Hi friend,


import java.awt.*;
import java.util.*;

public class Ball {

float x, y;
float radius;
float speed;
float moveAngle;
private Color color;

// Constructor
public Ball(float x, float y, float radius, float speed, float angleInDegree, Color color) {
this.x = x;
this.y = y;
this.speed = speed;
this.moveAngle = (float)Math.toRadians(angleInDegree);
this.radius = radius;
this.color = color;
}

public float getSpeedX() {
return speed * (float)Math.cos(moveAngle);
}

public float getSpeedY() {
return speed * (float)Math.sin(moveAngle);
}

// Update the position of the ball (move one step).
public void update() {
x += getSpeedX();
y += getSpeedY();
}

// Draw itself
public void draw(Graphics g) {
g.setColor(color);
g.fillOval((int)(x - radius), (int)(y - radius), (int)(2 * radius), (int)(2 * radius));
}

// For debugging.
public String toString() {
StringBuilder sb = new StringBuilder();
Formatter formatter = new Formatter(sb);
formatter.format("(%3.0f,%3.0f) V=%5.2f \u0398=%8.3f",
x, y, speed, Math.toDegrees(moveAngle));
return sb.toString();
}
}

import java.awt.*;
import java.util.Random;
import javax.swing.*;

public class BallWorld extends JFrame {

private static final int BOX_WIDTH = 640;
private static final int BOX_HEIGHT = 480;
private static final int UPDATE_RATE = 30;
private static final long UPDATE_PERIOD = 1000L / UPDATE_RATE;

private Ball ball;
// Handle for the custom drawing panel
private GameCanvas box;

// Constructor to create the UI components and init the game objects
public BallWorld() {
// UI components
box = new GameCanvas();
box.setPreferredSize(new Dimension(BOX_WIDTH, BOX_HEIGHT));
this.setContentPane(box);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.pack();
this.setTitle("Bouncing Ball");
this.setVisible(true);

// Start the game
gameStart();
}

// Start the ball bouncing
public void gameStart() {
// Generate a ball at a random location and moveAngle.
int radius = 200;
Random rand = new Random();
int x = rand.nextInt(BOX_WIDTH - radius * 2) + radius;
int y = rand.nextInt(BOX_HEIGHT - radius * 2) + radius;
int speed = 5;
int angleInDegree = rand.nextInt(360) - 179;
ball = new Ball(x, y, radius, speed, angleInDegree, Color.pink);
Thread gameThread = new Thread() {
public void run() {
while (true) {
gameUpdate();
repaint();

try {
Thread.sleep(UPDATE_PERIOD);
} catch (InterruptedException ex) { }
}
}
};
gameThread.start();
}

// Update the game objects and states
public void gameUpdate() {
// Compute the new position
ball.update();
// Detect collision and provide response
box.collidedWith(ball);
}

class GameCanvas extends JPanel {

public void paintComponent(Graphics g) {
super.paintComponent(g);
setBackground(Color.BLACK);
ball.draw(g);
// Display ball info for debugging.
g.setColor(Color.WHITE);
g.setFont(new Font("Courier New", Font.PLAIN, 12));
g.drawString("Ball: " + ball, 10, 20);
}

// Detect collision with the given ball, and provide response.
public boolean collidedWith(Ball ball) {
float currX = ball.x;
float currY = ball.y;
float radius = ball.radius;

if (currX + radius < BOX_WIDTH && currX - radius >= 0
&& currY + radius < BOX_HEIGHT && currY - radius >= 0) {
return false;
}

// collision
synchronized (ball) {
float prevX = currX - ball.getSpeedX();
float prevY = currY - ball.getSpeedY();
float angle = ball.moveAngle;
float angleTangent = (float)Math.tan(angle);
float newX, newY;

if (currX + radius >= BOX_WIDTH) {
newX = BOX_WIDTH - 1 - radius;
newY = angleTangent * (newX - prevX) + prevY;
ball.x = newX;
ball.y = newY;
// Keep the angle within -pi to pi (not necessary)
if (angle >= 0) {
ball.moveAngle = (float)Math.PI - angle;
} else {
ball.moveAngle = -(float)Math.PI - angle;
}
} else if (currX - radius < 0) {
newX = radius;
newY = angleTangent * (newX - prevX) + prevY;
ball.x = newX;
ball.y = newY;
// Keep the angle within -pi to pi (not necessary)
if (angle >= 0) {
ball.moveAngle = (float)Math.PI - angle;
} else {
ball.moveAngle = -(float)Math.PI - angle;
}
}
currX = ball.x;
currY = ball.y;
angle = ball.moveAngle;
if (currY + radius >= BOX_HEIGHT) {
newY = BOX_HEIGHT - 1 - radius;
newX = (newY - prevY) / angleTangent + prevX;
ball.x = newX;
ball.y = newY;
ball.moveAngle = -angle;
} else if (currY - radius < 0) {
newY = radius;
newX = (newY - prevY) / angleTangent + prevX;
ball.x = newX;
ball.y = newY;
ball.moveAngle = -angle;
}
}
return true;
}
}

public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
new BallWorld();
}
});
}
}

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visit for more information:

http://www.roseindia.net/java/example/java/swing/

Thanks.

Amardeep