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Discrete Slider/RangeSlider has interpolation (?) errors #39510

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flutter/packages
#13022
Closed
Discrete Slider/RangeSlider has interpolation (?) errors#39510
flutter/packages
#13022
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hannah-hyj
Labels
P2Important issues not at the top of the work listfound in release: 3.3Found to occur in 3.3found in release: 3.7Found to occur in 3.7has reproducible stepsThe issue has been confirmed reproducible and is ready to work onp: material_uimaterial_ui package in flutter/packagespackageflutter/packages repository. See also p: labels.team-designOwned by Design Languages teamtriaged-designTriaged by Design Languages team

Description

@repentsinner
repentsinner
opened on Aug 29, 2019

Steps to Reproduce

  1. Create a discrete Slider/RangeSlider with min:0.0, max:35.0, divisions: 35 (or see main.dart)
  2. Build on Windows & run on a Pixel 2 or build on MacOS and run on an iPhone 7.
  3. Slide any of the thumbs to the 29th position.
  4. Expect the value to be 29.0, but instead receive 29.000000000000004

This also happens with:

max/divisions value
22 14.999999999999998
23 12.999999999999998
25 7.000000000000001, 14.000000000000002
...
35 29.000000000000004
38 21.000000000000004
39 25.000000000000004, 30.999999999999996
...

Current workaround is to insert .roundToDouble() methods in all of the onChange* callbacks to clean up the values before passing them out to the consumer.

Thanks for considering!

Logs

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

[√] Flutter (Channel stable, v1.7.8+hotfix.4, on Microsoft Windows [Version 10.0.18362.327], locale en-US)
    • Flutter version 1.7.8+hotfix.4 at C:\Users\deg\Development\flutter
    • Framework revision 20e59316b8 (6 weeks ago), 2019-07-18 20:04:33 -0700
    • Engine revision fee001c93f
    • Dart version 2.4.0

 
[√] Android toolchain - develop for Android devices (Android SDK version 29.0.1)
    • Android SDK at C:\Users\deg\AppData\Local\Android\sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-29, build-tools 29.0.1
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
    • All Android licenses accepted.

[√] Android Studio (version 3.4)
    • Android Studio at C:\Program Files\Android\Android Studio
    • Flutter plugin version 37.1.1
    • Dart plugin version 183.6270
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)

[√] VS Code (version 1.37.1)
    • VS Code at C:\Users\deg\AppData\Local\Programs\Microsoft VS Code
    • Flutter extension version 3.3.0

[√] Connected device (1 available)
    • Pixel 2 • FA79E1A01225 • android-arm64 • Android 9 (API 28)

• No issues found!

Activity

  1. BondarenkoStas
    added
    a: text inputEntering text in a text field or keyboard related problems
    frameworkflutter/packages/flutter repository. See also f: labels.
    on Aug 30, 2019
  2. HansMuller
    added
    p: material_uimaterial_ui package in flutter/packages
    on Aug 30, 2019

  3. HansMuller commented on Aug 30, 2019

    @HansMuller
    HansMuller
    on Aug 30, 2019
    Contributor

    CC @clocksmith - maybe we're missing a clamp?

  4. jonans commented on Apr 23, 2020

    @jonans
    jonans
    on Apr 23, 2020

    Seeing the same problem probably due to floating point error. Any plans on a fix ?

                    Slider.adaptive(value: widget._val,
                          label: widget._val.toString(),
                          onChanged: (x){
                              widget._val= x; 
                              setState((){});
                          },
                          min: 0,
                          max: 5,
                          divisions: 5 ~/ 0.2 ,
                 )

    slider-rounding-error

  5. clocksmith
    self-assigned this
    on Apr 23, 2020
  6. clocksmith
    removed their assignment
    on Jun 18, 2020

  7. markusaksli-nc commented on Jul 20, 2020

    @markusaksli-nc
    markusaksli-nc
    on Jul 20, 2020
    Contributor

    Reproducible on the latest master 1.21.0-2.0.pre.66.

    flutter doctor -v 
    [√] Flutter (Channel master, 1.21.0-2.0.pre.66, on Microsoft Windows [Version 10.0.18362.900], locale et-EE)
   • Flutter version 1.21.0-2.0.pre.66 at C:\Development\flutter_master
   • Framework revision 54c9441723 (2 days ago), 2020-07-17 18:56:12 -0400
   • Engine revision d327828632
   • Dart version 2.9.0 (build 2.9.0-21.0.dev 9dca49e71e)


[√] Android toolchain - develop for Android devices (Android SDK version 30.0.0)
   • Android SDK at C:\Users\Isa\AppData\Local\Android\sdk
   • Platform android-30, build-tools 30.0.0
   • Java binary at: C:\Users\Isa\AppData\Local\JetBrains\Toolbox\apps\AndroidStudio\ch-0\193.6626763\jre\bin\java
   • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
   • All Android licenses accepted.

