How to use Mouse Events in Swing

Mouse events are generated by the following types of user interaction:

• A mouse click
• A mouse entering a component's area
• A mouse leaving a component's area

Any component can generate these events, and a class must implement MouseListener interface to support them.

The following example shows how to use mouse events in Swing:

import javax.swing.*;

import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.Insets;
import java.awt.Color;
import java.awt.Dimension;

import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;

public class MouseEventDemo extends JPanel
implements MouseListener {
BlankArea blankArea;
JTextArea textArea;
final static String newline = "\n";

public MouseEventDemo() {
super(new GridBagLayout());
GridBagLayout gridbag = (GridBagLayout)getLayout();
GridBagConstraints c = new GridBagConstraints();

c.fill = GridBagConstraints.BOTH;
c.gridwidth = GridBagConstraints.REMAINDER;
c.weightx = 1.0;
c.weighty = 1.0;

c.insets = new Insets(1, 1, 1, 1);
blankArea = new BlankArea(new Color(0.98f, 0.97f, 0.85f));
gridbag.setConstraints(blankArea, c);
add(blankArea);

c.insets = new Insets(0, 0, 0, 0);
textArea = new JTextArea();
textArea.setEditable(false);
JScrollPane scrollPane = new JScrollPane(textArea);
scrollPane.setVerticalScrollBarPolicy(
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setPreferredSize(new Dimension(200, 75));
gridbag.setConstraints(scrollPane, c);
add(scrollPane);

//Register for mouse events on blankArea and the panel.
blankArea.addMouseListener(this);
addMouseListener(this);

setPreferredSize(new Dimension(450, 450));
setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
}

public void mousePressed(MouseEvent e) {
saySomething("Mouse pressed (# of clicks: "
+ e.getClickCount() + ")", e);
}

public void mouseReleased(MouseEvent e) {
saySomething("Mouse released (# of clicks: "
+ e.getClickCount() + ")", e);
}

public void mouseEntered(MouseEvent e) {
saySomething("Mouse entered", e);
}

public void mouseExited(MouseEvent e) {
saySomething("Mouse exited", e);
}

public void mouseClicked(MouseEvent e) {
saySomething("Mouse clicked (# of clicks: "
+ e.getClickCount() + ")", e);
}

void saySomething(String eventDescription, MouseEvent e) {
textArea.append(eventDescription + " detected on "
+ e.getComponent().getClass().getName()
+ "." + newline);
textArea.setCaretPosition(textArea.getDocument().getLength());
}

/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);

//Create and set up the window.
JFrame frame = new JFrame("MouseEventDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

//Create and set up the content pane.
JComponent newContentPane = new MouseEventDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);

//Display the window.
frame.pack();
frame.setVisible(true);
}

public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}


import javax.swing.*;
import java.awt.Dimension;
import java.awt.Color;
import java.awt.Graphics;

public class BlankArea extends JLabel {
Dimension minSize = new Dimension(100, 100);

public BlankArea(Color color) {
setBackground(color);
setOpaque(true);
setBorder(BorderFactory.createLineBorder(Color.black));
}

public Dimension getMinimumSize() {
return minSize;
}

public Dimension getPreferredSize() {
return minSize;
}
}