multiballworld.java

一些JAVA的小程序

//
//	Multiple Ball version of the Ball World Game
//	Described in Chapter 5 of
//	Understanding Object-Oriented Programming with Java
//	by Timothy A Budd
//	Published by Addison-Wesley
//
//	see ftp://ftp.cs.orst.edu/pub/budd/java/ReadMe.html
//	for further information
//

import java.awt.*;
import java.awt.event.*;


public class MultiBallWorld extends Frame {

	public static void main (String [ ] args)
	{
		MultiBallWorld world = new MultiBallWorld (Color.red);
		world.show ();
	}

	private static final int FrameWidth = 600;
	private static final int FrameHeight = 400;
	private Ball [ ] ballArray;
	private static final int BallArraySize = 6;
	private int counter = 0;

	private MultiBallWorld (Color ballColor) {
		// constructor for new ball world
			// resize our frame
		setSize (FrameWidth, FrameHeight);
		setTitle ("Ball World");

			// initialize object data field
		ballArray = new Ball [ BallArraySize ];
		for (int i = 0; i < BallArraySize; i++) {
			ballArray[i] = new Ball(10, 15, 5);
			ballArray[i].setColor (ballColor);
			ballArray[i].setMotion (3.0+i, 6.0-i);
			}
	}

	public void paint (Graphics g) {
		for (int i = 0; i < BallArraySize; i++) {
			ballArray[i].paint (g);
				// then move it slightly
			ballArray[i].move();
			if ((ballArray[i].x() < 0) || (ballArray[i].x() > FrameWidth))
				ballArray[i].setMotion (-ballArray[i].xMotion(), ballArray[i].yMotion());
			if ((ballArray[i].y() < 0) || (ballArray[i].y() > FrameHeight))
				ballArray[i].setMotion (ballArray[i].xMotion(), -ballArray[i].yMotion());
			}
				// finally, redraw the frame
		counter = counter + 1;
		if (counter < 2000) repaint();
		else System.exit(0);
	}
}