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Tips ‘n’ Tricks |
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3. Creating Indeterminate Progress
Bar in Java:
Sometimes, at the time of downloading
or transferring a file, we see a component
showing how much the particular task has
been completed. For this purpose, Java
provides a Progress Bar component to convey
the progress of completing a task in a GUI.
One way of showing this progress is in
percent format. But suppose a situation
where extent of the task is unknown and so
we are not able to present it in percent
format. To handle this situation java provides
a solution by putting the progress bar in
indeterminate mode. An indeterminate
progress bar animates constantly. By default,
every progress bar is determinate. You may
make any JProgressBar indeterminate pass
a “true” boolean value to etIndeterminate()
method. Just have a look on the code below:
IndeterminatePB.java:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class IndeterminatePB extends
JFrame {
JProgressBar ipb;
int number = 0;
public IndeterminatePB() {
super(“Indeterminate
Progress Bar
Example”);
setDefaultCloseOperation
(JFrame.EXIT_ON_CLOSE);
JPanel pane = new JPanel();
ipb = new
JProgressBar(JProgressBar.HORIZONTAL,
0,
1000);
//make any JProgressBar indeterminate |
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passing a true boolean value to
setIndeterminate() method.
ipb.setIndeterminate(true);
pane.add(ipb);
setContentPane(pane);
}
public void iterate() {
while (number <= 1000) {
ipb.setValue(number);
//Sets the progress bar’s current value to n.
try {
Thread.sleep(10);
}
catch (InterruptedException e) { }
number++;
}
//To stop the animation make the progress
bar determinate.
ipb.setIndeterminate(false);
}
public static void main(String[] args) {
IndeterminatePB frame = new
IndeterminatePB();
frame.pack();
frame.setVisible(true);
frame.iterate();
}
}
Compile and Run:
C:\JavaJazzup>javac IndeterminatePB.java
C:\JavaJazzup>java IndeterminatePB
Output:
The output below appears until the
completion of the task. The dark portion
waves from one side to the other.
When the task ends, progress bar appears like this.
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Sept 2007 | Java Jazz Up | 68 |
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