I am new to Java and need help. I am making a GUI for an application using images made from photoshop, and want to create a menu using images which highlights when user hover mouse over them. I have tried mouseEntered();
method by getting mouse x, y co-ordinates but it's not working. Here is the code.
public class GUI extends JComponent{
public void paintComponent(Graphics g){
super.paintComponent(g);
ImageIcon exitBtnImg = new ImageIcon("src/images/userInterface/exitBtn.png");
g.drawImage(exitBtnImg.getImage(), 0, 5, this);
mouseHandler handler = new mouseHandler();
addMouseListener(handler);
}
}
public class mouseHandler implements MouseListener{
@Override
public void mouseClicked(MouseEvent e) {
}
@Override
public void mousePressed(MouseEvent e) {
}
@Override
public void mouseReleased(MouseEvent e) {
}
@Override
public void mouseEntered(MouseEvent e) {
if((e.getX()>100&&e.getX()<300)&&(e.getY()>50&&e.getY()<196)){
repaint();
}
}
@Override
public void mouseExited(MouseEvent e) {
}
}
paintComponent
, your paint method should run as fast as it canpaint
methods, this will get called a lot, so you're just repeatedly adding new listeners each time your component is paintedMouseMotionListener
instead of a MouseListener
, you want the mouseMoved
eventHave a look at How to Write a Mouse-Motion Listener and Painting in AWT and Swing for more details.
This example uses a simple Rectangle
to define the location that the image is painted within, when the mouse moves within the confines of that Rectangle
, a flag is set and the component is repainted, which paints a alpha based highlight effect over the image
import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Example {
public static void main(String[] args) {
new Example();
}
public Example() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
ex.printStackTrace();
}
}
});
}
public class TestPane extends JPanel {
private BufferedImage img;
private Rectangle drawRectangle;
private boolean highlight = false;
public TestPane() throws IOException {
img = ImageIO.read(...);
addMouseMotionListener(new MouseAdapter() {
@Override
public void mouseMoved(MouseEvent e) {
highlight = drawRectangle.contains(e.getPoint());
repaint();
}
});
int width = getPreferredSize().width;
int height = getPreferredSize().height;
int x = (width - img.getWidth()) / 2;
int y = (height - img.getHeight()) / 2;
drawRectangle = new Rectangle(x, y, img.getWidth(), img.getHeight());
}
@Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.drawImage(img, drawRectangle.x, drawRectangle.y, this);
if (highlight) {
g2d.setColor(Color.RED);
g2d.setComposite(AlphaComposite.SrcOver.derive(0.5f));
g2d.fill(drawRectangle);
}
g2d.dispose();
}
}
}
Now, having said all that, you might be better off using the rollover
capabilities of JButton
, which will basically do the same thing.
See How to Use Buttons, Check Boxes, and Radio Buttons for more details