Why doesn't my JDialog content paint?

Question

Folks,
I started playing with converting the "little mouse-maze" game in [this thread|http://forums.sun.com/thread.jspa?threadID=5353283] from an applet to a swing app, and I'm stuck.
The contents of the "Game Over" JDialog doesn't paint (I see dialog border, but the background through content window... and I'm totally clueless as to why or what to do about it... It's pretty obvious that it's a side-effect of the custom painting routine... which I presume must be painting over the top of the dialog content... or maybe the dialog isn't being painted at all because I've blocked the parent's paint-component by showing the dialogue... Hmmm, maybe I need to invoke-it-Later?
package forums;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import javax.swing.*;
public class MaxWallacesCollision extends JPanel
  private static final long serialVersionUID = 1L;
  private static final int[] leftWallX = {0,204,204,149,149,162,162,243,260,235,259,232,260,230,207,207,0};
  private static final int[] leftWallY = {500,499,402,402,341,324,227,191,157,141,135,123,116,109,86,1,1};
  private static final int[] playAreaX = {204,204,149,149,162,162,243,260,235,259,232,260,230,207,207,263,263,245,282,262,274,257,273,250,184,184,170,170,208,216,216};
  private static final int[] playAreaY = {499,402,402,341,324,227,191,157,141,135,123,116,109,86,1,1,86,103,115,129,138,147,155,201,230,323,340,384,384,402,499};
  private static final int[] rightWallX = {500,500,263,263,245,282,262,274,257,273,250,184,184,170,170,208,216,216};
  private static final int[] rightWallY = {500,0,1,86,103,115,129,138,147,155,201,230,323,340,384,384,402,499};
  private static final int START_X = 208;
  private static final int START_Y = 490;
  private Polygon leftWall = new Polygon(leftWallX, leftWallY, 17);
  private Polygon playerArea = new Polygon(playAreaX, playAreaY, 31);
  private Polygon rightWall = new Polygon(rightWallX, rightWallY, 18);
  private Rectangle rect = new Rectangle(3,3);
  private Rectangle goal = new Rectangle(207,0,55,25);
  private JFrame frame;
  private boolean listening = false;
  private boolean mouseInside = false;
  public MaxWallacesCollision() {
    super( (LayoutManager)null );
    this.addMouseListener(new MouseAdapter() {
      @Override
      public void mouseEntered(MouseEvent e) {
        //System.out.println("DEBUG: mouseEntered");
        mouseInside=true;
      @Override
      public void mouseExited(MouseEvent e) {
        //System.out.println("DEBUG: mouseExited");
        mouseInside=false;
    this.addMouseMotionListener(new MouseMotionListener() {
      @Override
      public void mouseMoved(MouseEvent e) {
        //System.out.println("DEBUG: mouseMoved"+e.getX()+" "+e.getY());
        //move the yellow square according to mouse position
        rect.setLocation(e.getX()-rect.width/2, e.getY()-rect.height/2);
        repaint();
      public void mouseDragged(MouseEvent e) {
    final JButton startButton = new JButton("Start");
    startButton.setBounds(START_X-25, START_Y-14, 50, 25);
    startButton.setMargin(new Insets(1,1,1,1)); // top, left, bottom, right
    startButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        listening=true;
        startButton.setVisible(false);
    super.add(startButton);
  public Dimension getPreferredSize() {
    return new Dimension(500,500);
  public void paintComponent(Graphics g2d) {
    super.paintComponent(g2d);
    g2d.setColor(Color.WHITE);
    g2d.fillRect(0,0, (int)getSize().getWidth(), (int)getSize().getHeight() );
    g2d.setColor(Color.BLUE);
    g2d.fillPolygon(playerArea);
    g2d.setColor(Color.GREEN);
    g2d.fillRect(goal.x, goal.y, goal.width, goal.height);
    g2d.setColor(Color.RED);
    g2d.fillPolygon(leftWall);
    g2d.fillPolygon(rightWall);
    g2d.setColor(Color.YELLOW);
    g2d.setFont(new Font("Helvetica",Font.BOLD,16));
    if (mouseInside) {
      g2d.fillRect(rect.x, rect.y, rect.width, rect.height);
    } else {
      g2d.fillRect(START_X, START_Y, rect.width, rect.height);
    g2d.setColor(Color.BLACK);
    if (listening && mouseInside && (leftWall.intersects(rect)||rightWall.intersects(rect)) ) {
      listening = false;
      g2d.drawString("Crashed!", rect.x, rect.y);
      for ( MouseMotionListener l : getMouseMotionListeners() ) {
        removeMouseMotionListener(l);
      JOptionPane.showMessageDialog(SwingUtilities.getWindowAncestor(this), "Collision!", "Game Over", JOptionPane.INFORMATION_MESSAGE);
      System.exit(1);
  public static void main (String[] args) throws Exception {
    SwingUtilities.invokeLater(
      new Runnable() {
        public void run() {
          JFrame frame = new JFrame("Add Text to List");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.setContentPane(new MaxWallacesCollision());
          frame.pack();
          frame.setVisible(true);
}Any guidance would be appreciated.
Thanx all. Keith.

