这是一个精灵类，请把它们注释，特别是翻转那儿不太懂
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
public class sprite extends MIDlet {
private Display dis;
mygame mg=new mygame();
Thread th=new Thread(mg);
public sprite() {
dis=Display.getDisplay(this);
dis.setCurrent(mg);
th.start();
}
protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
}
protected void pauseApp() {
// TODO Auto-generated method stub
}
protected void startApp() throws MIDletStateChangeException {
// TODO Auto-generated method stub
}
class mygame extends GameCanvas implements Runnable
{ private Image imgnpc;
private Image imgbeijing;
private Sprite npc;
private int n1=12;//up
private int n2=0;//down
private int n3=4;//left
private int n4=8;//right
private Graphics gr=this.getGraphics();
public mygame()
{super(true);
try{
imgnpc=Image.createImage("/npc.PNG");
imgbeijing=Image.createImage("/beijing.png");
}catch(Exception e){e.printStackTrace();}
npc=new Sprite(imgnpc,imgnpc.getWidth()/4,imgnpc.getHeight()/4);
npc.setPosition(50,50);
}
public void up()
{
if(n1==12)
{npc.move(0,-5);
npc.setFrame(13);
n1=13;}
else if(n1==13)
{npc.move(0,-5);
npc.setFrame(14);
n1=14;}
else if(n1==14)
{ npc.move(0,-5);
npc.setFrame(15);
n1=15;}
else if(n1==15)
{ npc.move(0,-5);
npc.setFrame(12);
n1=12;
}
}
public void down()
{
if(n2==0)
{ npc.move(0,5);
npc.setFrame(1);
n2=1;}
else if(n2==1)
{npc.move(0,5);
npc.setFrame(2);
n2=2;}
else if(n2==2)
{ npc.move(0,5);
npc.setFrame(3);
n2=3;}
else if(n2==3)
{npc.move(0,5);
npc.setFrame(0);
n2=0;
}
}
public void left()
{
if(n3==4)
{npc.setFrame(5);
npc.move(-5,0);
n3=5;}
else if(n3==5)
{npc.move(-5,0);
npc.setFrame(6);
n3=6;}
else if(n3==6)
{npc.setFrame(7);
npc.move(-5,0);
n3=7;}
else if(n3==7)
{npc.move(-5,0);
npc.setFrame(4);
n3=4;
}
}
public void right()
{
if(n4==8)
{npc.move(5,0);
npc.setFrame(9);
n4=9;}
else if(n4==9)
{npc.move(5,0);
npc.setFrame(10);
n4=10;}
else if(n4==10)
{npc.move(5,0);
npc.setFrame(11);
n4=11;}
else if(n4==11)
{npc.move(5,0);
npc.setFrame(8);
n4=8;
}
}
public void add()
{
gr.setColor(255,255,255);
gr.fillRect(0,0,getWidth(),getHeight());
gr.drawImage(imgbeijing,0,0,Graphics.LEFT|Graphics.TOP);
npc.paint(gr);
}
public void Action()
{int action=getKeyStates();
if((action & UP_PRESSED)!=0)
{ up();
}
if((action & DOWN_PRESSED)!=0)
{down();
}
if((action & LEFT_PRESSED)!=0)
{left();
}
if((action & RIGHT_PRESSED)!=0)
{ right();
}
check();
this.flushGraphics();
}
public void run()
{ while(true)
{add();
Action();
try{
Thread.sleep(66);
}catch(Exception ex){}
}
}
public void check()
{if(npc.getX()<=0)
{npc.move(5,0);}
if(npc.getX()>=getWidth()-npc.getWidth())
{npc.move(-5,0);}
if(npc.getY()<=0)
{npc.move(0,5);}
if(npc.getY()>=getHeight()-npc.getHeight())
{npc.move(0,-5);}
}
}
}