How do I call an actionlistener while the slider is moving, not just when I let go of the mouse?

class AngleSlider开发者_Go百科 implements ChangeListener {
        public void stateChanged(ChangeEvent e) {
        JSlider source = (JSlider) e.getSource();
        if (!source.getValueIsAdjusting()) {

            double dAngle = (double)source.getValue();
            pnlCannon.dCannonAngle=Math.toRadians(dAngle);
            pnlCannon.repaint();

        }
    }
}

This is our current event listener. Is there a different listener required to do what I want?

No, you will only need to remove the getValueIsAdjusting() check. So, this will repaint your cannon when you move your mouse:

class AngleSlider implements ChangeListener {
    public void stateChanged(ChangeEvent e) {
        JSlider source = (JSlider) e.getSource();

        double dAngle = (double)source.getValue();
        pnlCannon.dCannonAngle=Math.toRadians(dAngle);
        pnlCannon.repaint();
    }
}

This is another example that shows the same, it will print the value of the slider as you move it:

public static void main(String[] args) {

    JFrame frame = new JFrame("Test");

    JSlider slider = new JSlider();

    slider.addChangeListener(new ChangeListener() {
        @Override
        public void stateChanged(ChangeEvent ce) {
            System.out.println(((JSlider) ce.getSource()).getValue());
        }
    });

    frame.add(slider);

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 300);
    frame.setVisible(true);
}

The !source.getValueIsAdjusting() is preventing the update code form executing.

Why do you think that condition is necessary?