Java - repaint component every second?

Question

I would like to repaint component after each second, but it didn't work. What I am trying is:

    try{
        while(true){
            Thread.currentThread().sleep(1000);
            gc.cb.next();
            gc.repaint();
        }
    }
    catch(Exception ie){
    }

Answer 1

I would advise using a javax.swing.Timer for this problem, which will periodically fire an ActionEvent on the Event Dispatch thread (note that you should only call repaint and / or manipulate Swing components from this thread). You can then define an ActionListener to intercept the event and repaint your component at this point.

Example

JComponent myComponent = ...
int delay = 1000; //milliseconds

ActionListener taskPerformer = new ActionListener() {
  public void actionPerformed(ActionEvent evt) {
    myComponent.repaint();
  }
};

new Timer(delay, taskPerformer).start();

Also note that SwingWorker is probably inappropriate as it is typically used for background tasks that have a defined start and end, rather than a periodic task.

Answer 2

Make sure you're not hogging the UI-thread for this. If you're executing this loop in the UI-thread, then the repaint event will never be dispatched.

Another note; sleep is a static method, and should be invoked as Thread.sleep(...) . (There is no way of doing thatThread.sleep(...) anyway.)

The "correct" way of doing this is probably to use a SwingWorker . Have a look at the tutorial .

If you provide more code, we can provide better answers.