In this example we are going to see how you can use the MouseListener interface in Java, in order to monitor the mouse activity on your application. This is very useful when you wan to add extra functionality to you application and make it more agile, when you make it possible for the user to interact with it using the mouse.
It’s very easy to use a MouseListener. All you have to do is:
- Create a new
MouseListener. - Override the methods that correspond to the mouse events you want to monitor, e.g
mouseClicked,mouseEntered,mouseExited,mousePressed,mouseReleasedetc. - Use the
addMouseListenermethod of your component to monitor the mouse activity that occurs on it.
Let’s see the code:
package com.javacodegeeks.snippets.desktop;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
public class MouseListenerExample extends JFrame {
int startX, startY, endX, endY;
Color red_col = Color.red;
public MouseListenerExample() {
super();
final JPopupMenu popMenu = new JPopupMenu();
popMenu.add(new JMenuItem("Cut"));
popMenu.add(new JMenuItem("Copy"));
popMenu.add(new JMenuItem("Paste"));
popMenu.addSeparator();
popMenu.add(new JMenuItem("Select All"));
popMenu.setInvoker(this);
MouseListener popup = new MouseListener() {
@Override
public void mouseClicked(MouseEvent event) {
}
@Override
public void mouseEntered(MouseEvent event) {
}
@Override
public void mouseExited(MouseEvent event) {
}
@Override
public void mousePressed(MouseEvent event) {
if (event.isPopupTrigger()) {
popMenu(event);
}
}
@Override
public void mouseReleased(MouseEvent event) {
if (event.isPopupTrigger()) {
popMenu(event);
}
}
private void popMenu(MouseEvent event) {
popMenu.show(event.getComponent(), event.getX(), event.getY());
}
};
addMouseListener(popup);
MouseListener drawing1 = new MouseListener() {
@Override
public void mouseClicked(MouseEvent event) {
}
@Override
public void mouseEntered(MouseEvent event) {
}
@Override
public void mouseExited(MouseEvent event) {
}
@Override
public void mousePressed(MouseEvent event) {
red_col = Color.RED;
startX = endX = event.getX();
startY = endY = event.getY();
repaint();
}
@Override
public void mouseReleased(MouseEvent event) {
red_col = Color.BLACK;
repaint();
}
};
addMouseListener(drawing1);
MouseMotionListener drawing2 = new MouseMotionListener() {
@Override
public void mouseDragged(MouseEvent event) {
endX = event.getX();
endY = event.getY();
repaint();
}
@Override
public void mouseMoved(MouseEvent event) {
}
};
addMouseMotionListener(drawing2);
}
@Override
public void paint(Graphics graphic) {
super.paint(graphic);
graphic.setColor(red_col);
graphic.drawLine(startX, startY, endX, endY);
}
public static void main(String args[]) {
JFrame jFrame = new MouseListenerExample();
jFrame.setSize(600, 400);
jFrame.setVisible(true);
}
}
This was an example on how to use MouseListener in Java.
