Multiple Threads Problem

Question

Hi,
I am new to Java Threading and the current program that I am working is having problems. The program basically paints lines and dots or onto a JPanel which displays an image. There exists a thread here to suspend and resume the drawing at the user's disposal. This part works flawlessly.
Now since the images are quite large I have attempted to add a JWindow to the JFrame to indiate that the image is loading. And here lies my problem, the JWindow which also contains a paint method does not display anything until after the image is fully loaded onto the JPanel.
Can someone please tell me what I am doing wrong and how to implement this?
Thanks, James
Here is how my program is structured:
public class Proj extends JFrame
public Proj()
Display disp = new Display();
Thread thr1 = new Thread(disp);
thr1.start();
Container con = getContentPane();
con.add(vsr);
setSize(500,500);
show();
public static void main(String [] args)
{  new Proj();
class Display extends JPanel implements Runnable
public Display()
Loading ld = new Loading();
Thread thr2 = new Thread(ld);
ld.start();
// gets data and image files
ld.interrupt();
public void paintComponent(Graphics g)
// draws image, lines, circles etc.
public void run()
// involved with data to draw next image, lines etc.
class Loading extends JWindow implements Runnable
public void paint(Graphics g)
// displays loading animation
public void run()
// animation code

Answer 1

Since Swing is single-threaded, any painting activity after a component is realized/visible should be handled on the EDT (Event Dispatch Thread). The loading of data/files can be done on worker different thread. On the EDT you should fetch the status and paint your progress bar. If you paint the progress bar on the worker thread it would not work out the way you want. Try to also investigate into SwingUtilities.invokeLater method which allows us to put a code to be executed on the EDT.