marble.java

来自「java编程开发技巧与实例的编译测试通过的所有例程」· Java 代码 · 共 57 行

import java.awt.*;

public class Marble extends Thread
{
	private int xdir	=	2 * (1 - 2 * (int)Math.round(Math.random()));
	private int ydir	=	2 * (1 - 2 * (int)Math.round(Math.random()));
	private boolean running = false;
	private Table table = null;
	protected int x, y;
	public Marble(Table _table, int _x, int _y)
	{
		table = _table;
		x = _x;
		y = _y;
		start();
	}
	public void start()
	{
		running = true;
		super.start();
	}
	public void halt()
	{
		running = false;
	}
	public void run()
	{
		while (running)
		{
			move();
			try
			{
				sleep(40);
			}
			catch	(InterruptedException ie)
			{
				System.err.println("Thread interrupted");
			}
			table.repaint();
		}
	}
	public void move()
	{
		x += xdir;
		y += ydir;
		if ((x > table.getSize().width) || (x < 0))
			xdir *= (- 1);
		if ((y > table.getSize().width) || (y < 0))
			ydir *= (- 1);
	}
	public void draw (Graphics g)
	{
		g.setColor(Color.cyan);
		g.fillOval(x, y, 20, 20);
	}
}