方式1：Timer
在项目中测试，效果不佳；
方式2: Handler
启动任务：
handler.postDelayed(runnable, 3000);
取消任务：
handler.removeCallbacks(runnable);
定义任务：
Runnable runnable = new Runnable(){
@Override
public void run() {
handler.postDelayed(this, 3000);
// TODO Auto-generated method stub
beanList = RemoteService.parseLogisticsBean(param);
if(beanList==null){
beanList = new ArrayList<HashMap<String, String>>();
}else{
adapter.notifyDataSetChanged();
}
}