Bola.java
package bola;
import javax.swing.JFrame;
/**
*
* @author Acer
*/
public class Bola {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
// Set up main window (using Swing's Jframe)
JFrame frame = new JFrame("A Bouncing Ball");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(new BouncingBallSimple());
frame.pack();
frame.setVisible(true);
}
});
}
}
BouncingBallSimple.java
package bola;
import java.awt.*;
import java.util.Formatter;
import javax.swing.*;
/**
* One ball bouncing inside a rectangular box.
* All codes in one file. Poor design!
*/
// Extends JPanel, so as to override the paintComponent() for custom rendering codes.
public class BouncingBallSimple extends JPanel {
// Container box's width and height
private static final int BOX_WIDTH = 640;
private static final int BOX_HEIGHT = 480;
// Ball's properties
private float ballRadius = 200; // Ball's radius
private float ballX = ballRadius + 50; // Ball's center (x, y)
private float ballY = ballRadius + 20;
private float ballSpeedX = 3; // Ball's speed for x and y
private float ballSpeedY = 2;
private static final int UPDATE_RATE = 30; // Number of refresh per second
/** Constructor to create the UI components and init game objects. */
public BouncingBallSimple() {
this.setPreferredSize(new Dimension(BOX_WIDTH, BOX_HEIGHT));
// Start the ball bouncing (in its own thread)
Thread gameThread = new Thread() {
public void run() {
while (true) { // Execute one update step
// Calculate the ball's new position
ballX += ballSpeedX;
ballY += ballSpeedY;
// Check if the ball moves over the bounds
// If so, adjust the position and speed.
if (ballX - ballRadius < 0) {
ballSpeedX = -ballSpeedX; // Reflect along normal
ballX = ballRadius; // Re-position the ball at the edge
} else if (ballX + ballRadius > BOX_WIDTH) {
ballSpeedX = -ballSpeedX;
ballX = BOX_WIDTH - ballRadius;
}
// May cross both x and y bounds
if (ballY - ballRadius < 0) {
ballSpeedY = -ballSpeedY;
ballY = ballRadius;
} else if (ballY + ballRadius > BOX_HEIGHT) {
ballSpeedY = -ballSpeedY;
ballY = BOX_HEIGHT - ballRadius;
}
// Refresh the display
repaint(); // Callback paintComponent()
// Delay for timing control and give other threads a chance
try {
Thread.sleep(1000 / UPDATE_RATE); // milliseconds
} catch (InterruptedException ex) { }
}
}
};
gameThread.start(); // Callback run()
}
/** Custom rendering codes for drawing the JPanel */
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g); // Paint background
// Draw the box
g.setColor(Color.BLACK);
g.fillRect(0, 0, BOX_WIDTH, BOX_HEIGHT);
// Draw the ball
g.setColor(Color.BLUE);
g.fillOval((int) (ballX - ballRadius), (int) (ballY - ballRadius),
(int)(2 * ballRadius), (int)(2 * ballRadius));
// Display the ball's information
g.setColor(Color.WHITE);
g.setFont(new Font("Courier New", Font.PLAIN, 12));
StringBuilder sb = new StringBuilder();
Formatter formatter = new Formatter(sb);
formatter.format("Ball @(%3.0f,%3.0f) Speed=(%2.0f,%2.0f)", ballX, ballY,
ballSpeedX, ballSpeedY);
g.drawString(sb.toString(), 20, 30);
}
/**
*
* @author Acer
*/
public class Frame extends javax.swing.JFrame {
/**
* Creates new form Frame
*/
public Frame() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 300, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
}
}
Tidak ada komentar:
Posting Komentar