canvasdemo2.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.*;

public class canvasDemo2 extends MIDlet
{
   Display display;
   canvasAnchor canvasanchor;

   public canvasDemo2()
   {
      canvasanchor=new canvasAnchor();
      display=Display.getDisplay(this);
   }

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

   public void pauseApp(){}

   public void destroyApp(boolean unconditional){}

   class canvasAnchor extends Canvas 
   {
      int     gameaction=0;
      int     moveX=0;
      int     moveY=0;
      int[]   moveLR={Graphics.RIGHT, Graphics.HCENTER, Graphics.LEFT};
      int[]   moveUD={Graphics.BOTTOM, Graphics.VCENTER, Graphics.TOP};
      String[] anchorLR={"Graphics.RIGHT", "Graphics.HCENTER", "Graphics.LEFT"};
      String[] anchorUD={"Graphics.BOTTOM", "Graphics.VCENTER", "Graphics.TOP"};
      Image   pictureImage;

      public canvasAnchor()
      {
         try{
             pictureImage=Image.createImage("/picture.png");
         }catch(Exception ex){} 
      }
      
      public void keyPressed(int keyCode) 
      {
         gameaction=getGameAction(keyCode);
         switch(gameaction)
         {
            case LEFT:
                 moveX--;
                 if(moveX<0) moveX=0;
                 repaint();
                 break;
            case RIGHT: 
                 moveX++;
                 if(moveX>2) moveX=2;
                 repaint();
                 break; 
            case UP:
                 moveY--;
                 if(moveY<0) moveY=0;
                 repaint();                
                 break;
            case DOWN:    
                 moveY++;
                 if(moveY>2) moveY=2;
                 repaint();            
                 break;
         }
      }

      public void paint(Graphics g)
      { 
         g.setColor(0xFFFFFF);
         g.fillRect(0, 0, getWidth(), getHeight());
         g.setColor(0);
         g.drawString("游戏图片的锚点", getWidth()/2, 2, Graphics.HCENTER | Graphics.TOP);
         g.drawString("状态:"+anchorLR[moveX]+" 左右数值:"+String.valueOf(moveLR[moveX]), 0, 22, Graphics.LEFT | Graphics.TOP);
         g.drawString("状态:"+anchorUD[moveY]+" 上下数值:"+String.valueOf(moveUD[moveY]), 0, 42, Graphics.LEFT | Graphics.TOP);
         g.drawImage(pictureImage, getWidth()/2, 117, moveLR[moveX] | moveUD[moveY]);
         g.drawLine(0,117,getWidth(),117);
         g.drawLine(getWidth()/2,57,getWidth()/2,177);
      }
   }
}