Editable JComboBox in a JTable

Question

I posted my problem into the "Java Essentials/Java programming" forum but it would be much better if I'd posted it here into the swing theme :).
Here it is what I posted:
Funky_1321
Posts:8
Registered: 2/22/06
editable JComboBox in a JTable
Oct 21, 2006 1:32 PM
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Hello!
Yesterday I posted a problem, solved it and there's another one, referring the same theme.
So it's about a editable JComboBox with autocomplete function. The combo is a JTables cellEditors component. So it's in a table. So when the user presses the enter key to select an item from the JComboBox drop down menu, I can't get which item is it, not even which index has the item in the list. If for exemple the JComboBox isn't in a table but is added on a JPanel, it works fine. So I want to get the selectedItem in the actionPerformed method implemented in the combo box. I always get null instead of the item.
Oh... if user picks up some item in the JComboBox-s list with the mouse, it's working fine but I want that it could be picked up with the enter key.
Any solutions appreciated!
Thanks, Tilen
YAT_Archivist
Posts:1,321
Registered: 13/08/05
Re: editable JComboBox in a JTable
Oct 21, 2006 1:55 PM (reply 1 of 2)
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I suggest that you distill your current code into a simple class which has the following attributes:
1. It can be copied and pasted and will compile straight out.
2. It has a main method which brings up a simple example frame.
3. It's no more than 50 lines long.
4. It demonstrates accurately what you've currently got working.
Without that it's hard to know exactly what you're currently doing, and requires a significant investment of time for someone who hasn't already solved this problem before to attempt to help. I'm not saying that you won't get help if you don't post a simple demo class, but it will significantly improve your chances.
Funky_1321
Posts:8
Registered: 2/22/06
Re: editable JComboBox in a JTable
Oct 21, 2006 2:11 PM (reply 2 of 2)
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Okay ... I'll write the code in short format:
class acJComboBox extends JComboBox {
  public acJComboBox() {
    this.setEditable(true);
    this.setSelectedItem("");
    this.getEditor().getEditorComponent().addKeyListener(new KeyAdapter() { public void keyReleased(KeyEvent e) {
     // ... code code code
     // that's tricky ... the method getSelectedItem() always returns null - remember; the acJComboBox is in a JTable!
     if (e.getKeyCode() == 10 && new String((String)getEditor().getItem()).length() != 0) { getEditor().setItem(getSelectedItem()); }
}And something more ... adding the acJComboBox into the JTable:
TableColumn column = someTable.getColumn(0);
column.setCellEditor(new DefaultCellEditor(new acJComboBox());
So if the user presses the enter key to pick up an item in the combo box drop down menu, it should set the editors item to the selected item from the drop down menu (
getEditor().setItem(getSelectedItem());
When the acJComboBox is on a usual JPanel, it does fine, but if it's in the JTable, it doesn't (getSelectedItem() always returns null).
Hope I described the problem well now ;).

Answer 1

Okay look ... I couldn't write a shorter code just for an example. I thought that my problem could be understoodable just in mind. However ... type in the first combo box the letter "i" and then select some item from the list with pressing the enter key. Do the same in the 2nd combo box who's in the JTable ... the user just can't select that way if the same combo is in the JTable. Why? Thanks alot for future help!
the code:
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Vector;
import javax.swing.DefaultCellEditor;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;
class Example extends JFrame {
    private String[] columns = { "1", "2", "3" };
    private String[][] rows = {};
    private DefaultTableModel model = new DefaultTableModel(rows, columns);
    private JTable table = new JTable(model);
    private JScrollPane jsp = new JScrollPane(table);
    private acJComboBox jcb1 = new acJComboBox();
    private acJComboBox jcb2 = new acJComboBox();
    public Example() {
        // initialize JFrame
        this.setLayout(null);
        this.setLocation(150, 30);
        this.setSize(300, 300);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        // initialize JFrame
        // initialize components
        Vector<String> v1 = new Vector<String>();
        v1.add("item1");
        v1.add("item2");
        v1.add("item3");
        jcb1.setData(v1);
        jcb2.setData(v1);
        jcb1.setBounds(30, 30, 120, 20);
        jsp.setBounds(30, 70, 250, 100);
        add(jcb1);
        add(jsp);
        TableColumn column = table.getColumnModel().getColumn(0);
        column.setCellEditor(new DefaultCellEditor(jcb2));
        Object[] data = { "", "", "" };
        model.addRow(data);
        // initialize components
        this.setVisible(true);
    public static void main(String[] args) {
        Example comboIssue = new Example();
class acJComboBox extends JComboBox {
    private Vector<String> data = new Vector<String>();
    private void init() {
        this.setEditable(true);
        this.setSelectedItem("");
        this.setData(this.data);
        this.getEditor().getEditorComponent().addKeyListener(new KeyAdapter() { public void keyReleased(KeyEvent e) {
                    if (e.getKeyCode() != 38 && e.getKeyCode() != 40) {
                        String a = getEditor().getItem().toString();
                        setModel(new DefaultComboBoxModel());
                        int st = 0;
                        for (int i = 0; i < getData().size(); i++) {
                            String str1 = a.toUpperCase();
                            String tmp = (String)getData().get(i).toUpperCase();
                            if (str1.length() <= tmp.length()) {
                                String str2 = tmp.substring(0, str1.length());
                                if (str1.equals(str2)) {
                                    DefaultComboBoxModel model = (DefaultComboBoxModel)getModel();
                                    model.insertElementAt(getData().get(i), getItemCount());
                                    st++;
                        getEditor().setItem(new String(a));
                        JTextField jtf = (JTextField)e.getSource();
                        jtf.setCaretPosition(jtf.getDocument().getLength());
                        hidePopup();
                        if (st != 0 && e.getKeyCode() != 10 && new String((String)getEditor().getItem()).length() != 0) { showPopup(); }
                        if (e.getKeyCode() == 10 && new String((String)getEditor().getItem()).length() != 0) { getSelectedItem(); }
                        if (new String((String)getEditor().getItem()).length() == 0) { whenEmpty(); }
        this.addMouseListener(new MouseAdapter() { public void mouseReleased(MouseEvent e) {
            hidePopup();
    // - constructors -
    public acJComboBox() {
        init();
    public acJComboBox(Vector<String> data) {
        this.data = data;
        init();
    // - constructors -
    // - interface -
    public void whenEmpty() { } // implement if needed
    public void setData(Vector<String> data) {
        this.data = data;
        for (int i = 0; i < data.size(); i++) {
            this.addItem(data.get(i));
    public Vector<String> getData() {
        return this.data;
    // - interface -
}