A Flutter scroll detector example.

scroll_detector_example.dart

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Scroll detector',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        body: ScrollDetector(
          onPointerScroll: print,
          child: Container(
            color: Colors.green,
          ),
        ),
      ),
    );
  }
}

class ScrollDetector extends StatelessWidget {
  final void Function(PointerScrollEvent event) onPointerScroll;
  final Widget child;

  const ScrollDetector({
    Key? key,
    required this.onPointerScroll,
    required this.child,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Listener(
      onPointerSignal: (pointerSignal) {
        if (pointerSignal is PointerScrollEvent) onPointerScroll(pointerSignal);
      },
      child: child,
    );
  }
}