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| public class MyMouseListener implements MouseListener {
public void mouseClicked(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
}
public class MyMouseMotionListener implements MouseMotionListener {
public void mouseDragged(MouseEvent me) {
}
public void mouseMoved(MouseEvent me) {
}
}
public class MyKeyListener implements KeyListener {
public void keyPressed(KeyEvent key) {
}
public void keyReleased(KeyEvent key) {
}
public void keyTyped(KeyEvent key) {
}
} |
You can of course combine them:
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| public class MySuperAwesomeListener implements MouseListener, MouseMotionListener, KeyListener {
....
} |
And you can also use an Adapter to only use certain methods you need:
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| public class MyMouseListener extends MouseAdapter {
} |
MouseListener -> MouseAdapter
MouseMotionListener -> MouseMotionAdapter
KeyListener -> KeyAdapter
Do note that Java is a single-inheritance language, which means a class can only extend 1 class but can implement as many interfaces as it wants.
To add a listener:
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| JComponent component = new MyCustomJComponent();
component.addMouseListener(new MyMouseListener());
component.addMouseMotionListener(new MyMouseMotionListener());
component.addKeyListener(new MyKeyListener()); |
You can also use the anonymous inner class syntax to create quick listeners:
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| component.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent key) {
if(key.getKeyCode() == KeyEvent.VK_ENTER)
System.out.println("YOU PRESSED ENTER!!");
}
}); |
To load an image, you use the javax.imageio.ImageIO class:
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| BufferedImage image = ImageIO.read(getClass().getClassLoader().getResource("res/images/MyImage.png")); |
getResource(String) takes a path that is relative to the working directory, or the root, of the project. This means in Eclipse, the root is the "bin" folder. In a JAR file, the root is the root of the JAR file or the folder it's in.
