Prentice.Hall.Introduction.to.Java.Programming,.Brief.Version.9th.(2014).[sharethefiles.com]

624 Chapter 16 Event-Driven Programming
create/register listener
request focus
request focus
left button?
right button?
UP pressed?
DOWN pressed?
8 private CirclePanel canvas = new CirclePanel();
9
10 public ControlCircleWithMouseAndKey() {
11 JPanel panel = new JPanel(); // Use the panel to group buttons
12 panel.add(jbtEnlarge);
13 panel.add(jbtShrink);
14
15 this.add(canvas, BorderLayout.CENTER); // Add canvas to center
16 this.add(panel, BorderLayout.SOUTH); // Add buttons to the frame
17
18 jbtEnlarge.addActionListener(new ActionListener() {
19 @Override
20 public void actionPerformed(ActionEvent e) {
21 canvas.enlarge();
22
23
canvas.requestFocusInWindow();
}
24 });
25
26 jbtShrink.addActionListener(new ActionListener() {
27 @Override
28 public void actionPerformed(ActionEvent e) {
29 canvas.shrink();
30
31
canvas.requestFocusInWindow();
}
32 });
33
34 canvas.addMouseListener(new MouseAdapter() {
35 @Override
36 public void mouseClicked(MouseEvent e) {
37
38
if (e.getButton() == MouseEvent.BUTTON1)
canvas.enlarge();
39
40
else if (e.getButton() == MouseEvent.BUTTON3)
canvas.shrink();
41 }
42 });
43
44
45
canvas.setFocusable(true);
canvas.addKeyListener(new KeyAdapter() {
46 @Override
47 public void keyPressed(KeyEvent e) {
48
49
if (e.getKeyCode() == KeyEvent.VK_UP)
canvas.enlarge();
50
51
else if (e.getKeyCode() == KeyEvent.VK_DOWN)
canvas.shrink();
52 }
53 });
54 }
55
56 /** Main method */
57 public static void main(String[] args) {
58 JFrame frame = new ControlCircleWithMouseAndKey();
59 frame.setTitle("ControlCircle");
60 frame.setLocationRelativeTo(null); // Center the frame
61 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
62 frame.setSize(200, 200);
63 frame.setVisible(true);
64 }
65
66 class CirclePanel extends JPanel { // Inner class
67 private int radius = 5; // Default circle radius