GUI BASICS - Introduction to Java Programming - page 467

Tip
A splash screen is an image that is displayed while the application is starting up. If your
program takes a long time to load, you may display a splash screen to alert the user. For
example, the following command:

splash screen

java -splash:image/us.gif TestImageIcon

displays an image while the program TestImageIcon is being loaded.

12.25 How do you create an ImageIcon from the file image/us.gif in the class directory?
12.26 Will the following code display three buttons? Will the buttons display the same icon?

✓ ✓

Check

Point

1 import javax.swing.*;

2 import java.awt.*;

3
4 public class Test extends JFrame {
5 public static void main(String[] args) {
6 // Create a frame and set its properties
7 JFrame frame = new Test();
8 frame.setTitle( "ButtonIcons" );
9 frame.setSize( 200 , 100 );
10 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
11 frame.setVisible( true );
12 }
13
14 public Test() {
15 ImageIcon usIcon = new ImageIcon( "image/us.gif" );
16 JButton jbt1 = new JButton(usIcon);
17 JButton jbt2 = new JButton(usIcon);
18
19 JPanel p1 = new JPanel();
20 p1.add(jbt1);
21
22 JPanel p2 = new JPanel();
23 p2.add(jbt2);
24
25 JPanel p3 = new JPanel();
26 p2.add(jbt1);
27
28 add(p1, BorderLayout.NORTH);
29 add(p2, BorderLayout.SOUTH);
30 add(p3, BorderLayout.CENTER);
31 }
32 }

12.27 Can a border or an icon be shared by GUI components?

12.11 JButton
To create a push button, use the JButton class.

Key
Point

We have used JButton in the examples to demonstrate the basics of GUI programming. This
section will introduce more features of JButton . The following sections will introduce GUI
components JCheckBox , JRadioButton , JLabel , JTextField , and JPasswordField .
More GUI components such as JTextArea , JComboBox , JList , JScrollBar , and
JSlider will be introduced in Chapter 17. The relationship of these classes is pictured in
Figure 12.14.