GestureDetector and IgnorePointer cause slow onTap callback

[hgraceb]

I need to display the mask and ignore the events of other widgets when the mask is displayed. When I remove onDoubleTap or IgnorePointer, the onTap method calls back in a very quick instant. But if I use onDoubleTap and IgnorePointer at the same time, the onTap callback of the mask has a visible delay. What am I doing wrong and how can I fix it?

Sample

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

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Tests',
      home: const MyHomePage(),
      debugShowCheckedModeBanner: false,
      scrollBehavior: const MaterialScrollBehavior().copyWith(
        dragDevices: PointerDeviceKind.values.toSet(),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  bool _visible = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Home')),
      body: Stack(children: [
        GestureDetector(
          onDoubleTap: () {},
          child: ListView(
            children: List.generate(100, (i) {
              return ListTile(title: Text('Item $i'));
            }),
          ),
        ),
        AnimatedOpacity(
          opacity: _visible ? 1.0 : 0.0,
          duration: const Duration(milliseconds: 300),
          child: IgnorePointer(
            ignoring: !_visible,
            child: Container(color: Colors.blue.withOpacity(0.8)),
          ),
        ),
        GestureDetector(onTap: () => setState(() => _visible = !_visible)),
      ]),
    );
  }
}

Logs

Logs

Analyzing fluttest...
No issues found! (ran in 1.2s)

[!] Flutter (Channel unknown, 3.3.3, on Microsoft Windows [版本 10.0.19044.2604], locale zh-CN)
    ! Flutter version 3.3.3 on channel unknown at D:\***\flutter
    ! Upstream repository unknown
    • Framework revision 18a827f393 (5 months ago), 2022-09-28 10:03:14 -0700
    • Engine revision 5c984c26eb
    • Dart version 2.18.2
    • DevTools version 2.15.0

[√] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
    • Android SDK at C:\Users\***\AppData\Local\Android\sdk
    • Platform android-33, build-tools 33.0.0
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)
    • All Android licenses accepted.

[√] Chrome - develop for the web
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.11.18)
    • Visual Studio at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community
    • Visual Studio Community 2019 version 16.11.32802.440
    • Windows 10 SDK version 10.0.19041.0

[√] Android Studio (version 2021.3)
    • Android Studio at C:\Program Files\Android\Android Studio
    • 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 11.0.13+0-b1751.21-8125866)

[√] VS Code, 64-bit edition (version 1.69.1)
    • VS Code at C:\Program Files\Microsoft VS Code
    • Flutter extension can be installed from:
       https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[√] Connected device (3 available)
    • Windows (desktop) • windows • windows-x64    • Microsoft Windows [版本 10.0.19044.2604]
    • Chrome (web)      • chrome  • web-javascript • Google Chrome 110.0.5481.178
    • Edge (web)        • edge    • web-javascript • Microsoft Edge 108.0.1462.54

[√] HTTP Host Availability
    • All required HTTP hosts are available

! Doctor found issues in 1 category.

[clragon]

When GestureDetector has a onDoubleTap, it will add a short delay to wait for the potential second tap before deciding what to do. This is because tapping and double tapping are treated as exclusive actions. Unfortunatey, GestureDetector does not have a parameter to change this behaviour.

There are some other issues where this problem is also discussed, though I can't find them right now.

[hgraceb]

When GestureDetector has a onDoubleTap, it will add a short delay to wait for the potential second tap before deciding what to do. This is because tapping and double tapping are treated as exclusive actions. Unfortunatey, GestureDetector does not have a parameter to change this behaviour.

There are some other issues where this problem is also discussed, though I can't find them right now.

Thank you very much. I have changed the keywords to onTap and onDoubleTap and have indeed found some previous issues. However, it is frustrating that there is still no very good solution at present. At least in the scenario of my example, adjusting the kDoubleTapTimeout or using SerialTapGestureRecognizer are not particularly satisfactory.

Nevertheless, thank you for your reply. I think I should find another way to reduce the perceived delay for the user.

[darshankawar]

@hgraceb
It doesn't seem to be a bug but intended functionality. The double tap can happen up to 300ms after the first tap up. You may want to check kDoubleTapTimeout here: https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/gestures/constants.dart#L31

There's also an open proposal that looks closely related to your case / query: #106170 and #113906 in which you can follow-up for further updates. I'll close this in favor of these linked issues.

Please do leave a thumbs up on the original author's post so we can track and prioritize the issue base on severity and demand. Thanks!

[github-actions]

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.