Problems with getting size of components...

Question

I have a JApplet. After setting up the GUI in the init() method I call getWidth() and getHeight() methods (also in the init() method) of a JPanel I have placed in the contentPane of that applet. Problem is that I get different values of the height and width in the init() method than when I do the same calls on the same panel inside the actionPerformed (for a JButton). What is up with this?
Here is basically what the code looks like (leaving out some details):
public class Blah extends JApplet implements actionListener {
JPanel panel;
public void init() {
Container contentPane = getContentPane();
contentPane.setLayout(new BorderLayout());
panel = new JPanel();
contentPane.add(panel, "Center");
JButton button = new JButton("Click me!", "South");
button.addActionListener(this);
contentPane.add(button);
//tried putting a repaint() here...doesn't help.
System.out.println(panel.getWidth() + ", " + panel.getHeight()) // (1)
public void actionPerformed(ActionEvent e) {
System.out.println(panel.getWidth() + ", " + panel.getHeight()) // different height than what I got in (1)!!!
Now, I guess I am doing something where it shouldn't be done - that Java hasn't determined exactly yet how the GUI is going to be laid out yet so some times I get differnt values from the two println's. This is driving me nuts. Could someone tell me what's the right thing to do here? Thanks in advance!

Answer 1

Yeah, I got it to work by moving the getWidth(), getHeight calls out of init() (where my gui was being set up) and into start().
"Every part of an GUI you are creating in a method will be validated at the moment the method is left. So you can not obtain the correct values for heigth and width inside the the creational-method."
Is this specific to the Applet's init() method or also true for applications? If not then what mechanism can we use in the case of applications to ensure that the GUI has been validated before we start trying to do getWidth(), getHeight(), etc, on them?
Thanks for you help.