颤动网页：无法在鼠标按下时滚动(拖动)(颤动2.5+) [英] Flutter Web: Cannot scroll with mouse down (drag) (Flutter 2.5+)

问题描述

[更新]

我可以确认这个问题发生在2.5以上的颤动中。使用2.2.3就可以了。问题变成了为什么在2.5版中删除了这一功能？以及如何在Ffltter 2.5中启用它？

[来源问题]

我正在通过桌面浏览器在Ffltter Web上使用SingleChildScrollView。滚动仅适用于鼠标滚轮，但不适用于鼠标单击(拖动)。我如何像移动设备一样将鼠标点击映射到触摸和滚动？

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: SingleChildScrollView(
        child: Column(
          children: List<Widget>.generate(50, (i) => Text(i.toString())).toList(),
        ),
      ),
    );
  }
}

flutter doctor -v
[✓] Flutter (Channel master, 2.6.0-6.0.pre.6, on Ubuntu 20.04.3 LTS 5.11.0-34-generic, locale en_US.UTF-8)
    • Flutter version 2.6.0-6.0.pre.6 at /home/XXX
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 0c5431d99c (12 days ago), 2021-09-05 22:31:02 -0400
    • Engine revision b9c633900e
    • Dart version 2.15.0 (build 2.15.0-82.0.dev)

[✓] Chrome - develop for the web
    • Chrome at google-chrome

[✓] Connected device (2 available)
    • Linux (desktop) • linux  • linux-x64      • Ubuntu 20.04.3 LTS 5.11.0-34-generic
    • Chrome (web)    • chrome • web-javascript • Google Chrome 93.0.4577.82

推荐答案

颤动更改2.5后的鼠标滚动行为。有关详细信息，请参阅this。

class MyCustomScrollBehavior extends MaterialScrollBehavior {
  // Override behavior methods and getters like dragDevices
  @override
  Set<PointerDeviceKind> get dragDevices => { 
    PointerDeviceKind.touch,
    PointerDeviceKind.mouse,
    // etc.
  };
}

// ScrollBehavior can be set for a specific widget.
final ScrollController controller = ScrollController();
ScrollConfiguration(
  behavior: MyCustomScrollBehavior(),
  child: ListView.builder(
    controller: controller,
    itemBuilder: (BuildContext context, int index) {
     return Text('Item $index');
    }
  ),
);

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