Why JSlider event listener no response?

Question

Thanks,
hi, the JSlider does exist, but when it slides, data is unchanged.
Please help.
import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.util.Hashtable;
import java.awt.event.*;
import javax.swing.event.*;
// import AppletAndApplicationExample.AppQuitter;
public class Combox extends JApplet
    private LayoutManager Layout;
    private Container Panel;
    private Drawing drawing;
  ..    private String energyId[];
    private int numberofCells;
    private int numberofsets;
    private int id; //PlotEnergyId
    private double lineWidth;
    private int min = 1, max = 16, inc = 5;
    double scale = 1.0;
    private String currentPattern;
    private JSlider dJSlider;
      public void init() {
         Layout = new BorderLayout ();
         getDrawingData();                               
                dJSlider = new JSlider(min, max, 6);
                drawing = new Drawing();
        Panel = getContentPane();
        Panel.setLayout (Layout);
        Panel.add (drawing, "Center");
        JPanel sliderPanel = new JPanel();
        sliderPanel.setLayout(new BoxLayout(sliderPanel,
                               BoxLayout.PAGE_AXIS));
                        dJSlider.setAlignmentX(Component.LEFT_ALIGNMENT);
        sliderPanel.add(dJSlider);
        dJSlider.setMajorTickSpacing(5);
        dJSlider.setMinorTickSpacing(1);
        dJSlider.setSnapToTicks(true);
        dJSlider.setLabelTable(getLabelTable(min, max, inc));
        dJSlider.setPaintTicks(true);
        dJSlider.setPaintLabels(true);
        dJSlider.addChangeListener(
                new ChangeListener() // anonymous inner class
                // handle change in slider value
                    public void stateChanged(ChangeEvent e)
                       int value = ((JSlider)e.getSource()).getValue();
                       scale = (value+4)/10.0;
                    Panel.add(sliderPanel,BorderLayout.NORTH); // ADD Slider
                    scaleData(); // use JSlider to obtain new data
                    System.out.println(scale);// found unchaged data,scale =1,why???
     private Hashtable getLabelTable(int min, int max, int inc) {
        Hashtable<Integer, JLabel> table = new Hashtable<Integer, JLabel>();
        for(int j = min; j <= max; j+=inc) {
            String s = String.format("%.1f", (j+4)/10.0);
            table.put(Integer.valueOf(j), new JLabel(s));
        return table;
    public void getDrawingData()
    public void scaleData()
        for(int i = 0; i < numberofCells; i++)
              for(int j = 0; j<cellsPointsNumber; j++)
xCells[i][j] = (xCells[i][j])*scale+TRANSITION;
yCells[i][j] = (yCells[i][j])*scale+TRANSITION;
public static void main(String[] args) {
/* Set up the frame that holds the applet. */
JFrame appletFrame = new JFrame("My Applet");
Applet theApplet = new Combox();
appletFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
appletFrame.setSize(800,800);
appletFrame.add(theApplet, "Center"); // applet fills
// frame
/* Now start invoking applet methods. */
theApplet.init();
// applet
appletFrame.show(); // bring frame and initialized
// applet on screen
theApplet.start();
theApplet.stop();
theApplet.destroy();
} // end class 

Answer 1

System.out.println(scale);// [b]found unchaged data,scale =1,why???[/b]scale is 1 because you set it to 1.0 initially and you never changed it. Notice that this line is executed just once in the init() method. It is not part of the change listener.