在视图创建的时候，先判断handler是否为空，为空就新建，在视图回收的时候，要移除所有的回调，并置空handler

@Override    public View onCreateView(LayoutInflater inflater, ViewGroup container,                             Bundle savedInstanceState) {               if (mHandler == null) {            mHandler = new Handler() {                @Override                public void handleMessage(Message msg) {                    super.handleMessage(msg);                                 }            };        }        return view;    }   @Override    public void onDestroyView() {        super.onDestroyView();        mHandler.removeCallbacksAndMessages(null);        mHandler = null;    }