import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';

class MyMobileBody extends StatefulWidget {
  const MyMobileBody({Key? key}) : super(key: key);

  @override
  State<MyMobileBody> createState() => _MyMobileBodyState();
}

class _MyMobileBodyState extends State<MyMobileBody> {
  ScrollController controller = ScrollController();
  bool _isScrollingDown = false;
  List<int> text = [
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    8,
    9,
    10,
    11,
    12,
    13,
    14,
    15,
    16,
    17,
    18,
    19,
    20
  ];

  @override
  void initState() {
    WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
      controller.position.isScrollingNotifier.addListener(() {
        if (controller.position.maxScrollExtent == controller.offset) {
          print('end');
        }

        if (controller.position.minScrollExtent == controller.offset) {
          print('start');
        }

        if (!controller.position.isScrollingNotifier.value) {
          print('scroll is stopped');
        } else {
          print('scroll is started');
        }
      });
    });

    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        children: [
          NotificationListener<UserScrollNotification>(
            onNotification: (notification) {
              final ScrollDirection direction = notification.direction;
              setState(() {
                if (direction == ScrollDirection.reverse) {
                _isScrollingDown = false;
                } else if (direction == ScrollDirection.forward) {
                  _isScrollingDown = true;
                }
              });
              return true;
            },
            child: Expanded(
              child: ListView.separated(
                separatorBuilder: (context, index) => SizedBox(height: 10,),
                controller: controller,
                itemCount: text.length,
                itemBuilder: (context, index) {
                  return Container(
                    height: 100,
                    color: Colors.red,
                    child: Center(
                      child: Text(index.toString()),
                    ),
                  );
                },
              ),
            ),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          if (_isScrollingDown) {

            controller.animateTo(
              controller.position.minScrollExtent,
              duration: Duration(seconds: 2),
              curve: Curves.easeIn,
            );

          } else {
            controller.animateTo(
              controller.position.maxScrollExtent,
              duration: Duration(seconds: 2),
              curve: Curves.easeIn,
            );
          }
        },
        child: Icon(_isScrollingDown ? Icons.arrow_upward : Icons.arrow_downward),
      ),
    );
  }
}