PullToRefreshWidget(
    isRefreshEnable: true,
    headerBuilder: _buildHeaderWidget,
    onRefresh: _handleRefresh,
    isLoadMoreEnable: hasMore,
    onLoadMore: _onLoadMore,
    footerBuilder: _buildFootWidget,
    child: ListView.builder(
        itemCount: items.length,
        itemBuilder: (context, index) {
        return new ListTile(
            title: Text("Index$index"),
        );
    }));

DefaultRefreshHeaderWidget _buildHeaderWidget(BuildContext context) {
    return DefaultRefreshHeaderWidget();
  }

Widget _buildFootWidget(BuildContext context) {
    return new Container(
      alignment: Alignment.center,
      height: 60.0,
      child: new Center(
        child: new Row(
            textDirection: TextDirection.ltr,
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              new Text("正在加载中。。。"),
              new CircularProgressIndicator(strokeWidth: 2.0)
            ]),
      ),
    );
  }

  Future<Null> _handleRefresh() async {
    await Future.delayed(Duration(seconds: 50), () {
      setState(() {
        items.clear();
        items = List.generate(40, (i) => i);
      });
    });
  }

  Future<Null> _onLoadMore() async {
    await Future.delayed(Duration(seconds: 50), () {
      setState(() {
        if (index == 2) {
          hasMore = false;
        }
        int length = items.length;
        index++;
        items.addAll(List.generate(16, (i) => i + length));
      });
    });
  }