Registering keyboard listener

Question

Hi,
In my application I have a JFrame and I add panels to the frame. The JFrame has a menubar which contains menus and menuitems. My problem is that I want to catch keyboard events. After the frame comes up, I should be able to hit certain keys and perform certain actions which will modify the UI.
I tried adding a keyboard listener to the content pane of the frame but it didn't work. What I did was as follows:
getContentPane.addkeyListener( new KeyAdapter()
public void keyReleased (KeyEvent ke)
// do something
Can anybody help?
thanks a lot in advance,
-Amitabh

Answer 1

The events are probably being handled at a lower level (subcomponents) and never getting fired to the ContentPane.
I would suggest extending the DefaultKeyboardFocusManager class and overridding the processKeyEvent or dispatchKeyEvent method.
public class YourKeyboardFocusManager extends DefaultKeyboardFocusManager
    private   KeyboardFocusManager m_initialManager   = KeyboardFocusManager.getCurrentKeyboardFocusManager();
    public YourKeyboardFocusManager()
        super();
        KeyboardFocusManager.setCurrentKeyboardFocusManager(this);
    public boolean dispatchKeyEvent(KeyEvent event)
        Component component = event.getComponent();
        System.out.println("component dispatching the  KeyEvent : "+component.getClass().getName());
        switch (event.getKeyCode())
          case KeyEvent.VK_WHATEVER_KEY_YOU_WANT:
                 //DO YOUR STUFF HERE
                  event.consume();
                  break;
          default:
                return m_initialManager.dispatchKeyEvent(event);
         return m_initialManager.dispatchKeyEvent(event);
} Now this class will pick up every single key event posted to the AWTEventQueue before it is dispatched. This may be overkill but it does what you need. You can look into setting up your own keyevent dispatcher if you want and adding that to the current KeyboardFocusManager opposed to writing your own like above.
Anyway, should be enough here to fix your problem.
Hope this helps
nes