如何添加用户将项目数量指定到GUI中？

Question

基本上我想创建一个GUI，允许用户从给定列表中选择一个项目，然后显示添加项目的总金额，即价格。因此，它将是物品的数量*价格。数量将从用户输入。到目前为止，这是代码，我想以用户输入数量的方式修改代码，它将在GUI中进行整体计算和显示。

如何添加用户将项目数量指定到GUI中？

班级Item

public class Item {

private String itemName;
private Integer itemPrice;

public Item(){}
public Item(String itemName, int itemPrice){
    this.itemName = itemName;
    this.itemPrice = itemPrice;
}
public String getItemName() {
    return itemName;
}
public void setItemName(String itemName) {
    this.itemName = itemName;
}
public Integer getItemPrice() {
    return itemPrice;
}
public void setItemPrice(Integer itemPrice) {
    this.itemPrice = itemPrice;
}
@Override

public String toString(){
    return this.itemName;
}
}

班级ShoppingCart

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import javax.swing.*;

public class ShoppingCart extends JFrame {
    private JList leftlist;
    private JList rightlist;
    private JButton addbutton;
    private JButton totalbutton;
    private JLabel totalLabel;


public ShoppingCart() {

    super("Shopping Cart");
    setLayout(new FlowLayout());

    // preparing item list it might be coming from somewhere else
    List<Item> itemList = new ArrayList<Item>();
    itemList.add(new Item("Apple", 10));
    itemList.add(new Item("Carrot", 40));
    itemList.add(new Item("Cucumber", 50));
    itemList.add(new Item("Iphone 6", 6000));
    itemList.add(new Item("Galaxy S6", 1100));
    itemList.add(new Item("BlackBerry", 1300));
    itemList.add(new Item("HairDryer", 200));
    itemList.add(new Item("Ironer", 300));
    itemList.add(new Item("Vacuum Cleaner", 400));

    leftlist = new JList(itemList.toArray());
    leftlist.setVisibleRowCount(5);
    leftlist
            .setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
    add(new JScrollPane(leftlist));

    addbutton = new JButton("ADD");
    addbutton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent event) {
            //make sure you preserve the previously selected list items
            int size = rightlist.getModel().getSize();
            Set objects = new LinkedHashSet();
            for (int i = 0; i < size; i++) {
                objects.add(rightlist.getModel().getElementAt(i));
            }
            objects.addAll(Arrays.asList(leftlist.getSelectedValues()));

            rightlist.setListData(objects.toArray());
        }
    });
    add(addbutton);

    rightlist = new JList();
    rightlist.setVisibleRowCount(5);
    rightlist.setFixedCellWidth(55);
    rightlist.setFixedCellHeight(20);
    add(new JScrollPane(rightlist));

    totalbutton = new JButton("Total");
    totalbutton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent event) {
            // iterate over item objects and calculate the total
            int size = rightlist.getModel().getSize();
            Integer totalAmount = 0;
            for (int i = 0; i < size; i++) {
                Object obj = leftlist.getModel().getElementAt(i);
                Item item = (Item) obj;
                totalAmount += item.getItemPrice();
            }
            //update the total Amount label
            totalLabel.setText("Total Amount : " + totalAmount);
        }
    });
    add(totalbutton);

    totalLabel = new JLabel("Total Amount : ");

    add(totalLabel);

}

public static void main(String[] args) {
    ShoppingCart list = new ShoppingCart();
    list.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    list.setSize(300, 300);
    list.setVisible(true);
}
}

Answer 1

这基本上是库存的场景.. 首先你应该提示用户从列表中选择一个项目然后在焦点出价格字段应该根据产品名称自动获取文本.. 用户将输入数量..然后使用以下代码计算总价...

 private void total_buttonActionPerformed(java.awt.event.ActionEvent evt) {                                             


        float price=Float.parseFloat(price_txt.getText());
        float quantity=Float.parseFloat(quantity_txt.getText());
        float sum=price*quantity;
        total_txt.setText(""+sum);

}             

//注意库存，您还应该检查产品的可用性..

private void quantity_txtFocusLost(java.awt.event.FocusEvent evt) {                                       
    int quantity=Integer.parseInt(quantity_txt.getText());
    int available=Integer.parseInt(availability_txt.getText());
    if(quantity>available)
    {
        JOptionPane.showMessageDialog(rootPane, "Entered quantity is unavailable.");
        quantity_txt.requestFocus();
    }

}