Teso_Mobile/lib/Pages/Sub_Pages/Explore/ExploreBusiness.dart

import 'package:flutter/material.dart';
import 'package:teso/Classes/TesoShop.dart';

import 'package:flutter_staggered_grid_view/flutter_staggered_grid_view.dart';
import 'package:teso/Pages/PageWidgets/Explore/business.dart';

class ExploreBusiness extends StatefulWidget {
  final List<TesoShop> businesses;

  const ExploreBusiness({Key key, this.businesses}) : super(key: key);
  @override
  _ExploreBusinessState createState() => _ExploreBusinessState();
}

class _ExploreBusinessState extends State<ExploreBusiness> {
  ScrollController _controller;
  List<TesoShop> show = [];
  int count = 0;

  Future<void> fetchImages() async {
    try {
      count = show.length;
      for (int i = 0; i <= 9; i++) {
        if (widget.businesses.length > count)
          setState(() {
            show.add(widget.businesses.elementAt(count));
            count++;
            imageCache.clear();
          });
      }
    } catch (e) {
      print(e);
    }
  }

  @override
  void didUpdateWidget(covariant ExploreBusiness oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.businesses != widget.businesses ||
        widget.businesses.length == 0) {
      show = [];
      fetchImages();
    }
  }

  void _scrollListener() {
    if (_controller.offset >= _controller.position.maxScrollExtent &&
        !_controller.position.outOfRange) {
      fetchImages();
    }
  }

  @override
  void initState() {
    _controller = ScrollController();
    _controller.addListener(_scrollListener);
    count = 0;
    fetchImages();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      child: StaggeredGridView.count(
        controller: _controller,
        crossAxisCount: 2,
        children: List.generate(show.length, (int index) {
          return buildBusiness(context, show.elementAt(index));
        }),
        staggeredTiles: List.generate(
          show.length,
          (int index) {
            return StaggeredTile.fit(1);
          },
        ),
      ),
    );
  }
}