Answer 1

I tried the invokeLater thingummy... which seems to work... Still, What's going on here? I guess the modal-dialog blocked the EDT, so no part of the app could be repainted? Is that it?
package forums;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import javax.swing.*;
public class MaxWallacesCollision extends JPanel
  private static final long serialVersionUID = 1L;
  private static final int[] leftWallX = {0,204,204,149,149,162,162,243,260,235,259,232,260,230,207,207,0};
  private static final int[] leftWallY = {500,499,402,402,341,324,227,191,157,141,135,123,116,109,86,1,1};
  private static final int[] playAreaX = {204,204,149,149,162,162,243,260,235,259,232,260,230,207,207,263,263,245,282,262,274,257,273,250,184,184,170,170,208,216,216};
  private static final int[] playAreaY = {499,402,402,341,324,227,191,157,141,135,123,116,109,86,1,1,86,103,115,129,138,147,155,201,230,323,340,384,384,402,499};
  private static final int[] rightWallX = {500,500,263,263,245,282,262,274,257,273,250,184,184,170,170,208,216,216};
  private static final int[] rightWallY = {500,0,1,86,103,115,129,138,147,155,201,230,323,340,384,384,402,499};
  private static final int START_X = 208;
  private static final int START_Y = 490;
  private Polygon leftWall = new Polygon(leftWallX, leftWallY, 17);
  private Polygon playerArea = new Polygon(playAreaX, playAreaY, 31);
  private Polygon rightWall = new Polygon(rightWallX, rightWallY, 18);
  private Rectangle rect = new Rectangle(3,3);
  private Rectangle goal = new Rectangle(207,0,55,25);
  private JFrame frame;
  private boolean listening = false;
  public MaxWallacesCollision() {
    super( (LayoutManager)null );
    this.addMouseListener(new MouseAdapter() {
      @Override
      public void mouseExited(MouseEvent e) {
        listening=false;
    this.addMouseMotionListener(new MouseMotionListener() {
      @Override
      public void mouseMoved(MouseEvent e) {
        //move the yellow square according to mouse position
        rect.setLocation(e.getX()-rect.width/2, e.getY()-rect.height/2);
        repaint();
      public void mouseDragged(MouseEvent e) {
    final JButton startButton = new JButton("Start");
    startButton.setBounds(START_X-25, START_Y-14, 50, 25);
    startButton.setMargin(new Insets(1,1,1,1)); // top, left, bottom, right
    startButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        listening=true;
        startButton.setVisible(false);
    super.add(startButton);
  public Dimension getPreferredSize() {
    return new Dimension(500,500);
  public void paintComponent(Graphics g2d) {
    super.paintComponent(g2d);
    g2d.setColor(Color.WHITE);
    g2d.fillRect(0,0, (int)getSize().getWidth(), (int)getSize().getHeight() );
    g2d.setColor(Color.BLUE);
    g2d.fillPolygon(playerArea);
    g2d.setColor(Color.GREEN);
    g2d.fillRect(goal.x, goal.y, goal.width, goal.height);
    g2d.setColor(Color.RED);
    g2d.fillPolygon(leftWall);
    g2d.fillPolygon(rightWall);
    g2d.setColor(Color.YELLOW);
    g2d.setFont(new Font("Helvetica",Font.BOLD,16));
    if (listening) {
      g2d.fillRect(rect.x, rect.y, rect.width, rect.height);
    } else {
      g2d.fillRect(START_X, START_Y, rect.width, rect.height);
    g2d.setColor(Color.BLACK);
    if (listening && (leftWall.intersects(rect)||rightWall.intersects(rect)) ) {
      listening = false;
      g2d.drawString("Crashed!", rect.x, rect.y);
      SwingUtilities.invokeLater(new Runnable() {
        public void run() {
          crash();
  private void crash() {
    for ( MouseMotionListener l : getMouseMotionListeners() ) {
      removeMouseMotionListener(l);
    JOptionPane.showMessageDialog(SwingUtilities.getWindowAncestor(this), "You crashed!", "Game Over", JOptionPane.INFORMATION_MESSAGE);
    System.exit(1);
  public static void main (String[] args) throws Exception {
    SwingUtilities.invokeLater(
      new Runnable() {
        public void run() {
          JFrame frame = new JFrame("Add Text to List");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.setContentPane(new MaxWallacesCollision());
          frame.pack();
          frame.setVisible(true);
}The challend is to "move" the mouse-pointer automagically to the start position... sounds hard, coz I bet that ain't "normal"... Maybe Robot can do that?
Cheers all. Keith.