mouse wheel listener not working in jscrollbar

Question

I am developing a desktop application in netbeans platform (netbeans module) in which i have a desktoppane and a jscrollbar. i have implemented MouseWheelListener and added

scrollBar.addMouseWheelListener(this);

in the constructor of the class. now when i am scrolling the wheel of mouse it do not scroll the scroll bar though i am getting values in the

 private void scrollBarMouseWheelMoved(java.awt.event.MouseWheelEvent evt) { 


 System.out.println("mouse value is------------ " + evt.paramString());
}

ouput of above sout is

mouse value is------------ MOUSE_WHEEL,(8,49),absolute(0,0),button=0,clickCount=0,scrollType=WHEEL_UNIT_SCROLL,scrollAmount=3,wheelRotation=1

what should i do now to enable mosue wheel event on jscrollbar?

I have searched but i found events for scrollpane but i am looking for scrollbar explicitly..

i have removed extra code and shown what i am looking for in the following sample code

    public final class ScrollableWindow1TopComponent extends TopComponent implements ComponentListener, MouseWheelListener {

    private javax.swing.JScrollBar scrollBar;
    private javax.swing.JDesktopPane scrollableGraphnewContainer;

    public ScrollableWindow1TopComponent() {
      this.addComponentListener(this);
      scrollBar.addMouseWheelListener(this);

    }
     private void scrollBarMouseWheelMoved(java.awt.event.MouseWheelEvent evt) {                                          
       System.out.println("mouse value is------------ " + evt.paramString());
    }
     private void scrollBarAdjustmentValueChanged(java.awt.event.AdjustmentEvent evt) { 
      //code that works fine 
    }
  }

Answer 1

my actual problem was that i was not getting the scroll value changed on mouse wheel change but i was getting the mouse wheel event so i have solved as follow:

 private void scrollBarMouseWheelMoved(java.awt.event.MouseWheelEvent evt) {                                          
        if (evt.getUnitsToScroll() > 0) {
            scrollBar.setValue(scrollBar.getValue() + 1);
        } else {
            scrollBar.setValue(scrollBar.getValue() - 1);
        }
   }      

everytime i scroll wheel up side evt.getUnitsToScroll() gives positive value and for down it gives negative value so i incremented the value of scrollbar and rest of thing are automatically handled by

  private void scrollBarAdjustmentValueChanged(java.awt.event.AdjustmentEvent evt) { 
     //my code...
}

Answer 2

I think that you have look at AdjustmentListener rather than MouseXxxListener,

final JScrollBar scrollBar = myScrollpane.getVerticalScrollBar();
scrollBar.addAdjustmentListener(new AdjustmentListener() {

    @Override
    public void adjustmentValueChanged(AdjustmentEvent e) {
        System.out.println("JScrollBar's current value = " + scrollBar.getValue());
    }
});

.

.

EDIT

:-) no, without any issue on my side :-)

import java.awt.*;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import javax.swing.*;

public class ListPanel extends JFrame {

    private static final long serialVersionUID = 1L;

    public ListPanel() {
        setLayout(new GridLayout(0, 2, 10, 10));
        DefaultListModel model = new DefaultListModel();
        model.addElement(createButtons("one"));
        model.addElement(createButtons("two"));
        model.addElement(createButtons("three"));
        model.addElement(createButtons("four"));
        model.addElement(createButtons("five"));
        model.addElement(createButtons("six"));
        model.addElement(createButtons("seven"));
        model.addElement(createButtons("eight"));
        model.addElement(createButtons("nine"));
        model.addElement(createButtons("ten"));
        model.addElement(createButtons("eleven"));
        model.addElement(createButtons("twelwe"));
        JList list = new JList(model);
        list.setCellRenderer(new PanelRenderer());
        JScrollPane scroll1 = new JScrollPane(list);
        final JScrollBar scrollBar = scroll1.getVerticalScrollBar();
        scrollBar.addAdjustmentListener(new AdjustmentListener() {

            @Override
            public void adjustmentValueChanged(AdjustmentEvent e) {
                System.out.println("JScrollBar's current value = " + scrollBar.getValue());
            }
        });
        add(scroll1);
        JScrollPane scroll2 = new JScrollPane(createPanel());
        add(scroll2);        
        final JScrollBar scrollBar1 = scroll2.getVerticalScrollBar();
        scrollBar1.addAdjustmentListener(new AdjustmentListener() {

            @Override
            public void adjustmentValueChanged(AdjustmentEvent e) {
                System.out.println("JScrollBar's current value = " + scrollBar1.getValue());
            }
        });

    }

    public static JPanel createPanel() {
        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(0, 1, 1, 1));
        panel.add(createButtons("one"));
        panel.add(createButtons("two"));
        panel.add(createButtons("three"));
        panel.add(createButtons("four"));
        panel.add(createButtons("five"));
        panel.add(createButtons("six"));
        panel.add(createButtons("seven"));
        panel.add(createButtons("eight"));
        panel.add(createButtons("nine"));
        panel.add(createButtons("ten"));
        panel.add(createButtons("eleven"));
        panel.add(createButtons("twelwe"));
        return panel;
    }

    public static JButton createButtons(String text) {
        JButton button = new JButton(text);
        return button;
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            public void run() {
                ListPanel frame = new ListPanel();
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                //frame.pack();
                frame.setSize(270, 200);
                frame.setVisible(true);
            }
        });
    }

    class PanelRenderer implements ListCellRenderer {

        public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
            JButton renderer = (JButton) value;
            renderer.setBackground(isSelected ? Color.red : list.getBackground());
            return renderer;
        }
    }
}

output from System.out.println(...)

run:
JScrollBar's current value = 0
JScrollBar's current value = 0
JScrollBar's current value = 1
JScrollBar's current value = 2
JScrollBar's current value = 3
JScrollBar's current value = 4
JScrollBar's current value = 5
JScrollBar's current value = 6
JScrollBar's current value = 7
JScrollBar's current value = 8
JScrollBar's current value = 9
JScrollBar's current value = 10
JScrollBar's current value = 11
JScrollBar's current value = 12
JScrollBar's current value = 13
JScrollBar's current value = 14
JScrollBar's current value = 15
JScrollBar's current value = 78
JScrollBar's current value = 143
JScrollBar's current value = 78
JScrollBar's current value = 0
JScrollBar's current value = 78
JScrollBar's current value = 143
BUILD SUCCESSFUL (total time: 10 seconds)

Answer 3

Had you tried adding setWheelScrollingEnabled(true/false), on your JScrollPane.