Java Reference
In-Depth Information
4
import
java.awt.event.KeyListener;
5
import
java.awt.event.KeyEvent;
6
import
javax.swing.JFrame;
7
import
javax.swing.JTextArea;
8
9
implements
KeyListener
public
class
KeyDemoFrame
extends
JFrame
10
{
11
private final
String line1 =
""
;
// first line of text area
12
private final
String line2 =
""
;
// second line of text area
13
private final
String line3 =
""
;
// third line of text area
14
private final
JTextArea textArea;
// text area to display output
15
16
// KeyDemoFrame constructor
17
public
KeyDemoFrame()
18
{
19
super
(
"Demonstrating Keystroke Events"
);
20
21
textArea =
new
JTextArea(
10
,
15
);
// set up JTextArea
22
textArea.setText(
"Press any key on the keyboard..."
);
23
textArea.setEnabled(
false
);
24
textArea.setDisabledTextColor(
Color.BLACK
);
25
add(textArea);
// add text area to JFrame
26
27
addKeyListener(
this
);
// allow frame to process key events
28
}
29
30
// handle press of any key
31
@Override
32
public
void
keyPressed(KeyEvent event)
33
{
34
line1 = String.format(
"Key pressed: %s"
,
35
KeyEvent.getKeyText(event.getKeyCode())
);
// show pressed key
36
setLines2and3(event);
// set output lines two and three
37
}
38
39
// handle release of any key
40
@Override
41
public
void
keyReleased(KeyEvent event)
42
{
43
line1 = String.format(
"Key released: %s"
,
44
KeyEvent.getKeyText(event.getKeyCode())
);
// show released key
45
setLines2and3(event);
// set output lines two and three
46
}
47
48
// handle press of an action key
49
@Override
50
public
void
keyTyped(KeyEvent event)
51
{
52
line1 = String.format(
"Key typed: %s"
,
event.getKeyChar()
);
53
setLines2and3(event);
// set output lines two and three
54
}
55
Fig. 12.36
|
Key event handling. (Part 2 of 3.)
