Java Swing Tutorial - Java MouseWheelEvent .getPreciseWheelRotation ()

Syntax

MouseWheelEvent.getPreciseWheelRotation() has the following syntax.

public double getPreciseWheelRotation()

Example

In the following code shows how to use MouseWheelEvent.getPreciseWheelRotation() method.

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
/*from   ww  w  .  j ava  2s .  c  om*/
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class Main extends JPanel implements MouseWheelListener {
  JTextArea textArea = new JTextArea();

  JScrollPane scrollPane = new JScrollPane(textArea);

  public Main() {
    super(new BorderLayout());
    textArea.setEditable(false);
    
    scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
    scrollPane.setPreferredSize(new Dimension(400, 250));
    add(scrollPane, BorderLayout.CENTER);
   
    textArea.addMouseWheelListener(this);

    setPreferredSize(new Dimension(450, 350));
    setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
  }
  public void mouseWheelMoved(MouseWheelEvent e) {
    double rotation= e.getPreciseWheelRotation();
    System.out.println(rotation);
  }
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JComponent newContentPane = new Main();
    newContentPane.setOpaque(true);
    frame.setContentPane(newContentPane);

    frame.pack();
    frame.setVisible(true);
  }
}