在JTable中的单个单元格中更新JComboBox

Question

我需要根据在同一表中执行的操作，用组件（JComboBox）填充JTable中的特定单元格。

我已经设置了JTable。 A列中的所有单元格都填充有JComboBox。

我想为此修改我的代码（可以在下面找到），以便当用户在特定行的JComboBox中选择一个选项时，同一行（在B列中）的下一个字段将填充新的JComboBox中包含不同的项目。

这里的问题是我不想使用相同的JComboBox填充整个B列。 根据在A列中所做的选择，表中的每一行在B列的JComboBox中可以有不同的选项。

如何更改我的代码来做到这一点？

String sql = "SELECT * from tblDepartment ORDER BY deptName";
    int size = 0;
    int count = 0;
    try {
        pst = conn.prepareStatement(sql);
        rs = pst.executeQuery();
        List<String> list = new ArrayList<>();
        while (rs.next()) {//adds each item to the list for the combo box
            list.add(rs.getString("deptName"));
        }
        count = list.size();
        String[] items = list.toArray(new String[list.size()]);
        JComboBox<String> jcb = new JComboBox<>(items);
        TableColumn tc = tblCon.getColumnModel().getColumn(2);
        TableCellEditor tce = new DefaultCellEditor(jcb);//adds the combo box to the relevant cell in the table.
        tc.setCellEditor(tce);
    } catch (SQLException e) {
        JOptionPane.showMessageDialog(null, e);
    }

Answer 1

您可以重写JTable的getCellEditor(...)方法以返回特定的编辑器。

import java.awt.*;
import java.util.List;
import java.util.ArrayList;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.table.*;

public class TableComboBoxByRow extends JPanel
{
    List<String[]> editorData = new ArrayList<String[]>(3);

    public TableComboBoxByRow()
    {
        setLayout( new BorderLayout() );

        // Create the editorData to be used for each row

        editorData.add( new String[]{ "Red", "Blue", "Green" } );
        editorData.add( new String[]{ "Circle", "Square", "Triangle" } );
        editorData.add( new String[]{ "Apple", "Orange", "Banana" } );

        //  Create the table with default data

        Object[][] data =
        {
            {"Color", "Red"},
            {"Shape", "Square"},
            {"Fruit", "Banana"},
            {"Plain", "Text"}
        };
        String[] columnNames = {"Type","Value"};

        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        JTable table = new JTable(model)
        {
            //  Determine editor to be used by row
            public TableCellEditor getCellEditor(int row, int column)
            {
                int modelColumn = convertColumnIndexToModel( column );

                if (modelColumn == 1 && row < 3)
                {
                    JComboBox<String> comboBox1 = new JComboBox<String>( editorData.get(row));
                    return new DefaultCellEditor( comboBox1 );
                }
                else
                    return super.getCellEditor(row, column);
            }
        };

        JScrollPane scrollPane = new JScrollPane( table );
        add( scrollPane );
//      table.getColumnModel().getColumn(1).setCellRenderer(new ComboBoxRenderer2() );
    }
/*
    class ComboBoxRenderer2 extends DefaultTableCellRenderer
    {
        @Override
        public Component getTableCellRendererComponent(
            JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
        {
            JLabel label = (JLabel) super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            label.setIcon(UIManager.getIcon("Table.descendingSortIcon"));
            return label;
        }
    }
*/
    private static void createAndShowUI()
    {
        JFrame frame = new JFrame("Table Combo Box by Row");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( new TableComboBoxByRow() );
        frame.setSize(200, 200);
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}

在上面的示例中，编辑器仅由行确定。

在您的情况下，编辑器将由上一行中的行和数据确定。

Answer 2

您是否尝试过使用自定义TableCellEditor ？ 您可以使用称为getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column)的可重写方法getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column)在其中可以显式定义JComboBox应该出现的行和列。

这是JCheckBox的示例：

public class EditBoolean extends AbstractCellEditor implements TableCellEditor {

        private JCheckBox box;

        public EditBoolean() {
            // This is the component that will handle the editing of the cell value
            box = new JCheckBox();
        }

        // This method is called when editing is completed.
        // It must return the new value to be stored in the cell.
        @Override
        public Object getCellEditorValue() {
            return box.isSelected();
        }

        // This method is called when a cell value is edited by the user.
        @Override
        public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
            if(column == 2 && row == 4){

               if (value instanceof Boolean) {
                   box.setSelected((Boolean) (value));
               } else {
                   box.setSelected(Boolean.getBoolean((String) value));
               }
               return box;
            }
       }
}