Swing II - Java - page 965

Display 18.2 A Window Listener (part 1 of 3)

1 import javax.swing.JFrame;

2 import javax.swing.JPanel;

3 import java.awt.BorderLayout;

4 import java.awt.FlowLayout;

5 import java.awt.Color;

6 import javax.swing.JLabel;

7 import javax.swing.JButton;

8 import java.awt.event.ActionListener;

9 import java.awt.event.ActionEvent;

10 import java.awt.event.WindowListener;

11 import java.awt.event.WindowEvent;

12 public class WindowListenerDemo extends JFrame

13 {

14 public static final int WIDTH = 300; //for main window

15 public static final int HEIGHT = 200; //for main window

16 public static final int SMALL_WIDTH = 200; //for confirm window

17 public static final int SMALL_HEIGHT = 100; //for confirm window

18 private class CheckOnExit implements WindowListener

19 {

This WindowListener
class is an inner class.

20 public void windowOpened(WindowEvent e)

21 {}

22 public void windowClosing(WindowEvent e)

23 {

24 ConfirmWindow checkers = new ConfirmWindow();

25 checkers.setVisible( true );

26 }

27 public void windowClosed(WindowEvent e)

28 {}

29 public void windowIconified(WindowEvent e)

30 {}

31 public void windowDeiconified(WindowEvent e)

32 {}

A window listener must
define all the method
headings in the
WindowListener interface,
even if some are trivial
implementations.

33 public void windowActivated(WindowEvent e)

34 {}

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