randomdemo.java

一本介绍手机游戏开发的书中的源代码

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.util.Random;

public class randomDemo extends MIDlet
{
   Display display;
   canvasRand canvasrand;

   public randomDemo()
   {
      canvasrand=new canvasRand();
      display=Display.getDisplay(this);
   }

   public void startApp()
   {
      display.setCurrent(canvasrand);
   }

   public void pauseApp(){}

   public void destroyApp(boolean unconditional){}

   class canvasRand extends Canvas 
   {
      int     gameaction;
      long    numlong1; 
      long    numlong2;
      long    numlong3;
      long    numlong4;
      Random  rand;
      Random  randseed; 

      public canvasRand(){}
      
      public void keyPressed(int keyCode) 
      {
         gameaction=getGameAction(keyCode);
         switch(gameaction)
         {
            case FIRE: 
                 rand=new Random();
                 randseed=new Random(10879);
                 numlong1=rand.nextInt();
                 numlong2=rand.nextLong();
                 numlong3=randseed.nextInt();
                 numlong4=randseed.nextLong();         
                 repaint();             
                 break;
          }
      }

      public void paint(Graphics g)
      { 
         g.setColor(0xFFFFFF);
         g.fillRect(0,0,getWidth(),getHeight());
         g.setColor(0);
         g.drawString("J2ME随机数表应用", getWidth()/2, 10, Graphics.HCENTER | Graphics.TOP);
         g.drawString("Random() nextInt:", 20, 30, Graphics.LEFT | Graphics.TOP);
         g.drawString(String.valueOf(numlong1), 30, 45, Graphics.LEFT | Graphics.TOP);
         g.drawString("Random() nextLong:", 20, 60, Graphics.LEFT | Graphics.TOP);
         g.drawString(String.valueOf(numlong2), 30, 75, Graphics.LEFT | Graphics.TOP);
         g.drawString("Random(seed) nextInt:", 20, 90, Graphics.LEFT | Graphics.TOP);
         g.drawString(String.valueOf(numlong3), 30, 105, Graphics.LEFT | Graphics.TOP);
         g.drawString("Random(seed) nextLong:", 20, 120, Graphics.LEFT | Graphics.TOP);
         g.drawString(String.valueOf(numlong4), 30, 135, Graphics.LEFT | Graphics.TOP);
      }
   }
}