Java中JTable的两个单元格之间的乘法

Question

当我在“单位”和“价格”列的第一行的单元格中输入值时，“金额”列； 列的单元格值应该设置为单位和数量的乘积。 我应该使用哪个听众？ 请帮忙，因为我是Java新手。

码：

 JTable jTable1;
 DefaultTableModel mod=new DefaultTableModel();
        mod.addColumn("No");
        mod.addColumn("Item ID");
        mod.addColumn("Units");
        mod.addColumn("Amount");
        mod.addColumn("UOM");
        mod.addColumn("Delivery Date");
        mod.addColumn("Total Amount");
        mod.addColumn("Notes");
        mod.addColumn("Received");
        mod.addRow(new Object [][] {
            {1, null, null, null, null, null, null, null, null}
        });
        jTable1.setModel(mod);
        jTable1.setColumnSelectionAllowed(true);

Answer 1

这个想法是实现一个TableModel以便它自动返回单位和金额乘积的结果。 这是我的意思的一个小例子（要添加新行，只需双击表下方）：

import java.awt.BorderLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Vector;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;

public class TestTable3 {

    protected void initUI() {
        final DefaultTableModel model = new DefaultTableModel() {

            @Override
            public Class<?> getColumnClass(int columnIndex) {
                switch (columnIndex) {
                case 0:
                    return Integer.class;
                case 1:
                case 2:
                    return Double.class;
                }
                return super.getColumnClass(columnIndex);
            }

            @Override
            public Object getValueAt(int row, int column) {
                if (column == 2) {
                    Integer i = (Integer) getValueAt(row, 0);
                    Double d = (Double) getValueAt(row, 1);
                    if (i != null && d != null) {
                        return i * d;
                    } else {
                        return 0.0;
                    }
                }
                return super.getValueAt(row, column);
            }

            @Override
            public boolean isCellEditable(int row, int column) {
                return column == 0 || column == 1;
            }

            @Override
            public void setValueAt(Object aValue, int row, int column) {
                super.setValueAt(aValue, row, column);
                fireTableCellUpdated(row, 2);
            }

            @Override
            public String getColumnName(int column) {
                switch (column) {
                case 0:
                    return "Quantity";
                case 1:
                    return "Price";
                case 2:
                    return "Total";
                }
                return super.getColumnName(column);
            }

            @Override
            public int getColumnCount() {
                return 3;
            }
        };
        final JTable table = new JTable(model);
        table.setFillsViewportHeight(true);
        table.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                if (e.getClickCount() == 2) {
                    if (table.rowAtPoint(e.getPoint()) < 0) {
                        model.addRow(new Vector());
                    }
                }
            }
        });
        model.addRow(new Vector());
        JFrame frame = new JFrame(TestTable3.class.getSimpleName());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JScrollPane scrollpane = new JScrollPane(table);
        frame.add(scrollpane, BorderLayout.CENTER);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException,
            UnsupportedLookAndFeelException {
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new TestTable3().initUI();
            }
        });
    }

}

结果：

Answer 2

当我在“单位”和“价格”列的第一行的单元格中输入值时，“金额”列； 列单元格值应设置为单位和金额的乘积

• 看一下TableModelListener

• 必须阅读Oracle JTable教程