Swing I - Absolute Java - page 991

Display 17.16 Listeners as Inner Classes (part 1 of 2)

<Import statements are the same as in Display 17.14.>

1 public class InnerListenersDemo extends JFrame
2 {
3 public static final int WIDTH = 300;

4 public static final int HEIGHT = 200;

5 private JPanel bluePanel;

6 private JPanel whitePanel;

7 private JPanel grayPanel;

8 private class blueListener implements ActionListener
9 {
10 public void actionPerformed(ActionEvent e)
11 {
12 bluePanel.setBackground(Color.BLUE);
13 }
14 } //End of greenListener inner class

15 private class WhiteListener implements ActionListener
16 {
17 public void actionPerformed(ActionEvent e)
18 {
19 whitePanel.setBackground(Color.WHITE);
20 }
21 } // End of WhiteListener inner class
22 private class grayListener implements ActionListener
23 {
24 public void actionPerformed(ActionEvent e)
25 {
26 grayPanel.setBackground(Color.GRAY);
27 }
28 } // End of grayListener inner class

29 public static void main(String[] args)
30 {
31 InnerListenersDemo gui = new InnerListenersDemo();
32 gui.setVisible( true );
33 }

34 public InnerListenersDemo()
35 {
36 super ("Menu Demonstration");
37 setSize(WIDTH, HEIGHT);
38 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
39 setLayout( new GridLayout(1, 3));

The resulting GUI is the same as in
Display 17.14

(continued)