Thread: Java GUI problem in paintComponent?

Hi everyone. I can't seem to get my java code to work. I suspect it's a problem with the way I've coded my paintComponent methods, but for the life of me I can't figure out where the problem is.

Instead of drawing a pretty picture on screen, all I get is a vast expanse of nothing. Any/all input would be greatly appreciated Oh, and yes - the image file is definitely in the correct directory.

import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Image;
 
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
public class FrontEnd extends JFrame {
 
	public FrontEnd() {
		Image miniIcon = new ImageIcon("icon.gif").getImage();
		this.setIconImage(miniIcon);
		MainScreen mainScr = new MainScreen();
		add(mainScr);
		mainScr.repaint();
	}
 
	public static void main(String args[]) {
		FrontEnd window = new FrontEnd();
		window.setTitle("Blah");
		window.setSize(400, 400);
		window.setLocationRelativeTo(null);
		window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		window.setVisible(true);
 
	}
 
}
 
//#####################################################################################################
 
class MainScreen extends JPanel {
 
	public MainScreen() {
 
		JPanel p = new JPanel(new GridLayout(1, 1, 0, 0));
		System.out.println("Container panel created");
 
		Image image = new ImageIcon("icon.gif").getImage();
		ImageViewer viewPanel = new ImageViewer(image);
		add(viewPanel);
		viewPanel.repaint();		
 
	}
 
	protected void paintComponent(Graphics g) {
		ImageViewer.repaint();
		System.out.println("The main screen is redrawn");
	}
 
 
}
 
//#####################################################################################################
 
class ImageViewer extends JPanel {
 
	private java.awt.Image image;
 
	public ImageViewer(Image image) {
		this.image = image;	
		System.out.println("ImageViewer constructor called");
	}
 
	protected void paintComponent(Graphics g) {
		super.paintComponent(g);
		g.drawImage(image, 0, 0, this);
		System.out.println("ImageViewer paintComponent called");
	}
 
}

ImageViewer.repaint();

What is it you hope to redraw when you call this? Becuase as far as I am aware, that is COMPLETELY Illegal. The only way to call repaint is on an instance not class, ie as a static function.

repaint is definded as
public void repaint();

not,
public static void repaint();

thus it cannot be called in a static manner.
This is confusing to explain lol. One last try,

You cannot call a non-static function on a class, you must call it on an instance of a class.

Regards,
Chris