scrollListener method

dynamic scrollListener()

Implementation

scrollListener() {
  if (scrollController.offset >= scrollController.position.maxScrollExtent &&
      !scrollController.position.outOfRange) {
    //get to the bottom
    hideShowLogo(true);
    update();
  }
  if (scrollController.offset <= scrollController.position.minScrollExtent &&
      !scrollController.position.outOfRange) {
    //get to the top
    hideShowLogo(false);
    update();
  }
}