Redispatching MouseEvents Through GlassPane

Question

Hey all,
I'm trying to do some drawing on a GlassPane overtop of a JFrame consisting of several Components. I followed the tutorial on GlassPanes I found [here |http://java.sun.com/docs/books/tutorial/uiswing/components/rootpane.html#glasspane] to redispatch MouseEvents through the GlassPane to the proper Components underneath.
For the most part, this works perfectly. But there are several Components for which this doesn't seem to redispatch correctly (I used a JComboBox in the SSCCE, but I'm experiencing a similar problem with JTabbedPane as well). The problem arises when a Component contains "extra parts" that overlap another Component (like when the JComboBox's list extends on top of the JPanel.. Or, I'm assuming, when a JTabbedPane's tabs do the same).
Anyway, any insight into this would be much appreciated.
SSCCE:
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
public class GlassPaneTest{
     JFrame frame = new JFrame("Testing GlassPane");
     public GlassPaneTest(){     
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          BoxLayout layout = new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS);
          frame.getContentPane().setLayout(layout);
          JPanel buttonPanel = new JPanel();
          buttonPanel.add(new JButton("button"));
          buttonPanel.add(new JComboBox(new String[]{"one", "two", "three"}));
          frame.add(buttonPanel);
          createGlassPane();
          frame.setMinimumSize(new Dimension(200,200));
          frame.setMaximumSize(new Dimension(200,200));
          frame.setPreferredSize(new Dimension(200,200));
          frame.setVisible(true);
     public void createGlassPane(){
          final Point mousePoint = new Point(0,0);
          final JPanel glassPanel = new JPanel(){
               public void paintComponent(Graphics g){
                    super.paintComponent(g);
                    g.setColor(Color.GREEN);
                    g.fillOval((int)mousePoint.getX(), (int)mousePoint.getY(), 20, 20);
          MouseAdapter mouseAdapter = new MouseAdapter(){
               public void mouseClicked(MouseEvent me){
                    redispatchMouseEvent(me);
               public void mouseEntered(MouseEvent me){
                    redispatchMouseEvent(me);
               public void mouseExited(MouseEvent me){
                    redispatchMouseEvent(me);
               public void mousePressed(MouseEvent me){
                    redispatchMouseEvent(me);
               public void mouseReleased(MouseEvent me){
                    redispatchMouseEvent(me);
               public void mouseDragged(MouseEvent me){
                    redispatchMouseEvent(me);
               public void mouseMoved(MouseEvent me){
                    mousePoint.setLocation(me.getX(), me.getY());
                    glassPanel.repaint();
                    redispatchMouseEvent(me);
               public void mouseWheelMoved(MouseWheelEvent me){
                    redispatchMouseEvent(me);
               public void redispatchMouseEvent(MouseEvent me){
                    Point glassPanelPoint = me.getPoint();
                    Container container = frame.getContentPane();
                    Point containerPoint = SwingUtilities.convertPoint(glassPanel,
                                                  glassPanelPoint, container);
                    if(containerPoint.getY() >= 0){
                         Component component =
                              SwingUtilities.getDeepestComponentAt(container, (int)containerPoint.getX(), (int)containerPoint.getY());
                         if(component != null){
                              Point componentPoint = SwingUtilities.convertPoint(glassPanel, glassPanelPoint, component);
                              System.out.println("mouse " + component.getClass().toString());
                              component.dispatchEvent(new MouseEvent(component,
                                        me.getID(),
                                        me.getWhen(), me.getModifiers(),
                                        (int)componentPoint.getX(),
                                        (int)componentPoint.getY(),
                                        me.getClickCount(),
                                        me.isPopupTrigger()));
                         else{
                              System.out.println("null component");
          glassPanel.addMouseListener(mouseAdapter);
          glassPanel.addMouseMotionListener(mouseAdapter);
          glassPanel.setOpaque(false);
          frame.setGlassPane(glassPanel);
          glassPanel.setVisible(true);
     public static void main(String [] argS){
          new GlassPaneTest();
}

Answer 1

jboeing wrote:
It appears that the Motif LnF doesn't actually contain the mouse-over highlight at all, even without a glass pane.:o right you are! I had to laugh at myself when I read this. I guess I was looking for things that went wrong since adding the GlassPane and started picking up on things that didn't actually change. Wow. Who knows how long I would have pounded away at that "problem" if you hadn't pointed that out?
Otherwise, I did successfully get the lightweight solution to work:Thanks so much for taking the time to come up with and offer a solution. I also came across [this page|http://weblogs.java.net/blog/alexfromsun/archive/2006/09/a_wellbehaved_g.html] offering another solution (even to some problems that I didn't know about at first, interesting read).
Following that page, I came up with this approach:
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
public class GlassPaneTest{
     JFrame frame = new JFrame("Testing GlassPane");
     JComboBox comboBox = new JComboBox(new String[]{"one", "two", "three"});
     public GlassPaneTest(){
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          BoxLayout layout = new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS);
          frame.getContentPane().setLayout(layout);
          JPanel buttonPanel = new JPanel();
          buttonPanel.add(new JButton("button"));
          buttonPanel.add(comboBox);
          frame.add(buttonPanel);
          createGlassPane();
          frame.setMinimumSize(new Dimension(200,200));
          frame.setMaximumSize(new Dimension(200,200));
          frame.setPreferredSize(new Dimension(200,200));
          frame.setVisible(true);
     public void createGlassPane(){
          final Point mousePoint = new Point(0,0);
          final JPanel glassPanel = new JPanel(){
               public void paintComponent(Graphics g){
                    super.paintComponent(g);
                    g.setColor(Color.GREEN);
                    g.fillOval((int)mousePoint.getX(), (int)mousePoint.getY(), 20, 20);
               public boolean contains(int x, int y){
                    return false;
          AWTEventListener awtListener = new AWTEventListener(){
               public void eventDispatched(AWTEvent e){
                    if(e instanceof MouseEvent){
                         MouseEvent me = (MouseEvent)e;
                         MouseEvent converted = SwingUtilities.convertMouseEvent(me.getComponent(), me, glassPanel);
                         mousePoint.setLocation(converted.getX(), converted.getY());
                         glassPanel.repaint();
          Toolkit.getDefaultToolkit().addAWTEventListener(awtListener, AWTEvent.MOUSE_MOTION_EVENT_MASK | AWTEvent.MOUSE_EVENT_MASK);
          glassPanel.setOpaque(false);
          frame.setGlassPane(glassPanel);
          glassPanel.setVisible(true);
     public static void main(String [] argS){
                    try {
                         UIManager
                         .setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
                    } catch (Exception e) {
                         e.printStackTrace();
          new GlassPaneTest();
}Does anybody see anything glaringly wrong with this? It seems to work perfectly, so I'm calling it a week :)
Thanks again!