flutter_infinite_scroll_main_3.dart

Widget getBody() {
    if (_photos.isEmpty) {
      if (_loading) {
        return Center(
            child: Padding(
          padding: const EdgeInsets.all(8),
          child: CircularProgressIndicator(),
        ));
      } else if (_error) {
        return Center(
            child: InkWell(
          onTap: () {
            setState(() {
              _loading = true;
              _error = false;
              fetchPhotos();
            });
          },
          child: Padding(
            padding: const EdgeInsets.all(16),
            child: Text("Error while loading photos, tap to try agin"),
          ),
        ));
      }
    } else {
      return ListView.builder(
          itemCount: _photos.length + (_hasMore ? 1 : 0),
          itemBuilder: (context, index) {
            if (index == _photos.length - _nextPageThreshold) {
              fetchPhotos();
            }
            if (index == _photos.length) {
              if (_error) {
                return Center(
                    child: InkWell(
                  onTap: () {
                    setState(() {
                      _loading = true;
                      _error = false;
                      fetchPhotos();
                    });
                  },
                  child: Padding(
                    padding: const EdgeInsets.all(16),
                    child: Text("Error while loading photos, tap to try agin"),
                  ),
                ));
              } else {
                return Center(
                    child: Padding(
                  padding: const EdgeInsets.all(8),
                  child: CircularProgressIndicator(),
                ));
              }
            }
            final Photo photo = _photos[index];
            return Card(
              child: Column(
                children: <Widget>[
                  Image.network(
                    photo.thumbnailUrl,
                    fit: BoxFit.fitWidth,
                    width: double.infinity,
                    height: 160,
                  ),
                  Padding(
                    padding: const EdgeInsets.all(16),
                    child: Text(photo.title,
                        style: TextStyle(
                            fontWeight: FontWeight.bold, fontSize: 16)),
                  ),
                ],
              ),
            );
          });
    }
    return Container();
  }