Help Painting in Swing

Question

I'm new to Swing, and am having trouble painting both buttons and other graphics.
For instance:
package example.src;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import example.src.*;
public class Example extends JFrame {
    public Example() {
         this.setSize(500, 500);
         this.setTitle("Example");
         addWindowListener(new WindowAdapter() {
              public void windowClosing(WindowEvent e)
                    System.exit(0);
          Container c = this.getContentPane();
          c.add(new DrawPanel());
          c.add(new ButtonPanel());
    public static void main(String[] args) {
         JFrame Drawing_Ex = new Example();
         Drawing_Ex.setVisible(true);
package example.src;
import java.awt.*;
import javax.swing.*;
public class DrawPanel extends JPanel implements Runnable
     private boolean x = true;
     public DrawPanel() {
          Thread thread = new Thread(this);
          thread.start();
     public void run() {
         int counter = 0;
         while (true) {
              counter++;
              if (counter == 500) {
                   if (x) {
                        x = false;
                   else {
                        x = true;
                   counter = 0;
              this.repaint();
              try {
                   Thread.sleep(1);
              catch (InterruptedException ex) {
                   System.out.println("Failed.");
    public void paintComponent(Graphics g) {
         super.paintComponent(g);
         g.setColor(Color.blue);
         if (x) {
              g.drawString("YES", 100, 100);
         else g.drawString("NO", 100, 100);
package example.src;
import javax.swing.JButton;
import javax.swing.JPanel;
import java.awt.event.*;
import java.awt.*;
public class ButtonPanel extends JPanel {
public static JButton play;
public static JButton changeCpu;
    public ButtonPanel() {
         super();
         this.setLayout(null);
         play = new JButton("Restart");
        play.setBounds(420, 170, 80, 30);
        play.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent event) {
        this.add(play);
        play.setVisible(true);
        changeCpu = new JButton("Change Level");
        changeCpu.setBounds(300, 170, 120, 30);
        changeCpu.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent event) {
        changeCpu.setVisible(true);
        this.add(changeCpu);
}This should have two buttons, as well as a string yes/no that switches. However, if the buttons get added last to the content pane, the string doesn't show, and if the drawing gets added last, the buttons won't show. Any help?
(This is for a pong game - I want two buttons, one that changes the Cpu's level and another that restarts the game, and I need the player, enemy, and ball to be drawn).

Answer 1

Both using and understanding layouts, is vital in the Java X-plat language. The sooner people realize that, the better off they are.
There were other things in the code that were either questionable or could be improved, but I stuck to concentrating of the layout.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Example extends JFrame {
  public Example() {
    this.setSize(500, 500);
    this.setTitle("Example");
    addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e)
        System.exit(0);
    Container c = this.getContentPane();
    // 'when EAST meets WEST' otherwise they are
    // stacked, and only one is visible!
    c.add(new DrawPanel(), BorderLayout.WEST);
    c.add(new ButtonPanel(), BorderLayout.EAST);
    // always (validate or) pack() the main UI
    // otherwise unpredictable behaviour will be seen
    pack();
  public static void main(String[] args) {
    JFrame Drawing_Ex = new Example();
    Drawing_Ex.setVisible(true);
class DrawPanel extends JPanel implements Runnable
  private boolean x = true;
  public DrawPanel() {
    Thread thread = new Thread(this);
    thread.start();
    // important, so the layout does not collapse the empty
    // panel to 0x0
    setPreferredSize( new Dimension(200,200) );
  public void run() {
    int counter = 0;
    while (true) {
      counter++;
      if (counter == 500) {
        if (x) {
          x = false;
        else {
          x = true;
        counter = 0;
      this.repaint();
      try {
        Thread.sleep(1);
      catch (InterruptedException ex) {
        System.out.println("Failed.");
  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    g.setColor(Color.blue);
    if (x) {
      g.drawString("YES", 100, 100);
    else g.drawString("NO", 100, 100);
class ButtonPanel extends JPanel {
  public static JButton play;
  public static JButton changeCpu;
  public ButtonPanel() {
    super();
    // don't do that, except in a layout manager..
    //this.setLayout(null);
    play = new JButton("Restart");
    // use a layout manager with appropriate padding,
    // or add borders to the components
    //play.setBounds(420, 170, 80, 30);
    play.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
    this.add(play);
    play.setVisible(true);
    changeCpu = new JButton("Change Level");
    changeCpu.setBounds(300, 170, 120, 30);
    changeCpu.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
    changeCpu.setVisible(true);
    this.add(changeCpu);
}Edited by: AndrewThompson64 on May 31, 2008 6:56 AM