canvasdemo6.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 canvasDemo6 extends MIDlet
{
   Display display;
   canvasClip canvasclip;

   public canvasDemo6()
   {
      canvasclip=new canvasClip();
      display=Display.getDisplay(this);
   }

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

   public void pauseApp(){}

   public void destroyApp(boolean unconditional){}

   class canvasClip extends Canvas 
   {
      int    gameaction=0;
      int    x=0;
      int    y=0;
      int    width;
      int    height;
      Image  pictureImage;
      Random viewRand;

      public canvasClip()
      {
         try{
             pictureImage=Image.createImage("/picture.png");
         }catch(Exception ex){}
      }
      
      public void keyPressed(int keyCode) 
      {
         gameaction=getGameAction(keyCode);
         viewRand=new Random();
         x=(int)Math.abs(viewRand.nextInt()%60);
         y=(int)Math.abs(viewRand.nextInt()%60);
         switch(gameaction)
         {
            case FIRE:
                 repaint();                 
                 break;
          }
      }

      public void paint(Graphics g)
      { 
         g.setColor(0xFFFFFF);
         g.fillRect(0,0,getWidth(),getHeight());
         g.setColor(0);
         g.setClip(30, 60, x, y);
         width=g.getClipWidth();
         height=g.getClipHeight();
         g.drawImage(pictureImage, 30, 60, Graphics.LEFT | Graphics.TOP);
         g.setClip(0, 0, getWidth(), getHeight());
         g.drawString("宽度:"+width, 50, 10, Graphics.HCENTER | Graphics.TOP);
         g.drawString("高度:"+height, 50, 30, Graphics.HCENTER | Graphics.TOP); 
         g.clipRect(100, 60, x, y);
         width=g.getClipWidth();
         height=g.getClipHeight();
         g.drawImage(pictureImage, 100, 60, Graphics.LEFT | Graphics.TOP);
         g.setClip(0, 0, getWidth(), getHeight());
         g.drawString("矩形宽度:"+width, 120, 10, Graphics.HCENTER | Graphics.TOP);
         g.drawString("矩形高度:"+height, 120, 30, Graphics.HCENTER | Graphics.TOP); 
         g.drawRect(100, 60, x, y);
      }
   }
}