J2ME RPG游戏开发 精怪帧序列

J2ME RPG游戏开发 精灵帧序列
最近开发一款手机游戏  调用精灵的nextframe方法却只能循环到第二帧 请大家帮忙看下 谢啦

  

public class Game extends GameCanvas implements Runnable{
	private Sprite s,p;
	
	private LayerManager lm;
	private Image imgbg;
	private Image imgp;
	private int px,py;
	public Graphics offg;
	public int[] FRAME_SEQUENCE_DOWN={0, 1, 2, 3};
	public int[] FRAME_SEQUENCE_UP={12,13,14,15};
	public int[] FRAME_SEQUENCE_LEFT={4, 5, 6, 7};
	public int[] FRAME_SEQUENCE_RIGHT={8,9,10,11 };

	public Game() {
		super(true);
		px=12;
		py=23;
		lm=new LayerManager();
		try {
			imgbg=Image.createImage("/bg.png");
			imgp=Image.createImage("/frames.png");
		} catch (IOException e) {}	
		s=new Sprite(imgbg);
		p=new Sprite(imgp,24,36);
		
		lm.append(p);
		lm.append(s);
		lm.setViewWindow(0, 0, getWidth(), getHeight());
		offg=this.getGraphics();
		(new Thread(this)).start();
	}
	public void run() {
		while(true){
			input();
			
			offg.setColor(255);
			offg.fillRect(0,0,getWidth(),getHeight());
			lm.paint(offg,0, 0);
			
			paint();
			 try {
				Thread.currentThread();
				Thread.sleep(200);
			} catch (InterruptedException e) {
				
				e.printStackTrace();
			}
		}
		
	}
	public void paint(){
		this.flushGraphics();
	}
	public void input(){
		
		int k=this.getKeyStates();
		System.out.println("k="+k);
		if((k&GameCanvas.DOWN_PRESSED)>0){
			int[] FRAME_SEQUENCE_DOWN={0, 1, 2};
			p.setFrameSequence(FRAME_SEQUENCE_DOWN);
			p.nextFrame();
			System.out.println(p.getFrame());
			p.move(0, 4);
		}
		if((k&GameCanvas.UP_PRESSED)>0){
			p.setFrameSequence(FRAME_SEQUENCE_UP);
			p.nextFrame();
			p.move(0, -4);
		}
		if((k&GameCanvas.LEFT_PRESSED)>0){
			p.setFrameSequence(FRAME_SEQUENCE_LEFT);
			p.nextFrame();
			p.move(-4, 0);
		}
		if((k&GameCanvas.RIGHT_PRESSED)>0){
			p.setFrameSequence(FRAME_SEQUENCE_RIGHT);
			p.nextFrame();
			p.move(4,0);
		}
		if((k&GameCanvas.FIRE_PRESSED)>0){
			boolean vis=p.isVisible();
			p.setVisible(!vis);
		}
	}
}

------解决方案--------------------
input 是一直在执行的 但是不会进入到if语句里面  J2ME有这样一个机制问题 就是你一直按键但是键值只是第一次才是你想要的键值  System.out.println(p.getFrame()); 应该只打印了一遍 要想实现效果的话  应该在keyPressed里面去定义k