scrollEvent method

Implementation

scrollEvent() {
  scrollController.addListener(() {
    if (loading || widget.finished) {
      return;
    }
    var position = scrollController.position;
    var pixels = position.pixels;
    var maxScrollExtent = position.maxScrollExtent;
    var isBottom = (pixels + widget.offset) >= maxScrollExtent;
    if (isBottom && widget.load != null) {
      loading = true;
      widget.load!();
    }
  });
}