multiballworldpanel.java

一些JAVA的小程序

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

public class MultiBallWorldPanel extends JPanel {

	public MultiBallWorldPanel (Color ballColor) {
		for (int i = 0; i < BallCollectionSize; i++) {
			balls[i] = new Ball(new Point(10, 15), 5);
			balls[i].setColor(ballColor);
			balls[i].setMotion(3.0+i, 6.0-i);
		}

	}

	private static final int BallCollectionSize = 10;
	private Ball [ ] balls = new Ball [ BallCollectionSize ];
	
	public void paint (Graphics g) {
		super.paint(g);
		for (int i = 0; i < BallCollectionSize; i++)
			balls[i].paint(g);
	}

	public void moveBall(int width, int height) {
		for (int i = 0; i < BallCollectionSize; i++) {
			Ball aBall = balls[i];
			aBall.move();
			int r = aBall.radius();
			if ((aBall.x() < r) || (aBall.x() > width - r))
				aBall.reflectHorz();
			if ((aBall.y() < r) || (aBall.y() > height - r))
				aBall.reflectVert();
		}
	}
}