Re: How can a JFrame be aware of keys pressed within controls?

From:

"Leonardo Azpurua" <leonardo@exmvps.org>

Newsgroups:

comp.lang.java.help

Date:

Fri, 19 Feb 2010 11:34:03 -0430

Message-ID:

<hlmcn8$jrg$1@news.eternal-september.org>

"John B. Matthews" <nospam@nospam.invalid> escribi? en el mensaje
news:nospam-2CDD93.17493017022010@news.aioe.org...

IIUC, the snippet in the "Focus Subsystem" article above uses the
Container's setFocusTraversalKeys() method to add a new KeyStroke;
no new listener is required:

Just for the record, it worked with this:

import java.util.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

class ToggleEnter {
  public static void activate(Container c) {
     Set forwardKeys =
c.getFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
     Set newForwardKeys = new HashSet(forwardKeys);
     newForwardKeys.add(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0));
     c.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
newForwardKeys);
  }

  public static void deactivate(Container c) {
     Set forwardKeys =
c.getFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
     Set newForwardKeys = new HashSet(forwardKeys);
     try {
       newForwardKeys.remove(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0));
       c.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
newForwardKeys);
     }
     catch (Exception ex) {
       System.err.println("Exception en ToggleEnter.deactivate: " +
ex.getMessage());
     }
  }
}

I activate VK_ENTER from the constructor, deactivate it on entry to any
control that requires it (like multiline text editors) and activate it back
on focusLost for those controls.

I haven't any real app written in Java yet, so I guess I have time to
develop a set of descedants of the basic controls in order to add whatever
additional functionality I might require.

Thanks, again.