java - JTable中的JComboBox显示无效数据

Question

我有一个JTable我根据数据库 select 动态填充其列询问。本栏目JTable将接受JComboBox 。现在，请看一下下面的代码。

private class ViewClientsDisplayData extends ComponentAdapter
     {
        @Override
        public void componentShown(ComponentEvent e) 
        {
            dbConnector = new DBHandler();
            dbConnector.makeConnection();

            ResultSet rs =  dbConnector.selectAllDetails("select client_id, Name from Client");

            DefaultTableModel model = (DefaultTableModel) ViewClientsTable.getModel();
            model.setRowCount(0);

            try {
                if(rs.isBeforeFirst()==false)
                {
                    JOptionPane.showMessageDialog(null,"The table is empty");
                }
                else
                {
                    try
                    {
                        while(rs.next())
                        {
                            int id = rs.getInt("client_id");
                            String name = rs.getString("Name");

                            ResultSet getPortfolios =  dbConnector.selectAllDetails("select portfolio_id from Portfolio where Client_Name = '"+name+"'");
                            JComboBox combo = new JComboBox();
                            combo.removeAllItems();

                            while(getPortfolios.next())
                            {
                                combo.addItem(getPortfolios.getString("portfolio_id"));
                            }

                            JButton update = new JButton("Update");
                            JButton delete = new JButton("Delete");

                            JPanel btnPanel = new JPanel();
                            btnPanel.setLayout(new FlowLayout());
                            btnPanel.add(update);
                            btnPanel.add(delete);


                            Object[]row = {id, name, 0, "", new ButtonColumn(ViewClientsTable,null,"delete",4)};

                            model.addRow(row);
                            ViewClientsTable.getColumn("Portfolio").setCellEditor(new DefaultCellEditor(combo));

                        }
                        dbConnector.closeConnection();
                    }
                    catch(SQLException sqlE)
                    {
                        sqlE.printStackTrace();
                        JOptionPane.showMessageDialog(null,sqlE.getLocalizedMessage());
                        dbConnector.closeConnection();
                    }
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
     }

dbConnector.selectAllDetails()方法

public ResultSet selectAllDetails(String query)
    {
        ResultSet r = null;
        try
        {
            Statement st = con.createStatement();

            r = st.executeQuery(query);
        }
        catch(SQLException sql)
        {
            sql.printStackTrace();
        }

        return r;
    }

这里的问题是我的JComboBox没有按预期填满。它应该根据提供的搜索查询填充数据，但它在所有行中显示相同的项目，即项目 03，它是客户名称 AAA .

下面是我的client表(带有虚拟输入)

下面是我的Portfolio表(带有虚拟输入)

为什么会发生这种情况？为什么JComboBox不是显示相关数据，而是重复相同的数据？

PS:我知道我们不应该根据 name 进行搜索但我们应该从“唯一 id”进行搜索，但这是对 SO 帖子的快速编辑。

Answer 1

首先将数据与其 View 分开，模型数据不应包含任何类型的 UI 组件或 UI 相关信息。做出这些决定不是模型的责任。模型携带数据，仅此而已。

表格中的单个单元格仅包含单个值，无论其设置为何。它只携带一个状态或值。

如何在屏幕上表示值是渲染器的领域，如何修改值是编辑器的领域。

构建您的 TableModel 并用数据填充它，将其传递给 JTable，它已配置了所需的渲染器和编辑器来显示和编辑您的数据。 .

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumnModel;

public class TableComboBox {

    public static void main(String[] args) {
        new TableComboBox();
    }

    public TableComboBox() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                DefaultTableModel model = new DefaultTableModel(new Object[]{"A", "B", "C", "D"}, 5);
                JTable table = new JTable(model);

                JComboBox bCombo = new JComboBox(new Object[]{"Apples", "Bannans", "Pears", "Grapes"});
                JComboBox cCombo = new JComboBox(new Object[]{"Elephants", "Monkeys", "Cats", "Dogs"});
                JComboBox dCombo = new JComboBox(new Object[]{"Unicorns", "Dragons", "Pixis", "Blobs"});

                DefaultCellEditor bEditor = new DefaultCellEditor(bCombo);
                DefaultCellEditor cEditor = new DefaultCellEditor(cCombo);
                DefaultCellEditor dEditor = new DefaultCellEditor(dCombo);

                TableColumnModel cm = table.getColumnModel();
                cm.getColumn(1).setCellEditor(bEditor);
                cm.getColumn(2).setCellEditor(cEditor);
                cm.getColumn(3).setCellEditor(dEditor);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }
}

看看How to Use Tables , Using Other Editors ，和Concepts: Editors and Renderers了解更多详情