Want to show a "Please Wait" message while processing

Question

Hi,
I'm developing an image-processing tutorial applet where the user selects an image and then sets some parameters before pressing an update button which will run a JPEG compression on the image and show the compressed image.
The compression takes a few seconds, so I want the program to show an image saying "Please wait" in the position that the compressed image will appear while the compression is done.
Here is the relevant code:
public void paint (Graphics g) {
  if (updating) {
    updating = false;
    g.setColor(getBackground ());
    g.fillRect(575, 370, 250, 250); //clear the area where the image will appear
    g.setColor(Color.white);
    g.drawImage(updatingImg, 575, 370, 250, 250, this); //updatingImg just displays a "Please Wait" message
    doImage = true;
  if (doImage) {
    doImage = false;
    //perform the compression to get the new image and then show it
    newImg = imagetest.compressImage(origImg, quantizationMat);          
    g.setColor(getBackground ());
    g.fillRect(575, 370, 250, 250);
    g.setColor(Color.white);
    g.drawImage(newImg, 575, 370, 250, 250, this);
public void actionPerformed(ActionEvent evt) {
  if (evt.getSource() == update){
    //perform some error checking
    if (errorFound == false){
      updating = true;
      repaint();
}The problem is that the "Please wait" image never gets shown.. while the compression is carried out that part of the screen remains blank and then the new image is shown.
Can anyone tell me how to fix this?
Thanks.

Answer 1

Never mind, I've figured it out.. needed to put the time consuming code in a new thread.