New to java - glitch in my program/game? should be a simple fix :)

Question

hey everyone, I'm a student who's new to java programming :) It's is also the first programming language that I'm learning. I know the basics, but nothing very complicated.
I'm making a pong-like game, in an applet.
As I was making the paddle and using a mouselistener to make it move vertically, I came across this problem, the paddle will move vertically with the mouse's position, but one end of my paddle will grow abnormally (I want it to stay the same size as it moves up and down)
Here's my code: (I'm not using most of the mouselistener and keylistener classes yet, so you can ignore them. I'm guessing the problem is probably in one of the last classes, at the bottom)
ypaddle is the variable used for getting the co-ordinates of the mouse and transferring them to the paddle itself
// The "Ping" class.
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
*Ping
public class Ping extends Applet
    implements KeyListener, MouseListener, MouseMotionListener
    int width, height, x, ypaddle;
    Graphics g;
    char move;
     *Initializes variables
    public void init ()
        resize (700, 500);
        setBackground (Color.white);
        addKeyListener (this);
        addMouseListener (this);
        addMouseMotionListener(this);
    public void keyPressed (KeyEvent e)
    public void keyReleased (KeyEvent e)
    public void keyTyped (KeyEvent e)
    public void mouseEntered (MouseEvent e)
    public void mouseExited (MouseEvent e)
    public void mousePressed (MouseEvent e)
    public void mouseReleased (MouseEvent e)
    public void mouseClicked (MouseEvent e)
    public void mouseMoved (MouseEvent e)
        ypaddle = e.getY ();
        repaint();
    public void mouseDragged (MouseEvent e)
    public void paint (Graphics g)
        paddle (g, ypaddle);
     * Creates the paddle for hitting the ball
     *@param    y   value used to move the paddle vertically
    public void paddle (Graphics g, int y)
        g.fillRect (10, 10+y, 15, 60+y);
} // Ping classI'm totally stumped, I've tried for 2 hours to find the problem, and I have a feeling it's something very simple that I'm passing over...
If you have any questions about the variables or other things, please ask!
And one last little quick question, is there a way I can restrict the movement of the paddle between two Y values? (i.e not higher than y=10 or lower than y=100)
Thanks in advance :)

Answer 1

soundweave wrote:
I'm not exactly sure how to find out, Eh?
You wrote this code:
g.fillRect (10, 10+y, 15, 60+y);Do you understand what fillRect does? If I call fillRect(10, 20, 30, 40) where will that rectangle be drawn? If you don't know how to answer that, I don't see how you could have written that line of code.
but here's some pictures of what happens ( I put in 0 and 80 as the y values in each picture, and left the code window open so you can see )I don't need to see them.
Y at 0: [http://i731.photobucket.com/albums/ww314/len56/Untitled.jpg?t=1263077701|http://i731.photobucket.com/albums/ww314/len56/Untitled.jpg?t=1263077701]
Y at 80: [http://i731.photobucket.com/albums/ww314/len56/Untitled2.jpg?t=1263077625|http://i731.photobucket.com/albums/ww314/len56/Untitled2.jpg?t=1263077625]
So, given that the first one comes from fillRect(10, 10, 15, 60), (you get where that comes from I hope) and the second comes from fillRect(10, 90, 15, 150) (that too), does that not suggest that something is wrong with the numbers you're passing to fillRect? And since you have read the docs for fillRect and know what it does and what each of its parameters represents (right?), does it not suggest exactly what is wrong with those numbers?