InputMap/ActionMap key bindings for arrow keys, alt key

Question

I'm having trouble defining InputMap/ActionMap key bindings for the arrow keys and the Alt key. My bound actions never run. I believe the problem is that the arrows are used in focus navigation, and the Alt key is used for opening the menu. How can I get these key bindings to work? Is there any other way that I can get events from these keys? I'd even be happy with simple AWT KeyListener events at this point. Thanks.

Answer 1

I've been having this same problem. I built a demo application that demonstrates the problem. It all works fine until I add the JTree. The JTree seems to be consuming the arrow key strokes. Here is the code:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.KeyStroke;
public class ArrowKeyDemo extends JFrame implements ActionListener {
    private javax.swing.JTree tree;
    private javax.swing.JPanel panel;
    public ArrowKeyDemo() {
        initComponents();
        panel.registerKeyboardAction(this, "A",
                KeyStroke.getKeyStroke(KeyEvent.VK_A, 0, false),
                JComponent.WHEN_IN_FOCUSED_WINDOW);
        panel.registerKeyboardAction(this, "left",
                KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0, false),
                JComponent.WHEN_IN_FOCUSED_WINDOW);
    private void initComponents() {
        panel = new javax.swing.JPanel();
        tree = new javax.swing.JTree();
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
        panel.add(tree);
        getContentPane().add(panel, java.awt.BorderLayout.CENTER);
        pack();
    private void exitForm(java.awt.event.WindowEvent evt) {
        System.exit(0);
    public static void main(String args[]) {
        new ArrowKeyDemo().show();
    public void actionPerformed(ActionEvent actionEvent) {
        System.out.println(actionEvent);
}Having the JTree in there kills the ability to trap key strokes for any other purpose. This seems to be true of other Swing components as well. You can stop the JTree from consuming key strokes by adding the line:
tree.setActionMap(null);
But you will probably need to set the ActionMap to null for every Swing component that is trapping key strokes. I'm not 100% sure, but I think that includes scroll panes as well.
I'd love to hear a more elegant solution.
--Timothy Rogers