Question

每当我再次点击按钮时，我想更新数量和价格，但它不起作用。我的代码中有什么问题吗？我尝试了一切。我正在创建一个简单的销售点系统，用户只需单击按钮即可添加菜单并自动进行计算。我为调节添加了增量。

你有什么想法吗？

package sampletable;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.List.*;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class SampleTable extends JFrame
{

    Container con;
    JPanel pane1,pane2;
    JButton btn1;

    JTable JT;
    String[] columns = {"Menu","Price","Quantity"};
    String[][] data = new String[0][0];
    Object [] row1 = new Object[3];
    DefaultTableModel model = new DefaultTableModel();

    int price1=0;
    int price1Mul;
    int Clicks1=0;
    public SampleTable()
    {
        con = getContentPane();
        con.setLayout(new GridLayout(2,1));

        pane1 = new JPanel();
        btn1 = new JButton("Food 1");
        btn1.addActionListener(new btnAction1());
        pane1.add(btn1);
        con.add(pane1);

        model.setDataVector(data, columns);
        JT = new JTable();
        JT.setPreferredScrollableViewportSize(new Dimension(200,200));
        JT.setFillsViewportHeight(true);
        JT.setModel(model);

        JScrollPane JPS = new JScrollPane(JT);
        con.add(JPS);
        pane2 = new JPanel();
        con.add(pane2);    
    }
    /*In here I want to change the value thats why I use incrementation so 
    that the next click it would increment and satisfy the other if.*/

    public class btnAction1 implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
            {
            price1 = 20;
            price1Mul++;
            if (Clicks1 == 0)
            {
            row1[0] ="Food1";
            row1[1] =price1;
            row1[2] =price1Mul;
            model.addRow(row1);
            int x =  price1 * price1Mul;
            price1 = x;
            Clicks1++;
            }

            else if (Clicks1 == 1)
            {
                int addPrice = price1 * price1Mul;
                row1[0] ="Food1";
                row1[1] =addPrice;
                row1[2] =price1Mul;
            }
            }
    }
//Main Class
public static void main(String[] args) 
{
 SampleTable ST = new SampleTable();
 ST.setTitle("Sample JTable");
 ST.setSize(500,500);
 ST.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 ST.setVisible(true);
 ST.setResizable(false);
}
}

Answer 1

您需要将model.addRow(row1)放在if / else块之外，才能将该行添加到模型中，无论该按钮是否被点击。如果要更新上次添加的行，只需按removeRow(int row)删除它，然后插入更新的行，如前所述。

public void actionPerformed(ActionEvent e) {
        price1 = 20;
        price1Mul++;
        if (Clicks1 == 0) {
            row1[0] = "Food1";
            row1[1] = price1;
            row1[2] = price1Mul;
            int x = price1 * price1Mul;
            price1 = x;
            Clicks1++;
        } else if (Clicks1 == 1) {
            int lasRowAdded = model.getRowCount() - 1;
            model.removeRow(lastRowAdded);
            int addPrice = price1 * price1Mul;
            row1[0] = "Food1";
            row1[1] = addPrice;
            row1[2] = price1Mul;
        }
        model.addRow(row1);
    }

更新DefaultTableModel中的行数据

1 个答案: