Thread: Components I add to JApplet won't appear!

For the life of me, I can't figure out what's wrong.

I want my Applet to have two Panels. One in BorderLayout.Center, and another in South.

Right now, all I'm trying to do is get one of the two panels to appear. It has a paint method which should draw a border, but nothing happens. In fact, the main content pane doesn't even show it's background color!

Perhaps there's something wrong with the DisplayPanel class I define at the end? It's just supposed to be a JPanel, basically, but I needed to be able to paint on it. So, I defined a the DisplayPanel class.

 
import java.awt.*;
import javax.swing.*;
 
public class ShooterApplet extends JApplet {
 
	private int height, width;
	Container mainContentPane;
		DisplayPanel displayPanel; 
		JPanel controlPanel;
 
	public void init() {
 
		mainContentPane = getContentPane();
		mainContentPane.setSize(new Dimension(500,500));
		mainContentPane.setLayout(new BorderLayout());
		mainContentPane.setBackground(Color.GRAY);
 
		displayPanel = new DisplayPanel();
		mainContentPane.add(displayPanel, BorderLayout.CENTER);
 
		validate();
 
	}
 
	public void start() {
 
	}
 
	public void paint(Graphics g) {
 
	}
}
 
class DisplayPanel extends JPanel {
 
	private int height, width;
 
	public DisplayPanel() {
		super();
		height = getHeight();
		width = getWidth();
	}
 
	public void paint(Graphics g) {
		g.drawRect(0,0,width-1,height-1);
	}
}

What is the empty paint method for
What is the width and height of the DisplayPanel?

                height = getHeight();
		width = getWidth();

height and width are = 0

when you call getHeight() and getWidth() when extending a Swing Component like a JPanel one(you can see this typical coding elsewhere), you should always be aware of values that these methods return, and by looking at your code, it seems like your attempting to create a custom component via JPanel as a container for other components.., well, be careful on customizing one, because you might end with messing up painting things, if that is your goal, you might consider looking on Google samples.