To make moving ball

I'm trying to make moving ball animation in Swing, but I don't know how. Can anybody help with this? I was reading about threads, but I didn't understand a lots of it...

If you just need to make animation for moving ball, then you don't need to use mutithreading. You can achieve this just using repaint method.
You just need to decide path for Ball, and keep repainting the ball.

I wrote this:

but I got just line of drawn balls. How to fix that? I would like to make more balls moving in line order one behind the other.

You have to keep logic such that only X and Y coordinates will get change every time you re paint it.
g.fillOval(130, i, 20, 20);

Can you explain me that little bit more detailed, please?

Don't ever call repaint() from paintComponent or paint - it will cause the method to call itself and your CPU usage goes up like a nutter.

Instead, check out javax.swing.Timer - you'll want to regularly cause a repaint with new coordinates, and the Timer will do the firing for you.

Hi, guys! I have been dealing with this problem and wrote this code:

package org.me.log;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class LogPanel2 extends JPanel {
    int i;
    int counter = 1;

// timer delay: equivalent to the Thread.sleep time
  private static final int TIMER_DELAY = 1;

// how far to move in x dimension with each loop of timer
     int DELTA_X = 1;

// the images x & y locations
  private int x2 = 130;
  private int y2 = 330;
  private int y21 = y2-50;
  private int y22=y2-100;
  private int y23=y2-150;
  private int y24=y2-200;

public LogPanel2() {
    try {
    } catch (Exception e) {
      e.printStackTrace();
    }

// create and start the Swing Timer
    new Timer(TIMER_DELAY, new TimerListener()).start();
  }

// all paintComponent does is paint -- nothing else
  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    g.setColor(Color.black);
    g.drawString("1", 42, 20);
    g.drawString("2", 137, 20);
    g.drawString("3", 232, 20);
    g.setColor(new Color (178, 34, 34));

g.fillOval(30, 50, 30, 30);
    g.fillOval(125, 55, 30, 30);
    g.fillOval(220, 50, 30, 30);

setBackground (Color.white);
    g.setColor(new Color (220,220,220));

g.fillRect(130,100,20,250);
    g.setColor(new Color (205,92,92));
       if (y2 <= 330 && y2 >= 85) {
            g.fillOval( x2, y2, 20, 20);
            g.fillOval( x2, y21, 20,20);
            g.fillOval( x2, y22, 20,20);
            g.fillOval( x2, y23, 20,20);
            g.fillOval( x2, y24, 20,20);

}
        }
  private class TimerListener implements ActionListener {
    // is called every TIMER_DELAY ms
    public void actionPerformed(ActionEvent e) {
            y2 -= DELTA_X;
            y21 -= DELTA_X;
            y22 -= DELTA_X;
            y23 -= DELTA_X;
            y24 -= DELTA_X;

if (y2<80){
          y2=330;
       }
           if (y21<80){
          y21=330;
      }
             if (y22<80){
          y22=330;
      }
                 if (y23<80){
          y23=330;
      }
                     if (y24<80){
          y24=330;
      }
            if (y2>=330){
                counter++;
            }

// ask JVM to paint this JPanel
      LogPanel2.this.repaint();
    }
  }

// call Swing code in a thread-safe manner
  public static void main(String[] args) {
    java.awt.EventQueue.invokeLater(new Runnable() {
      public void run() {
      }
    });
  }

}

This is code just for JPanel on which is my work drawn and it is then called from the JApplet. I would like to make 3 balls (from 5 of them) to get in horizontal line and to wait a moment simulating people waiting on 3 information desks. I hope I didn't explain too confusing

P.S. If you thing that I should make new topic for that problem, just say and I'll do it

maja neskovic wrote:
// call Swing code in a thread-safe manner public static void main(String[] args) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { } }); }

Huh?

What?

That code isn't doing much.

Yes, I saw when I removed it

And what about my question - about making 3 balls to stop in line and to wait a little bit? Any idea...?

What books do you have access to? There is an example in Horstmann and Cornell (I have the 6th edition myself and it is in the 1st chapter in vol II), which sounds quite like what you are doing.
I would have thought the other books would have similar examples, so try your library.

I have only Java in 21 days, but there is nothing about my problems... Would you be kind to send me that book on email?

That wouldn't be legal, so no.

Don't like the Java in 21 days book or similar, myself.

And I won't send my book by snail-mail, because I wish to keep it