the ball is not moved

[theeradetch sillapacharoein]

package about_theball;

import java.awt.Graphics;
import java.awt.Color;

public class Ball
{
public Vector pos,vel,acc;
public int R,G,B,Size;

public void move()
{
	vel = vel.add(acc);
	pos = pos.add(vel);
	
		if(pos.x<0)
		{
			pos.x=0;
		vel.x*=-1;
		
		}
		if (pos.y<0)
		{
			pos.y=0;
			vel.y*=-1;
			
		}
		if(pos.x>500)
		{
			pos.x=500;
			vel.x*=-1;
			
		}
		if(pos.y>500)
		{
			pos.y = 500;
			vel.y*=-1;
			
		}
	}


	public void draw(Graphics g)
	{
		g.setColor(new Color(R,G,B,190));
		g.fillOval((int)pos.x , (int)pos.y,Size, Size);
	}
}

package about_theball;

public class Vector
{
public double x,y;
public Vector() {}
public Vector(double xx,double yy)
{
	x=xx;
	y=yy;
	
}
public Vector add(Vector v)
{
	return new Vector(x+v.x,y+v.y);
	
}
}

package about_theball;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class GUI extends JPanel
{
Ball balls[];

public GUI() // this is Constructor
{
	balls = new Ball[10];
	for (int i =0;i<balls.length;i++)
	{
		balls[i] = new Ball();
		balls [i].pos = new Vector();
		balls [i].vel = new Vector();
		balls [i].acc = new Vector();
		balls [i].pos.x = (int) (Math.random()*500);
		balls [i].pos.y = (int) (Math.random()*500);
		
		balls [i].vel.x = (int) (Math.random()*10-5);
		balls [i].vel.y = (int) (Math.random()*10-5);
		
		
		balls [i].R = (int) (Math.random()*255);
		balls [i].G = (int) (Math.random()*255);
		balls [i].B = (int) (Math.random()*255);
		balls [i].Size = (int) (Math.random()*255);
	}
	JFrame f = new JFrame();
	f.add(this);
	f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
	f.setSize(500, 500);
	f.setVisible(true);
}
public void paint(Graphics g) 
{
super.paint(g);
for(int i =0;i<balls.length;i++)
{
	balls[i].draw(g);
	
}
}
public static void main(String[] args) {
	new GUI();
	
}
	
}

[Carey Brown]

Do you have a specific question you want help with?

[Carey Brown]

Sorry, missed your subject heading.

You are not calling move() anywhere, so it's not moving.

The best way to do this is to create a method that will move all the balls and then call repaint(). Then create a swing.Timer object that calls that method. Experiment with the delay that you pass to the Timer.

[Fred Kleinschmidt]

Also, do not override the paint() method. you should override paintComponent() instead, and the first statement in that method should be

super.paintComponent(g);

[theeradetch sillapacharoein]

Carey Brown wrote:Sorry, missed your subject heading.

You are not calling move() anywhere, so it's not moving.

The best way to do this is to create a method that will move all the balls and then call repaint(). Then create a swing.Timer object that calls that method. Experiment with the delay that you pass to the Timer.

Sorry about that,

I already created the method  but it not moved as attached file.

plese,see the code 

acctually, I just started with new lesson about  GUI and method. i copy this code from my book and so it not working as described

[Paul Clapham]

You got that code from a book!? What book was that?

And does your latest post mean that you included the advice that Carey Brown in your new version of your code? If not, then why not?

(Also, showing us a picture of some circles isn't really evidence that the circles aren't moving when your code runs. It's only evidence that the code can display the circles successfully.)

[theeradetch sillapacharoein]

Paul Clapham wrote:You got that code from a book!? What book was that?

And does your latest post mean that you included the advice that Carey Brown in your new version of your code? If not, then why not?

(Also, showing us a picture of some circles isn't really evidence that the circles aren't moving when your code runs. It's only evidence that the code can display the circles successfully.)

sorry about that,

I will try back to deep study in each code.

thank you for your recommended

[Paul Clapham]

No, seriously, if you really got that code from a book which claims to teach you Java, then it isn't a very good book. Don't deep-study that code because it isn't good. Instead, I would suggest getting a different book, or even just start with Oracle's Java tutorials.