Use Java Timer to move a panel smoothly, need help!

Question

I am using JBuilder to build an Windows Application.
I put everything on the contentPane. There is one Panel I call it "jPanelDemo" and another panel "jPanelText".
Now I want to start a timer, and move jPanelDemo panel from the right side of jPanelText to the same location of jPanelText, when the timer stops, jPanelDemo should place the jPanelText position.
Here is my code:
// declare the timer
  Timer timer1 = new Timer(1000,null);
  int timerSpeed = 1;
// here is the ActionListener
    timer1.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
       while (jPanelDemo.getLocation().x > jPanelText.getLocation().x)
         jPanelDemo.setLocation(jPanelDemo.getLocation().x - timerSpeed, jPanelDemo.getLocation().y);
         contentPane.repaint();
         jPanelDemo.repaint();
       timer1.stop();
// here to ensure jPanelDemo replaced jPanelText
jPanelDemo.setLocation(jPanelText.getLocation().x, jPanelDemo.getLocation().y);
   );The timer is triggered by clicking a certain Jbutton.
I did the similar codeing in .NET programming and it worked fine. However, I translate the code to Java. When I run this code, the timer actually works, and jPanelDemo does move and replace the jPanelText.
The problem I am facing now is: when I start the timer, the movement of jPanelDemo cannot be seen, until the timer stopped, the jPanelDemo poped up at the same location of jPanelText.
I tried to use contentPane.repaint(), it doesn't work for me.
Please help me solve this problem.

Answer 1

I do not quite understand what you mean.
I added the ActionListener when I initialize the
controls while the frame is loaded.Yes I missed that but you still have a loop in the event thread which is a NO NO. Maybe this will illustrate AN approach -
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Fred702 extends JPanel
    public Fred702()
        super(null);
        setPreferredSize(new Dimension(640, 480));
        final JLabel label = new JLabel("Hello");
        add(label);
        final int deltaT = 50;
        new javax.swing.Timer(deltaT, new ActionListener()
            double theta = 0.0;
            double deltaTheta = 0.2 * Math.PI * deltaT / 1000.0;
            int r = 200;
            public void actionPerformed(ActionEvent e)
                int x = (int)(Math.sin(theta) * r + 0.5 + r);
                int y = (int)(Math.cos(theta) * r + 0.5 + r);
                label.setBounds(x, y, label.getPreferredSize().width, label.getPreferredSize().height);
                theta += deltaTheta;
        }).start();
    public static void main(String[] args)
        JFrame frame = new JFrame("Fred702");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new Fred702());
        frame.pack();
        frame.setVisible(true);
}