game.java

此游戏仅是用来使Java初学者掌握Java基础语法和面向对象的编程思想。

/**
 *声明：1、本程序是作为金鹰教育网学习Java基本语法的例子。可以自由使用，但必须保留此声明！
 *      2、具体的介绍、说明文档，请见金鹰教育网：www.eagledu.org
 *	    3、有问题的，请到金鹰教育网：www.eagledu.org中的Java标准版本课程中提出，我们会及时给予答复！
 *      4、有其它想法的，也可直接交流：[e-mail]
 */


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

public class Game extends Applet implements Runnable{

	private int xpos=100,ypos=0;//当前活动图形的相对坐标
	private BaseShape currShape;//当前活动的图形
	
	private Image buffer;//双缓存内存图
    private Graphics bg;
    
    private Thread th;
    private Button btnStart=new Button("开始");
    
    public Game()
    {
    	th=new Thread(this);
    }

	public void init() {
		
		buffer=this.createImage(200,400);
		bg=buffer.getGraphics();
				
		currShape=new Ding();
		currShape.setShape(xpos,ypos);

		bg.setColor(Color.BLACK);
		bg.fillRect(0,0,200,400);
		currShape.paint(bg);

		this.addKeyListener(new GameKeyLister());
		
		this.setLayout(null);
		btnStart.setBounds(220,20,60,20);
		btnStart.addActionListener(new StartActionListener());
		this.add(btnStart);
	}
	
	public void update(Graphics g)
	{
		g.clipRect(0,0,200,400);
		
		bg.setColor(Color.BLACK);
		bg.fillRect(0,0,200,400);
		currShape.paint(bg);
		
		paint(g);
	}
	
	public void paint(Graphics g) {

	   g.drawImage(buffer,0,0,this);
	}
	
	//子线程的代码，每隔0.5移，下移一格
	public void run()
	{
		while(true)
		{
			ypos+=20;
			currShape.setShape(xpos,ypos);
			
			if(currShape.getBottom()>400)
			{
				ypos-=20;
				currShape.setShape(xpos,ypos);										
			}
		
			repaint();
			try{
				
				Thread.sleep(500);				
			}
			catch(InterruptedException e)
			{	}
		}
		
	}
		
	//内部类，处理按钮单击事件
	class StartActionListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			th.start();
			
			requestFocus(true);//让applet得到焦点
	    }		
	}
	
	//内部类，以实现键盘的事件处理
	class GameKeyLister extends KeyAdapter
	{
		public void keyReleased(KeyEvent e)
		{
			int keyCode=e.getKeyCode();
			
			if(keyCode==KeyEvent.VK_UP)
			{
				currShape.rotate();
				currShape.setShape(xpos,ypos);
				
				while(currShape.getLeft()<0)
				{
					xpos+=20;
					currShape.setShape(xpos,ypos);
				}
				while(currShape.getRight()>200)
				{
					xpos-=20;
					currShape.setShape(xpos,ypos);					
				}
				while(currShape.getBottom()>400)
				{
					ypos-=20;
					currShape.setShape(xpos,ypos);										
				}
				
				repaint();
			}
			else if(keyCode==KeyEvent.VK_RIGHT && currShape.getRight()<200)
			{
				xpos+=20;
				currShape.setShape(xpos,ypos);
				
				repaint();
			}
			else if(keyCode==KeyEvent.VK_LEFT && currShape.getLeft()>0)
			{
				xpos-=20;
				currShape.setShape(xpos,ypos);
				
				repaint();
			}
			else if(keyCode==KeyEvent.VK_DOWN && currShape.getBottom()<400)
			{
				ypos+=20;
				currShape.setShape(xpos,ypos);
				
				repaint();
			}
		}
	}	
}