Waiting for the user with Swing
I want the user to wait a certain amount of time (10 seconds). I know we are using META tag in JSPs or servlets <META HTTP-EQUIV="Refresh" CONTENT="3">
. Is there a way in Swing that we can make the user wait for a while. I am using Swing; I want the user to wait for a certain amount of time and I want to display some information to be fetched from the database. Is this possible through Swing?
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You can use javax.swing.Timer
. For example:
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class SimpleTimer extends JFrame implements ActionListener
{
private JLabel label;
private Timer timer;
private int counter = 10; // the duration
private int delay = 1000; // every 1 second
private static final long serialVersionUID = 1L;
public SimpleTimer()
{
super("Simple Timer");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(300, 65);
label = new JLabel("Wait for " + counter + " sec");
getContentPane().add(label);
timer = new Timer(delay, this);
timer.setInitialDelay(0);
timer.start();
setVisible(true);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
new SimpleTimer();
}
});
}
@Override
public void actionPerformed(ActionEvent e)
{
if(counter == 0)
{
timer.stop();
label.setText("The time is up!");
}
else
{
label.setText("Wait for " + counter + " sec");
counter--;
}
}
}
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Prior to WebSockets, HTTP servers could not dispatch events to HTTP clients; interactions were mostly request-response. Many applications are working on this problem using a polling (client-side) approach. The update meta tag is one way to implement a poll.
The swing is very different - you have the full force of the events. Thus, the idea of making the user wait for a certain amount of time is usually a wrong interaction. (Some play / poll / animation are some of the exceptions where just waiting makes sense.)
You must develop a Swing GUI that is functional and responsive until the results have been computed / retrieved. After the results are available, update the model and fire the event that changed the model.
The model itself can perform background calculations, polls, etc. as needed; this code doesn't depend on swing. If you would like to help with this aspect, consider finding out / asking about it separately on Stack Overflow.
Finally, remember that sleeping on a swinging thread will make the UI unresponsive. And on a related note, any event triggered by your model should be queued to the Swing event stream. See SwingUtilities.invokeLater (...) for how this is done.
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