the squares go beyond the panel. how do I fix this problem?

Square Rebound

For this lab, you'll build on the Dots.java and DotsPanel.java programs. Instead of drawing dots you will draw squares so add that change. Add animation using a Timer so that the squares all move when drawn. Make each square move at random speed (in x and y directions), and have the squares "bounce" appropriately off all four sides of the screen. HINTS: Create 2 arrays of size 1000 to hold random values between 1 and 10 for the X movements and Y movements. This will allow your rectangles to have independent movement speeds. You will need to create a ActionListener class similar to what is used in ReboundPanel class. Inside the Actionistener class you create you will want to reference the X and Y array indexes rather than the static moveX and moveY used in the ReboundPanel.

This is what I have so far.

Dots.java

import javax.swing.JFrame;

public class Dots

{

//-----------------------------------------------------------------

// Creates and displays the application frame.

//-----------------------------------------------------------------

public static void main(String[] args)

{

JFrame frame = new JFrame("Dots");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().add(new DotsPanel());

frame.pack();

frame.setVisible(true);

}

}

DotsPanel.java

import java.awt.Color;

import java.awt.Dimension;

import java.awt.Graphics;

import java.awt.Point;

import java.awt.Rectangle;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import java.security.SecureRandom;

import java.util.ArrayList;

import java.util.Random;

import javax.swing.JPanel;

import javax.swing.Timer;

public class DotsPanel extends JPanel {

private final int SIZE = 6; // radius of each dot

private ArrayList pointList;

AnimationListener am;

// -----------------------------------------------------------------

// Constructor: Sets up this panel to listen for mouse events.

// -----------------------------------------------------------------

public DotsPanel() {

pointList = new ArrayList();

addMouseListener(new DotsListener());

am = new AnimationListener();

am.timer.start();

setBackground(Color.black);

setPreferredSize(new Dimension(300, 200));

}

private void setColor(Color color) {

}

// -----------------------------------------------------------------

// Draws all of the dots stored in the list.

// -----------------------------------------------------------------

public void paint(Graphics page) {

super.paintComponent(page);

SecureRandom randomNum = new SecureRandom();

Color color = new Color(randomNum.nextInt(256), randomNum.nextInt(256),

randomNum.nextInt(256));

page.setColor(color);

for (Point spot : pointList)

page.fillRect(spot.x - SIZE, spot.y - SIZE, SIZE * 2, SIZE * 2);

page.drawString("Count: " + pointList.size(), 5, 15);

}

// *****************************************************************

// Represents the listener for Animation, based on timer

// *****************************************************************

private class AnimationListener implements ActionListener {

int xRand[];

int yRand[];

Random rand;

public AnimationListener() {

rand = new Random();

xRand = new int[1000];

yRand = new int[1000];

for (int i = 0; i < 1000; i++) {

xRand[i] = rand.nextInt(20) - 10;

yRand[i] = rand.nextInt(20) - 10;

}

}

private Timer timer = new Timer(60, this);

public void actionPerformed(ActionEvent event) {

Rectangle window = getBounds();

for (int i = 0; i < pointList.size(); i++) {

Point spot = pointList.get(i);

spot.x += xRand[i];

spot.y += yRand[i];

if (spot.x <= 0) {

xRand[i] = Math.abs(xRand[i]);

} else if (spot.x >= window.width - (SIZE*2)) {

xRand[i] = -Math.abs(xRand[i]);

}

if (spot.y <= 0) {

yRand[i] = Math.abs(yRand[i]);

} else if (spot.y >= window.height - (SIZE*2)) {

yRand[i] = -Math.abs(yRand[i]);

}

}

repaint();

}

}

// *****************************************************************

// Represents the listener for mouse events.

// *****************************************************************

private class DotsListener implements MouseListener {

// --------------------------------------------------------------

// Adds the current point to the list of points and redraws

// the panel whenever the mouse button is pressed.

// --------------------------------------------------------------

public void mousePressed(MouseEvent event) {

pointList.add(event.getPoint());

repaint();

}

// --------------------------------------------------------------

// Provide empty definitions for unused event methods.

// --------------------------------------------------------------

public void mouseClicked(MouseEvent event) {}

public void mouseReleased(MouseEvent event) {}

public void mouseEntered(MouseEvent event) {}

public void mouseExited(MouseEvent event) {}

}

}