Java Reference
In-Depth Information
This case study presents an applet that displays a nation's flag and plays its anthem.
Key
Point
The images in the applet are for seven national flags, named
flag0.gif
,
flag1.gif
, . . .,
flag6.gif
for Denmark, Germany, China, India, Norway, the U.K., and the U.S. They are stored under
the
image
directory in the class path. The audio consists of national anthems for these seven
nations, named
anthem0.mid
,
anthem1.mid
, . . ., and
anthem6.mid
. They are stored under
the
audio
directory in the class path.
The program enables the user to select a nation from a combo box and then displays its flag
and plays its anthem. The user can suspend the audio by clicking the
Suspend
button and
resume it by clicking the
Resume
button, as shown in Figure 18.15.
F
IGURE
18.15
The applet displays a sequence of images and plays audio.
The program is given in Listing 18.13.
L
ISTING
18.13
FlagAnthem.java
1
import
java.awt.*;
2
import
java.awt.event.*;
3
import
javax.swing.*;
4
import
java.applet.*;
5
6
public class
FlagAnthem
extends
JApplet {
7
VideoNote
Audio and image
private final static int
NUMBER_OF_NATIONS =
7
;
8
private int
current =
0
;
9
private
ImageIcon[] icons =
new
ImageIcon[NUMBER_OF_NATIONS];
image icons
audio clips
current audio clip
10
11
12
13
private
JLabel jlblImageLabel =
new
JLabel();
14
private
JButton jbtResume =
new
JButton(
"Resume"
);
15
private
JButton jbtSuspend =
new
JButton(
"Suspend"
);
16
private
JComboBox jcboNations =
new
JComboBox(
new
Object[]
17 {
"Denmark"
,
"Germany"
,
"China"
,
"India"
,
"Norway"
,
"UK"
,
"US"
});
18
19
public
FlagAnthem() {
20
// Load image icons and audio clips
21
for
(
int
i =
0
; i < NUMBER_OF_NATIONS; i++) {
22 icons[i] =
new
ImageIcon(getClass().getResource(
23
private
AudioClip[] audioClips =
new
AudioClip[NUMBER_OF_NATIONS];
private
AudioClip currentAudioClip;
GUI components
create icons
"image/flag"
+ i +
".gif"
));
24
25
26 }
27
28 JPanel panel =
new
JPanel();
audioClips[i] = Applet.newAudioClip(
create audio clips
getClass().getResource(
"audio/anthem" + i + ".mid"
));
create UI
