Java Reference
In-Depth Information
Display 19.2
Threaded Version of
FillDemo
(part 2 of 3)
17
private
JPanel box;
18
public static void
main(String[] args)
19
{
20
ThreadedFillDemo gui =
new
ThreadedFillDemo();
21
gui.setVisible(
true
);
22
}
23
public
ThreadedFillDemo()
24
{
25
setSize(WIDTH, HEIGHT);
26
setTitle("Threaded Fill Demo");
27
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
28
setLayout(
new
BorderLayout());
29
box =
new
JPanel();
30
add(box, "Center");
31
JPanel buttonPanel =
new
JPanel();
32
buttonPanel.setLayout(
new
FlowLayout());
33
JButton startButton =
new
JButton("Start");
34
startButton.addActionListener(
this
);
35
buttonPanel.add(startButton);
36
add(buttonPanel, "South");
You need a thread object, even if
there are no instance variables in
the class definition of
Packer
.
37
}
38
public
void
actionPerformed(ActionEvent e)
39
{
40
Packer packerThread =
new
Packer();
41
packerThread.start();
42
}
start
“starts” the thread and calls
run
.
43
private class Packer
extends
Thread
run
is inherited from
Thread
but needs to be
overridden. This definition of
run
is identical
to that of
fill
in Display 19.1.
44
{
45
public
void
run()
46
{
47
Graphics g = box.getGraphics();
48
for
(
int
y = 0; y < FILL_HEIGHT; y = y + CIRCLE_SIZE)
49
for
(
int
x = 0; x < FILL_WIDTH; x = x + CIRCLE_SIZE)
50
{
51
g.fillOval(x, y, CIRCLE_SIZE, CIRCLE_SIZE);
52
doNothing(PAUSE);
53
}
54
}