[√] Chrome - develop for the web
   • Chrome at C:\Program Files (x86)\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.6.4)
   • Visual Studio at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community
   • Visual Studio Community 2019 version 16.6.30309.148
   • Windows 10 SDK version 10.0.18362.0

[√] Android Studio (version 4.0)
   • Android Studio at C:\Users\Isa\AppData\Local\JetBrains\Toolbox\apps\AndroidStudio\ch-0\193.6626763
   • Flutter plugin version 47.1.2
   • Dart plugin version 193.7361
   • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)

[√] VS Code (version 1.47.2)
   • VS Code at C:\Users\Isa\AppData\Local\Programs\Microsoft VS Code
   • Flutter extension version 3.12.2

[√] Connected device (5 available)
   • SM G950F (mobile)       • ce12171c51cc001c03 • android-arm64  • Android 9 (API 28)
   • sdk gphone x86 (mobile) • emulator-5554      • android-x86    • Android 11 (API 30) (emulator)
   • Windows (desktop)       • windows            • windows-x64    • Microsoft Windows [Version 10.0.18362.900]
   • Web Server (web)        • web-server         • web-javascript • Flutter Tools
   • Chrome (web)            • chrome             • web-javascript • Google Chrome 84.0.4147.89

• No issues found!
  8. markusaksli-nc
    added
    found in release: 1.21Found to occur in 1.21
    has reproducible stepsThe issue has been confirmed reproducible and is ready to work on
    on Jul 20, 2020

  9. thecalamiity commented on Aug 24, 2020

    @thecalamiity
    thecalamiity
    on Aug 24, 2020
    Contributor

    You mentioned this issue in your merged PR @guidezpl . Should this be closed?

  10. markusaksli-nc commented on Aug 24, 2020

    @markusaksli-nc
    markusaksli-nc
    on Aug 24, 2020
    Contributor

    That PR was just a fix for #60715. This is still reproducible on 1.22.0-2.0.pre.36.

    flutter doctor -v 
    [√] Flutter (Channel master, 1.22.0-2.0.pre.36, on Microsoft Windows [Version 10.0.19041.450], locale en-US)
    • Flutter version 1.22.0-2.0.pre.36 at C:\Development\flutter_master
    • Framework revision d30e36ba8c (2 days ago), 2020-08-21 22:36:03 -0400
    • Engine revision d495da20d0
    • Dart version 2.10.0 (build 2.10.0-49.0.dev)

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.1)
    • Android SDK at C:\Users\marku\AppData\Local\Android\sdk
    • Platform android-30, build-tools 30.0.1
    • Java binary at: C:\Users\marku\AppData\Local\JetBrains\Toolbox\apps\AndroidStudio\ch-0\193.6626763\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
    • All Android licenses accepted.

[√] Chrome - develop for the web
    • Chrome at C:\Program Files (x86)\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.6.5)
    • Visual Studio at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community
    • Visual Studio Community 2019 version 16.6.30320.27
    • Windows 10 SDK version 10.0.18362.0

[√] Android Studio (version 4.0)
    • Android Studio at C:\Users\marku\AppData\Local\JetBrains\Toolbox\apps\AndroidStudio\ch-0\193.6626763
    • Flutter plugin version 47.1.2
    • Dart plugin version 193.7361
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)

[√] Connected device (4 available)
    • sdk gphone x86 arm (mobile) • emulator-5554 • android-x86    • Android 11 (API 30) (emulator)
    • Windows (desktop)           • windows       • windows-x64    • Microsoft Windows [Version 10.0.19041.450]
    • Web Server (web)            • web-server    • web-javascript • Flutter Tools
    • Chrome (web)                • chrome        • web-javascript • Google Chrome 84.0.4147.125

• No issues found!
  11. markusaksli-nc
    added
    found in release: 1.22Found to occur in 1.22
    on Aug 24, 2020

  12. danielgomezrico commented on Jul 31, 2021

    @danielgomezrico
    danielgomezrico
    on Jul 31, 2021
    Contributor

    This is still happening on flutter 2.2.0

  13. apoleo88 commented on Nov 18, 2021

    @apoleo88
    apoleo88
    on Nov 18, 2021

    It is, also if you use

    min: 40,
max: 42,
division: 10,

    and you slide to the last value you will get as value 42.00000000000001 that is greater than max and get a bigger Exception:

    'package:flutter/src/material/slider.dart': Failed assertion: line 166 pos 15: 'value >= min && value <= max': is not true.

    And it won't render!

  14. 21 remaining items

  15. flutter-triage-bot
    added
    team-designOwned by Design Languages team
    triaged-designTriaged by Design Languages team
    on Jul 8, 2023
  16. gnprice
    removed
    a: text inputEntering text in a text field or keyboard related problems
    on Jul 18, 2023
  17. Hixie
    removed
    multiteam-retriage-candidate
    on Mar 6, 2024

  18. J3Unknown commented on Nov 1, 2025

    @J3Unknown
    J3Unknown
    on Nov 1, 2025

    is this issue still exist or has been solved?

  19. hannah-hyj
    self-assigned this
    on Jun 8, 2026
  20. Piinks
    added
    packageflutter/packages repository. See also p: labels.
    and removed
    frameworkflutter/packages/flutter repository. See also f: labels.
    on Aug 17, 2026
  21. hannah-hyj
    added 2 commits that reference this issue on Sep 25, 2026

    [material_ui] Fix floating-point rounding errors for discrete Slider …

    7f2957f

    [material_ui] Fix floating-point rounding errors for discrete Slider …

    919cd62
  22. auto-submit
    closed this as completedin packages#13022on Sep 28, 2026
  23. github-project-automation
    moved this from Todo to Done in Slider Updateson Sep 28, 2026
  24. burakJs
    added a commit that references this issue on Sep 28, 2026

    [material_ui] Fix floating-point rounding errors for discrete Slider …

    bcc6dcf

  25. github-actions commented on Oct 12, 2026

    @github-actions
    github-actionsBot
    on Oct 12, 2026 – with 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.

  26. github-actions
    locked as resolved and limited conversation to collaborators on Oct 12, 2026
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P2Important issues not at the top of the work listfound in release: 3.3Found to occur in 3.3found in release: 3.7Found to occur in 3.7has reproducible stepsThe issue has been confirmed reproducible and is ready to work onp: material_uimaterial_ui package in flutter/packagespackageflutter/packages repository. See also p: labels.team-designOwned by Design Languages teamtriaged-designTriaged by Design Languages team

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