java Swing对两列求和

Question

我用 Swing 制作了一个扩展 Jframe 的 GUI，我的 jtable 中有 6 列。我读取数据 从文本文件中，在第 4 列和第 5 列中有值 100 和 200，所以我希望当用户在第 4 列中编辑并将 160 而不是 100 第 5 列自动更改为 140 或用户 第 5 列中的编辑说 280 而不是 200 第 4 列自动更改为 20。这是我的代码。

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;

 public class Cs extends JFrame
    {
       private JTable table;
       private DefaultTableModel model;

    public Cs()
   {
      String aLine ;
      Vector columnNames = new Vector();
      Vector data = new Vector();

      try
      {
           FileInputStream fin = new FileInputStream("cs.txt");
           BufferedReader br = new BufferedReader(new InputStreamReader(fin));



           StringTokenizer st1 = new StringTokenizer(br.readLine(), " ");

           while( st1.hasMoreTokens() )
           {
                columnNames.addElement(st1.nextToken());
           }



           while ((aLine = br.readLine()) != null)
           {
                StringTokenizer st2 = new StringTokenizer(aLine, " ");
                Vector row = new Vector();

                while(st2.hasMoreTokens())
                {
                     row.addElement(st2.nextToken());
                }
                data.addElement( row );
           }
           br.close();
      }
      catch (Exception e)
      {
           e.printStackTrace();
      }



      model = new DefaultTableModel(data, columnNames);
      table = new JTable(model);

      JScrollPane scrollPane = new JScrollPane( table );
      getContentPane().add( scrollPane );
  }

 public static void main(String[] args)
    {
      Cs frame = new Cs();
      frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
      frame.pack();
      frame.setVisible(true);
     }

   }

Answer 1

覆盖 TableModel 的 setValueAt() 并根据更改更新另一列。这是示例。希望这会对你有所帮助。

JFrame frame = new JFrame("Summation of 2 columns");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

Object rows[][] = { { 100, 200 } };

String columns[] = { "Column 1", "Column 2" };

JTable table = new JTable(new DefaultTableModel(rows, columns) {
    private static final long serialVersionUID = 1L;

    public Class<? extends Object> getColumnClass(int column) {
        return getValueAt(0, column).getClass();
    }

    @Override
    public void setValueAt(Object object, int row, int column) {
        int changedValue = ((Integer) object).intValue();
        if (column == 0) {
            super.setValueAt(300 - changedValue, row, column + 1);
        } else if (column == 1) {
            super.setValueAt(300 - changedValue, row, column - 1);
        }
        super.setValueAt(object, row, column);
    }
});

JScrollPane pane = new JScrollPane(table);

frame.add(pane, BorderLayout.CENTER);

frame.setSize(200, 150);
frame.setVisible(true);

您必须按以下方式更改数据模型以满足您的要求。

替换你的模型

model = new DefaultTableModel(data, columnNames);

到

model = new DefaultTableModel(rows, columns) {
    private static final long serialVersionUID = 1L;

    public Class<? extends Object> getColumnClass(int column) {
        return getValueAt(0, column).getClass();
    }

    @Override
    public void setValueAt(Object object, int row, int column) {
        int changedValue = ((Integer) object).intValue();
        if (column == 2) {
            super.setValueAt(300 - changedValue, row, column + 1);
        } else if (column == 3) {
            super.setValueAt(300 - changedValue, row, column - 1);
       }
       super.setValueAt(object, row, column);
    }
};