ScrollPosition.isScrollingNotifier returns false when using scroll-wheel and two-finger gesture in trackpad

I have only tried this on a mac device, as a mac app and a web app. When using the trackpad to scroll a view, the ScrollPosition.isScrollingNotifier
returns false.
If I scroll by clicking and dragging it, the notifier returns true.

At least on macos, the default way of scrolling into views is using the two-finger gesture. If you click and drag inside a native app, this one does not scroll, but a Flutter app does.

Steps to Reproduce

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(home: MyListView()));
}
class MyListView extends StatefulWidget {
  @override
  _MyListViewState createState() => _MyListViewState();
}

class _MyListViewState extends State<MyListView> {
  final ScrollController controller = ScrollController();

  @override
  void initState() {
    controller.addListener(() {
      // always prints "scrolling = true"
      print('scrolling = ${controller.position.isScrollingNotifier.value}');
    });
    super.initState();
  }

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(body: ListView.builder(
      controller: controller,
      itemCount: 20,
      itemBuilder: (BuildContext context, int index) {
        return ListTile( 
          title: Text('$index'),
        );
      },
    ),
    );
  }
}

Flutter (Channel dev, 1.26.0-12.0.pre, on macOS 11.1 20C69 darwin-x64, locale en-ES)

I think it has to do with this

flutter/packages/flutter/lib/src/widgets/scroll_position_with_single_context.dart

Line 213 in 3fd3447

goIdle();

As of right now Flutter scroll wheel events are analyzed as a series of single events.

Verified this on latest beta and master using web.

scrolling = false
scrolling = false
scrolling = false
scrolling = false
scrolling = false
scrolling = true
scrolling = true
scrolling = true
scrolling = true
scrolling = true
scrolling = true

flutter doctor -v

[✓] Flutter (Channel master, 1.26.0-18.0.pre.212, on Mac OS X 10.15.4 19E2269
    darwin-x64, locale en-IN)
    • Flutter version 1.26.0-18.0.pre.212 at
      /Users/dhs/documents/Fluttersdk/flutter
    • Framework revision 02d441ea55 (2 days ago), 2021-02-05 17:17:12 -0800
    • Engine revision b04955656c
    • Dart version 2.13.0 (build 2.13.0-0.0.dev)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
    • Android SDK at /Users/dhs/Library/Android/sdk
    • Platform android-30, build-tools 30.0.0
    • Java binary at: /Applications/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6915495)
    • All Android licenses accepted.

[!] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.3, Build version 12C33
    ! CocoaPods 1.9.3 out of date (1.10.0 is recommended).
        CocoaPods is used to retrieve the iOS and macOS platform side's plugin
        code that responds to your plugin usage on the Dart side.
        Without CocoaPods, plugins will not work on iOS or macOS.
        For more info, see https://flutter.dev/platform-plugins
      To upgrade see
      https://guides.cocoapods.org/using/getting-started.html#installation for
      instructions.

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build
      1.8.0_242-release-1644-b3-6915495)

[✓] VS Code (version 1.52.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.18.1

[✓] Connected device (3 available)
    • iPhone 12 Pro Max (mobile) • A5473606-0213-4FD8-BA16-553433949729 • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-14-3 (simulator)
    • macOS (desktop)            • macos                                •
      darwin-x64     • Mac OS X 10.15.4 19E2269 darwin-x64
    • Chrome (web)               • chrome                               •
      web-javascript • Google Chrome 88.0.4324.150

! Doctor found issues in 1 category.

This issue is also seriously affecting scrolling experience for iPad users (#97084). Any updates on this?

@Piinks

hello @Piinks ,any update? our team is struggle in this issue for a long time

Any updates on this? iPadOS.

This is fixed for trackpad, but not for scroll wheel on mouse. I'll have a PR up for it shortly.

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

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ScrollPosition.isScrollingNotifier returns false when using scroll-wheel and two-finger gesture in trackpad #75591

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ScrollPosition.isScrollingNotifier returns false when using scroll-wheel and two-finger gesture in trackpad #75591

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jamesblasco commented on Feb 7, 2021

darshankawar commented on Feb 8, 2021

singularity-s0 commented on Feb 8, 2022

gdutkyle commented on Jun 22, 2022

WithToken commented on Oct 20, 2022

Piinks commented on Oct 24, 2022

github-actions commented on Nov 14, 2022

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