MediaPlayer.getCurrentPosition IllegalStateException错误

除了判断player是否等于null，还要判断isplaying，否者报错
public void run() {
        // TODO Auto-generated method stub
        boolean isTrue=true;
        while(isTrue=true){
            try{
                Thread.sleep(1000);
            }catch(InterruptedException e){
                e.printStackTrace();
            }
            if(player==null){
                isTrue=false;
            }else{
                if(player.isPlaying()){//这是插入的代码
                int position=player.getCurrentPosition();
                Message msg=handler.obtainMessage();
                msg.what=position;
                handler.sendEmptyMessage(position);
                }
            }
                
        }