This tutorial will introduce you to mouse events in Java. You will learn how to program a cursor tracker, which triggers on events such as mouse button pressed, released, clicked, dragged, moved, etc.

Before reading this article you need to know:

1. Basic Java

2. Swing

3. Some knowledge of events in Java

Introduction to mouse events

An event is an action taking place with respect to a reference point. Java makes it very easy do detect mouse events. Mouse events include pressing, releasing, clicking of mouse (clicking as in pressing and then releasing the mouse button), cursor entering the application form, cursor leaving the application form, reporting of mouse cursor being dragged and reporting of mouse cursor being moved within the application.They are declared as:

public void mousePressed( MouseEvent event );

public void mouseReleased( MouseEvent event );

public void mouseClicked( MouseEvent event );

public void mouseEntered( MouseEvent event );

public void mouseExited( MouseEvent event );

public void mouseDragged( MouseEvent event );

public void mouseMoved( MouseEvent event );

Programming a mouse cursor tracker

The algorithm for building a mouse cursor tracker application is easy, first we have to setup a “Jlabel” at the bottom of the application form which acts as status bar, then we detect mouse events taking place; for each event we set different text strings for the “Jlabel” statusbar.

The code

First we declare packages we will be making use of during the program.

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

Second we simply declare a public class MouseTracker in which MouseListener and MouseMotionListener is implemented; Next a JLable with name Statusbar is declared. Further, a public function MouseTracker is declared and its title is set.

public class MouseTracker extends JFrame implements MouseListener, MouseMotionListener

{

   private JLabel statusbar;

   public MouseTracker()

   {

      super( "Mouse Tracker" );

      statusbar = new JLabel();

Now we position the Jlabel statusbar to south (i.e. bottom of the application) and add MouseMotionListener and MouseListener. Than we set its size and its visibility to true.

getContentPane().add( statusbar, BorderLayout.SOUTH );



      addMouseListener( this );

      addMouseMotionListener( this);



      setSize( 500, 500);

      setVisible( true );

   }

Now we just put in all the mouse events, and set different text for Jlabel Statusbar for different mouse events through the statement “statusbar.setText”. In “statusbar.setText” we’ve also used getX() and getY() which gives us the value of x and y coordinates where the event is taking place.

public void mouseClicked( MouseEvent event )

   {

      statusbar.setText( "Clicked @ x" + event.getX() + " y" + event.getY() );

   }

   public void mousePressed( MouseEvent event)

   {

      statusbar.setText( "Pressed @ x" + event.getX() + " y" + event.getY() );

   }

   public void mouseReleased( MouseEvent event )

   {

      statusbar.setText( "Released @ x" + event.getX() + " y" + event.getY() );

   }

   public void mouseEntered( MouseEvent event )

   {

      statusbar.setText( "Mouse Entered @ x" + event.getX() + " y" + event.getY() );

   }

   public void mouseExited( MouseEvent event )

   {

      statusbar.setText( "Mouse Exited @ x" + event.getX() + " y" + event.getY() );

   }

   public void mouseDragged( MouseEvent event )

   {

      statusbar.setText( "Mouse Dragged @ x" + event.getX() + " y" + event.getY() );

   }

   public void mouseMoved( MouseEvent event )

   {

      statusbar.setText( "Mouse Moved @ x" + event.getX() + " y" + event.getY() );

   }

Finally, in the lines below we have declared a MouseTracker class inside main and set it up to close the application:

public static void main( String args[] )

{

   MouseTracker application = new MouseTracker();

   application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

}