infinite_scroll.dart

int _page = 1;
int _limit = 10;

ScrollController _scrollController;

@override
void initState() {
  _setupScrollController();

  _fetch();

  super.initState();
}

void _setupScrollController() {
  _scrollController = ScrollController();

  _scrollController.addListener(_scrollListener);
}

void _scrollListener() {
  if (_scrollController.offset >=
      _scrollController.position.maxScrollExtent) {
    _page++;

    _fetch();
  }
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(
      title: Text('Posts: ${_posts.length}'),
    ),
    body: Builder(
      builder: (context) {
        if (_posts.isEmpty) {
          return Center(
            child: CircularProgressIndicator(),
          );
        }

        return ListView.builder(
          controller: _scrollController,
          itemBuilder: (BuildContext context, int index) {
            if (index == _posts.length) {
              return ListTile(
                title: Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: <Widget>[
                    CircularProgressIndicator(),
                  ],
                ),
              );
            } else {
              final _post = _posts[index];

              return ListTile(
                title: Text(
                  _post['title'],
                ),
                subtitle: Text(
                  _post['body'],
                ),
              );
            }
          },
          itemCount: _posts.length + 1,
        );
      },
    ),
  );
}