clock.java

Java2游戏编程源码 第四章 很好的学习Java和简单游戏编程的书籍

// 程序：电子小时钟
// 范例文件：Clock.java

import java.awt.*;
import java.util.*;       
import java.applet.*;

public class Clock extends Applet implements Runnable
{

   int          hour,minute,second,ImageWidth,ImageHeight,X,Y,
                width,height;
   Image        digit[],Background,OffScreen;
   Thread       newThread;
   boolean      showSeparator;
   Graphics     drawOffScreen;
   MediaTracker MT;

   GregorianCalendar time; 

 
   public void init()
   {
      X      = 50;      
      Y      = 110;
      MT     = new MediaTracker(this); 
      digit  = new Image[11];
      width  = 210;  
      height = 135;


      Background = getImage(getDocumentBase(),"Images/clock.jpg");
      MT.addImage(Background,0);

      for(int i=0;i<11;i++)
      {
         digit[i] = getImage(getDocumentBase(),"Images/" + i + ".jpg");
         MT.addImage(digit[i],0);
      }

      try
      {
         showStatus("图像载入中(Loading Images)...");
         MT.waitForAll();
      }
      catch(InterruptedException E){ }


      ImageWidth  = digit[0].getWidth(this);
      ImageHeight = digit[0].getHeight(this);


      OffScreen     = createImage(300,300);
      drawOffScreen = OffScreen.getGraphics();

      showSeparator = true;
   }

   public void start()     
   {
      newThread = new Thread(this);  
      newThread.start();
   }

   public void stop()              
   {
      newThread = null;          
   }

   public void paint(Graphics g)
   {

      drawOffScreen.clearRect(X,Y,width,height);
     

      drawOffScreen.drawImage(Background,0,0,this);

      if(hour < 10)   
      {
         drawOffScreen.drawImage(digit[0],X,Y,this);
         drawOffScreen.drawImage(digit[hour],X+ImageWidth,Y,this);
      }
      else
      {
         drawOffScreen.drawImage(digit[hour/10],X,Y,this);
         drawOffScreen.drawImage(digit[hour%10],X+ImageWidth,Y,this);
      }

      if(minute < 10)
      {
          
         drawOffScreen.drawImage(digit[0],X+ImageWidth*2+10,Y,this);
         drawOffScreen.drawImage(digit[minute],X+ImageWidth*3+10,Y,this);
      }
      else
      {
         drawOffScreen.drawImage(digit[minute/10],X+ImageWidth*2+10,Y,this);
         drawOffScreen.drawImage(digit[minute%10],X+ImageWidth*3+10,Y,this);
      }

      if(second < 10)
      {
         drawOffScreen.drawImage(digit[0],X+ImageWidth*4+15,
                                 Y+ImageHeight-30,15,30,this);
         drawOffScreen.drawImage(digit[second],X+ImageWidth*4+30,
                                 Y+ImageHeight-30,15,30,this);
      }
      else
      {
         drawOffScreen.drawImage(digit[second/10],X+ImageWidth*4+15,
                                 Y+ImageHeight-30,15,30,this);
         drawOffScreen.drawImage(digit[second%10],X+ImageWidth*4+30,
                                 Y+ImageHeight-30,15,30,this);
      }     

      if(showSeparator) 
         drawOffScreen.drawImage(digit[10],X+ImageWidth*2,Y+10,this);

      g.drawImage(OffScreen,0,0,this);
   }

   public void update(Graphics g)    
   {
      paint(g);                      
   }

   public void run()
   {  
      while(newThread != null)       
      {  

         time   = new GregorianCalendar();


         hour   = time.get(Calendar.HOUR_OF_DAY);
         minute = time.get(Calendar.MINUTE);
         second = time.get(Calendar.SECOND);

         if(second % 2 == 0)      
            showSeparator = true;
         else
            showSeparator = false;
 
         repaint(X,Y,width,height); 

         try
         {
            Thread.sleep(500);      
         }
         catch(InterruptedException E){ }
      }
   }
}