Why doesn't key binding work in JDialog?

Question

I have a problem. My key binding Ctrl+Tab assigned to inputMap of JDialog doesn't work .

Please, copy-paste this code and type Ctrl+TAB to experience the problem. It should print to console but it doesn't.

public class PopupFilesAccessor extends JDialog {

    private static PopupFilesAccessor filesAccessor = new PopupFilesAccessor();

    private DefaultListModel<String> filesModel;
    private JList<String> files;

    public PopupFilesAccessor() {
        super(null, "Demo", ModalityType.APPLICATION_MODAL);
        super.setUndecorated(true);
        super.setAlwaysOnTop(true);
        super.setLocationRelativeTo(null);

        filesModel = new DefaultListModel<>();

        files = new JList<>(filesModel);
        files.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        files.setLayoutOrientation(JList.HORIZONTAL_WRAP);
        files.setVisibleRowCount(0);
        // files.setCellRenderer(new FilesListCellRenderer());

        InputMap inputMap = super.getRootPane().getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
        ActionMap actionMap = super.getRootPane().getActionMap();

        inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_TAB, InputEvent.CTRL_DOWN_MASK), "selectDown");
        actionMap.put("selectDown", new AbstractAction() {
            @Override
            public void actionPerformed(ActionEvent e) {
                selectNextItem();
            }

            private void selectNextItem() {
                System.out.println("Good! selectNextItem method is running");
            }
        });

        JScrollPane scrollBar = new JScrollPane(files);
        super.getContentPane().add(scrollBar);
    }

    private void prepareToShow() {
        List<String> openedFiles = Arrays.asList("item1", "item2", "item3", "item4", "item5", "item6", "item7");
        filesModel.clear();
        for (int i = 0; i < openedFiles.size(); i++) {
            String userFile = openedFiles.get(i);
            filesModel.addElement(userFile);
        }
        files.setSelectedIndex(1);
        super.pack();
    }

    public static void popup() {
        filesAccessor.prepareToShow();
        filesAccessor.setVisible(true);
        filesAccessor.requestFocusInWindow();
    }

    public static void main(String[] args) {
        PopupFilesAccessor.popup();
    }
}

Thanks!

Answer 1

It's not a good way but still you can try it using ActionEvent#paramString() if it suits you.

long eventMask = AWTEvent.KEY_EVENT_MASK;

Toolkit.getDefaultToolkit().addAWTEventListener(new AWTEventListener() {
    public void eventDispatched(AWTEvent e) {
        String paramString = e.paramString();
        // System.out.println(paramString);
        if (paramString.contains("KEY_RELEASED,keyCode=9,keyText=Tab,keyChar=Tab,modifiers=Ctrl,extModifiers=Ctrl")) {
            System.out.println("Ctrl+Tab keys are released");
        }
    }
}, eventMask);

Note: you can check other combination of param string also.