setText(NAME[list.getSelectedIndex()]);  //shows the item name
  32.                 itemdescription.setText(&quot; P &quot; + PRICE[list.getSelectedIndex()]);  //shows the price
  33.                 itemstock.setText(&quot; Stock: &quot;+ STOCK[list.getSelectedIndex()]); //shows the stock
  34.                     }
  35.                 } catch (Exception a) {
  36.                     a.printStackTrace();
  37.                 }break;

Do I need to have an empty array and add the values there? How do I also remove values when it is not in the cart? Sorry if my post/question sounds confusing, I hope that it is understandable.

huangapple
  • 本文由 发表于 2020年4月8日 14:28:16
  • 转载请务必保留本文链接：https://java.coder-hub.com/61094537.html
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