Update JProgressBar | 易学教程

问题

I can't update my progressbar... this is my code

Thread t=new Thread(new Runnable(){
        public void run(){
            int i=1;
            jProgBar.setMinimum(0);
            jProgBar.setMaximum(100);
            try {
                while(i<=100 || true){
                    jProgBar.setValue(i);
                    i++;
                    Thread.sleep(50);
                }
            }
            catch (InterruptedException ex){
                jProgBar.setValue(jProgBar.getMaximum());
            }
        }
    });
    t.start();

    .... Something code that correctly works

    t.interrupt();

The progress bar state is updated only at the end of thread. Can someone help me??

回答1:

Before the sleep, add a call to SwingUtilties.invokeLater() that spawns a thread to fire a firePropertyChange on the progressbar in the EDT.

回答2:

Use a model instead of the JProgressBar directly:

DefaultBoundedRangeModel model = new DefaultBoundedRangeModel();
JProgressBar bar = new JProgressBar(model);

// Somewhere else, perhaps in another Thread
model.setValue(i)

The following example works fine:

public static void main(String[] args) throws InterruptedException {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(200, 100);
    frame.setVisible(true);
    final DefaultBoundedRangeModel model = new DefaultBoundedRangeModel();
    frame.add(new JProgressBar(model));
    Thread t = new Thread(new Runnable() {
        public void run() {
            int i = 1;
            model.setMinimum(0);
            model.setMaximum(100);
            try {
                while (i <= 100 || true) {
                    model.setValue(i);
                    i++;
                    Thread.sleep(50);
                }
            } catch (InterruptedException ex) {
                model.setValue(model.getMaximum());
            }
        }
    });
    t.start();

    Thread.sleep(2000);

    t.interrupt();
}

回答3:

The best advice for your situation is to use SwingWorker. Check out the API at http://java.sun.com/javase/6/docs/api/javax/swing/SwingWorker.html

Override process method to update value of progress bar ( then it will be done correctly on EDT)

More info can be obtained at http://java.sun.com/products/jfc/tsc/articles/threads/threads2.html

回答4:

Per eugener, SwingWorker is definitely what you want to be using here, or any time a long-running task is spawned that could otherwise lock up your GUI prior to completion. A full tutorial on using progress bars with SwingWorker is available from Sun^H^H^HOracle here:

http://java.sun.com/docs/books/tutorial/uiswing/components/progress.html

回答5:

Thanks All. I solved in this way

try{
       jProgBar.setIndeterminate(true);
       jProgBar.setStringPainted(true);
       jProgBar.setBorderPainted(true);
       new Thread(new Runnable() {
           public void run() {
               ...
               // here is code that i've to wait
               // after this i stop my jProgressBar
               ...
               jProgBar.setStringPainted(false);
               jProgBar.setBorderPainted(true);
               jProgBar.setIndeterminate(false);
       }
       }).start();
   }
   catch(IllegalStateException ex){
       //some code
   }

回答6:

Putting this snippet

SwingUtilities.invokeLater(new Runnable() {
    public void run() {
        jProgBar.repaint();
    }
}

Between 'i++' and 'Thread.sleep()' should do the job. To get it compiling, mark jProgBar as 'final'.

来源：https://stackoverflow.com/questions/3174613/update-jprogressbar

标签

java

swing

multithreading

jprogressbar

runnable