Moved from Processing with Other Languages, since you use Java.

See http://wiki.processing.org/w/Wheel_mouse
But it is also directly supposed in 2.0: http://processing.org/reference/mouseWheel_.html

Thanks for the quick reply. But I also found this code in this forum.

1. /**
   Wheel mouse taken from http://wiki.processing.org/index.php/Wheel_mouse
   @author Rick Companje
   */
   
   package main;
   
   import java.awt.event.*;
    
   void setup()    <--------- Error message
   {
     addMouseWheelListener(new MouseWheelListener() {
       public void mouseWheelMoved(MouseWheelEvent mwe) {
         mouseWheel(mwe.getWheelRotation());
     }});
   }
    
   void mouseWheel(int delta)
   {
     println("mouse has moved by " + delta + " units.");
   }
    
   void draw()
   {
    
   }
   

Multiple markers at this line
    - Syntax error on token "void", @ expected
    - Syntax error, insert "enum Identifier" to complete EnumHeader

I work with ControlP5 elements

Thank you for your patience.
Willi

I've come a bit further, but it does not work.

1. /**
   Wheel mouse taken from http://wiki.processing.org/index.php/Wheel_mouse
   @author Rick Companje
   */
   
   package main;
   
   import java.awt.event.*;
   import java.awt.Frame;
   import java.awt.*;
   
   import processing.core.*;
   import controlP5.*;
   
   import javax.swing.*;
   
   public class Maus01 extends PApplet{
      
       PApplet parent;
      
       // classes
       ControlP5 cp5;
    
       public void setup() {
         size(400, 300);
         cp5        = new ControlP5(this);
            
         cp5.addNumberbox("numberbox")
            .setPosition(20, 20)
            .setSize(100, 20)
            ;
        
         addMouseWheelListener(); 
       }
          
       public void draw()
       {
         background(0);
       }
   
       public void controlEvent(ControlEvent event) {
             println(event);
       }
      
       void addMouseWheelListener() {
             frame.addMouseWheelListener(new java.awt.event.MouseWheelListener() {
               public void mouseWheelMoved(java.awt.event.MouseWheelEvent e) {
                 cp5.setMouseWheelRotation(e.getWheelRotation());
               }
             }
             );
       }
   }
   

I(?) solved the problem.

1. package main;
   
   import processing.core.*;
   import controlP5.*;
   
   public class Maus01 extends PApplet{
      
       PApplet parent;
      
       // classes
       ControlP5 cp5;
    
       public void setup() {
         size(400, 300);
         cp5        = new ControlP5(this);
            
         cp5.addNumberbox("numberbox")
            .setPosition(20, 20)
            .setSize(100, 20)
            ;
        
         cp5.addNumberbox("numberbox2")
            .setPosition(20, 100)
            .setSize(100, 20)
            ;
              
        
         addMouseWheelListener(new java.awt.event.MouseWheelListener() {
               public void mouseWheelMoved(java.awt.event.MouseWheelEvent e) {
                 cp5.setMouseWheelRotation(e.getWheelRotation());
               }
             });
       } 
       public void draw()
       {
         background(0);
       }
       public void controlEvent(ControlEvent event) {
             println(event);
       }
   }