Editing JComboBox with keyboard

Question

One of my JTable columns has JComboBox. When I select the entries with the mouse it works fine. But when I use the keyboard and select the entries it is not getting updated in the display. Can somebody provide me pointers to fix this problem.
Thanks
Mahesh

Answer 1

See here the complete class.
just check for the combo_keyPressed method. There will be some other methods you will need in order to make it work.
Check it out and see what you need.
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Vector;
import javax.swing.ComboBoxModel;
import javax.swing.JComboBox;
* <p>Title: KComboBox Class</p>
* <p>Description: This class provides the functionality for selecting the closest value
* in the combobox compared to the keystrokes which are made. There are two additional
* parameters added to this class which provides the option of the casesensitivity comparision
* between the element in the list and the keystrokes made. Also the interval for reseting
* the keystroke string is an additional parameter. These can be set through the 2 methods
* setCasesensitivity and the setStrokeInterval. If those two parameters are not set
* by the user. The default values will be use in that case.</p>
* @author Stefaan Delanghe
* @version 1.0
public class KComboBox extends JComboBox
* the default value for the keystroke interval
private final static long const_DEFAULT_STROKEINTERVAL = 900;
* the default value for the casesentive option
private final static boolean const_DEFAULT_CASESENITIVE = false;
* holds the time which may not be bypassed to reset the current keystrokes
private long m_strokeinterval = const_DEFAULT_STROKEINTERVAL;
* holds if the comparison of the keystrokes must be case sensitive or not
private boolean m_casensitive = const_DEFAULT_CASESENITIVE;
* holds the time of the first keystroke initiated
private long m_beginkeypress = System.currentTimeMillis();
* holds the time when the next key was pressed
private long m_nextkeypress;
* holds the current pressed key
private char m_keychar;
* holds the keystrokes pressed within the interval
private String m_keystring;
* default constructor with addition of adding the listener for the keystrokes.
public KComboBox() { super(); setListeners(); }
* constructor with setting a combobox model and adding the listener for the keystrokes.
* @param _model ComboBoxModel The model definition for the combobox
public KComboBox(ComboBoxModel _model) { super(_model); setListeners(); }
* constructor with setting of the elements as an object array and as addition the listener
* for the keystrokes.
* @param _items Object[] List of the elements which should be included in the combobox
public KComboBox(Object[] _items) { super(_items); setListeners(); }
* constructor with setting of the elements as a vector and as addition the listener
* for the keystrokes.
* @param _items Vector List of the elements which should be included in the combobox
public KComboBox(Vector _items) { super(_items); setListeners(); }
* sets the listeners needed for the implementation of the keystroke. This method
* only defines the keypressed method for handling the keystrokes.
private void setListeners()
addKeyListener(new KeyAdapter()
public void keyPressed(KeyEvent e)
combo_keyPressed(e);
* method for interpretation of the keystrokes and select the closest element in the combobox.
* @param e KeyEvent object holding the values and method in association with the keystroke
private void combo_keyPressed(KeyEvent e)
boolean reset = false;
boolean found = false;
String listvalue = "";
m_nextkeypress = System.currentTimeMillis();
if(m_nextkeypress - m_beginkeypress > m_strokeinterval)
reset = true;
if(reset)
m_keychar = e.getKeyChar();
m_keystring = String.valueOf(m_keychar);
m_beginkeypress = System.currentTimeMillis();
m_nextkeypress = m_beginkeypress;
else
m_keystring += e.getKeyChar();
m_nextkeypress = System.currentTimeMillis();
int cntlist = 0;
for(cntlist = 0; cntlist < getItemCount() && !found; cntlist++)
listvalue = getItemAt(cntlist).toString();
if(m_keystring.length() > listvalue.length())
found = true;
else
if(listvalue.length() >= m_keystring.length())
if(m_casensitive)
if(listvalue.substring(0,m_keystring.length()).compareTo(m_keystring) >= 0)
found = true;
else
if(listvalue.substring(0,m_keystring.length()).compareToIgnoreCase(m_keystring) >= 0)
found = true;
cntlist--;
if(found)
setSelectedIndex(cntlist);
* sets the interval between keystrokes that are concatenated for comparison to the
* element in the combobox. Each time that interval has been passed the keystroke string
* will be reset.<br>
* A default value is specified to 900.
* @param _interval long The new interval value
public void setStrokeInterval(long _interval)
m_strokeinterval = _interval;
* set the if the comparison of the keystrokes should be case sensitive or not. A default
* value is specified with a contact which is false.
* @param _set boolean use true in case you want to set the casesentivity otherwise use false
public void setCasensitive(boolean _set)
m_casensitive = _set;
}