JProgressBar and threads?

[Kevin Schneider]

i am writing a simple file transfer app and i'd like to add a progress bar. however, the problem i'm having is that the bar doesnt update until the transfer is finished.
here is what my methods look like:

protected void setProgressValue(final int value) {
  Runnable runner = new Runnable() { 
public void run() {
  progressBar.setValue(value);
}
  };
  SwingUtilities.invokeLater(runner);
}

protected void setProgressMaximum(final int value) {
  Runnable runner = new Runnable() { 
public void run() {
  progressBar.setMaximum(value);
}
  };
  SwingUtilities.invokeLater(runner);
}

and here is where i call these methods during the transfer:

setProgressMaximum(fileSize);
....
while ((bytesRead = fis.read(buffer)) != -1) {  
os.write(buffer, 0, bytesRead);
kbSent++;
setProgressValue(kbSent);
}

[ October 23, 2003: Message edited by: Kevin Schneider ]

[kyle amburn]

Hi-
Try the following code:

  
protected int progressValue = 0;//store current value as a instance var
protected int progressMax = 1;
protected void updateProgressBar(){
Thread runner = new Runnable(){
while (progressValue < progressMax){
progressBar.setValue(progressValue);
try{
                                //choose an acceptable pause time
Thread.sleep(100);
}catch (nterruptedException e){}
} 
});
runner.start();
} 

protected synchronized void setProgressValue(int value){
progressValue = value;
}
protected synchronized void setProgressMaximum(int value){
progressMax = value;
}

I am not sure why you threaded the setting of the maximum value, unless it changes often. You may also want to add some code to pause your file transfer momentarily every few milliseconds to ensure that the thread updating the progress bar has a chance to execute.
Hope this helps.
Kyle