JComboBox as a Custom TableCellEditor

Question

I have a table. Changes on that table update database. One column is edited by a JComboBox in that table. Clicks to any cell in that column fires a tableChanged event. Howev

Answer 1

I would highly recommend using SwingX which has a ComboBoxCellEditor component. It's essentially Sun's incubator for features Swing components should have. I have no idea if the project is still actively developed, but its mature, and I've used it in many projects.

If, for whatever reason, you can't or don't want to use an external library, here is their code (with parts modified to remove custom SwingX features), comments intact:

Note: the library is GPL'ed code.

/*
 * $Id: ComboBoxCellEditor.java 3738 2010-07-27 13:56:28Z bierhance $
 * 
 * Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, California 95054, U.S.A. All rights reserved.
 * 
 * This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;
import java.util.EventObject;

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;

/**
 * <p>
 * This is a cell editor that can be used when a combo box (that has been set up for automatic completion) is to be used in a JTable. The
 * {@link javax.swing.DefaultCellEditor DefaultCellEditor} won't work in this case, because each time an item gets selected it stops cell
 * editing and hides the combo box.
 * </p>
 * <p>
 * Usage example:
 * </p>
 * <p>
 * 
     * <pre>
 * <code>
 * JTable table = ...;
 * JComboBox comboBox = ...;
 * ...
 * TableColumn column = table.getColumnModel().getColumn(0);
 * column.setCellEditor(new ComboBoxCellEditor(comboBox));
 * </code>
 * </pre>
 * 
 * </p>
 */
public class ComboBoxCellEditor extends DefaultCellEditor {

    /**
     * Creates a new ComboBoxCellEditor.
     * 
     * @param comboBox the comboBox that should be used as the cell editor.
     */
    public ComboBoxCellEditor(final JComboBox comboBox) {
        super(comboBox);

        comboBox.removeActionListener(this.delegate);

        this.delegate = new EditorDelegate() {
            @Override
            public void setValue(final Object value) {
                comboBox.setSelectedItem(value);
            }

            @Override
            public Object getCellEditorValue() {
                return comboBox.getSelectedItem();
            }

            @Override
            public boolean shouldSelectCell(final EventObject anEvent) {
                if (anEvent instanceof MouseEvent) {
                    final MouseEvent e = (MouseEvent) anEvent;
                    return e.getID() != MouseEvent.MOUSE_DRAGGED;
                }
                return true;
            }

            @Override
            public boolean stopCellEditing() {
                if (comboBox.isEditable()) {
                    // Commit edited value.
                    comboBox.actionPerformed(new ActionEvent(ComboBoxCellEditor.this, 0, ""));
                }
                return super.stopCellEditing();
            }

            @Override
            public void actionPerformed(final ActionEvent e) {
                ComboBoxCellEditor.this.stopCellEditing();
            }
        };
        comboBox.addActionListener(this.delegate);
    }
}

Answer 2

Now it works. JComboBox needs to be reinitialized every time getTableCellEditorComponent method invoked. And in the itemstatechange of this JComboBox stopCellEditing() method must notify listeners that editing done when item is selected. That make the TableModelListener fireTableChanged event. (Fixed) However it also fires that event when you click a JComboBox after clicking another JComboBox without making a selection. (/Fixed)

Edit: Following code is the last version. By this TableModelListener is notified only when an item is selected. The problem mentioned above is fixed. It was because of default stopCellEditing() method always returned true. This cause cell editing stop in an unexpected way. It must be overriden as needed and fireEditingStopped(); must be used to notify TableModelListener

public class JIDCellEditor extends AbstractCellEditor implements TableCellEditor {

    private JComboBox jComboBox = new JComboBox();
    boolean cellEditingStopped = false;

    @Override
    public Object getCellEditorValue() {
        return jComboBox.getSelectedItem();
    }

    @Override
    public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
        Vector vector = new Vector();
        ArrayList<Integer> arrayList = new ArrayList<Integer>();
        arrayList.add(Integer.parseInt(value.toString()));
        vector.add(0);
        for (int i = 0; i < table.getRowCount(); i++) {
            if (!vector.contains(table.getValueAt(i, 0)) && table.getValueAt(i, 3).toString().equals("Sheep")) {
                vector.add(table.getValueAt(i, 0));
            }
        }
        vector.remove(table.getValueAt(row, 0));

        for (int i = 0; i < vector.size(); i++) {
        }
        jComboBox = new JComboBox(vector);
        jComboBox.setSelectedItem(value);

        jComboBox.addItemListener(new ItemListener() {

            @Override
            public void itemStateChanged(ItemEvent e) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    fireEditingStopped();
                }
            }
        });
        jComboBox.addPopupMenuListener(new PopupMenuListener() {

            @Override
            public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
                cellEditingStopped = false;
            }

            @Override
            public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
                cellEditingStopped = true;
                fireEditingCanceled();
            }

            @Override
            public void popupMenuCanceled(PopupMenuEvent e) {

            }
        });
        return jComboBox;
    }

    @Override
    public boolean stopCellEditing() {
        return cellEditingStopped;
    }
}