Question

I have a progressbar in a.java class(in form).I need to reach it from b.java class .
My progressbar name is jprog.(I put it in form from palet)
How can I set public my progressbar? I cant find it in properties page.
my progressbarr in first class. But I want to change its value in second class.
Thanks.

Answer 1

Consider adding a PropertyChangeListener to your first class and using a SwingWorker in your second class. SwingWorker has a method called setProgress() that you can invoke to set the value of your progress bar. You can then override the propertyChange() method in your first class and do something like this:

public void propertyChange(PropertyChangeEvent evt) {
    if ("progress" == evt.getPropertyName()) {
      int progress = (Integer) evt.getNewValue();
      progressBar.setValue(progress);
    }
}

An example using a couple of classes, ClassA and ClassB can be as follows:

public ClassA extends JForm implements PropertyChangeListener{
    private JProgressBar progressBar;

    public ClassA(){
        /**
        * Your setup for the form
        */
    }

     /**
     * Invoked when task's progress property changes.
     */
    public void propertyChange(PropertyChangeEvent evt) {
        if ("progress" == evt.getPropertyName()) {
            int progress = (Integer) evt.getNewValue();
            progressBar.setValue(progress);
        }
    }

    public void someMethod(){
        ClassB classB = new ClassB();
        classB.addPropertyChangeListener(this);
        classB.execute();
    }
}

class ClassB extends SwingWorker<Void, Void> {
        /*
         * Main task. Executed in background thread.
         */
        @Override
        public Void doInBackground() {
            Random random = new Random();
            int progress = 0;
            //Initialize progress property.
            setProgress(0);
            //Sleep for at least one second to simulate "startup".
            try {
                Thread.sleep(1000 + random.nextInt(2000));
            } catch (InterruptedException ignore) {}
            while (progress < 100) {
                //Sleep for up to one second.
                try {
                    Thread.sleep(random.nextInt(1000));
                } catch (InterruptedException ignore) {}
                //Make random progress.
                progress += random.nextInt(10);
                setProgress(Math.min(progress, 100));
            }
            return null;
        }
}