Re: why can't run!

"Andrew Thompson" <>
1 Dec 2006 20:19:10 -0800
hua song wrote:

i just learn java
write a applet..

That is a bad combination. Applets are not for beginners.
They are hard to debug, and hard to deploy (get to user).

but it can't show what i want...

What do you want?

can anyone help me?

Try this code instead, look carefully at the comments
as well..

import java.awt.*;
import java.awt.event.*; // required for compiling
import javax.swing.*;
import java.awt.Event.*;

/** Class names should be meaningful, and
'DrawApplet' means nothing to me. */
public class DrawApplet extends JApplet{

  public static int a;
  public static int b;

  public void init() {
    Container cp=getContentPane();
    ButtonListener bl=new ButtonListener();
    // this is an applet, it does not require 'show'.

/** The common way to write java class names is
EachWordUpperCase - for methods and attributes
it should usually be firstWordLowerCase() ...

This class/method used the reverse of that convention.
Very confusing. */
class ButtonListener
  extends JPanel
  implements ActionListener {

  public ButtonListener() {//????
    setLayout(new GridLayout(0,1));
    Button b1=new Button("rect");
    Button b2=new Button("oval");
    Button b3=new Button("round");

  public void actionPerformed(ActionEvent e) {

    String s=((Button)e.getSource()).getLabel() ;
      RectanglePanel p = new
    else if(s.equals("oval"))
      OvalPanel p = new
        OvalPanel(DrawApplet.a,DrawApplet.b );
    else if(s.equals("round"))
      RoundPanel p = new
        RoundPanel(DrawApplet.a,DrawApplet.b );

class RectanglePanel extends JPanel{

  private int aa;
  private int bb;

  public RectanglePanel(int a, int b) {

  public void paintComponent(Graphics g)
    g.drawRect( aa,bb,50,50);

class OvalPanel extends JPanel {

  private int aa;
  private int bb;

  OvalPanel(int aa,int bb) {

  // spelling is important!
  //public void paintComponment(Graphics g)
  public void paintComponent(Graphics g) {

class RoundPanel extends JPanel{

  private int aa;
  private int bb;

  public RoundPanel(int a, int b) {

  public void paintComponent(Graphics g) {
    g.drawOval( aa,bb,20,10);

<the HTML...>

<title>DrawApplet - Test</title>
  <param name='Value1' value='10'>
  <param name='Value2' value='10'>


</the HTML...>

This shows on screen, but I rewlised once I saw it,
that I have no idea what you are trying to do..

In any case, an electrical strom is on the way and
that regularly kills my power (and PC) as I better post
this and shut-down without too many more comments..


Andrew T.

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