Unexpected behaviour with ColorScheme.fromSeed and Brightness.dark

Is there an existing issue for this?

I have searched the existing issues
I have read the guide to filing a bug

Steps to reproduce

Create a new Flutter project
Inside the MaterialApp -> ThemeData change the brightness from Brightness.light to Brightness.dark
Launch the app

Expected results

The app launches correctly without issues.

Actual results

The Debug Console shows this error:

════════ Exception caught by widgets library ═══════════════════════════════════
The following assertion was thrown building MyApp(dirty):
'package:flutter/src/material/theme_data.dart': Failed assertion: line 459 pos 12: 'colorScheme?.brightness == null || brightness == null || colorScheme!.brightness == brightness': is not true.
theme_data.dart:459

The relevant error-causing widget was
MyApp
main.dart:4
When the exception was thrown, this was the stack
#2      new ThemeData
theme_data.dart:459
#3      MyApp.build
main.dart:14
#4      StatelessElement.build
framework.dart:5156
#5      ComponentElement.performRebuild
framework.dart:5086
#6      Element.rebuild
framework.dart:4805
#7      BuildOwner.buildScope
framework.dart:2780
#8      WidgetsBinding.drawFrame
binding.dart:903
#9      RendererBinding._handlePersistentFrameCallback
binding.dart:358
#10     SchedulerBinding._invokeFrameCallback
binding.dart:1284
#11     SchedulerBinding.handleDrawFrame
binding.dart:1214
#12     SchedulerBinding.scheduleWarmUpFrame.<anonymous closure>
binding.dart:939
#16     _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:189:12)

Code sample

This code works:

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
        brightness: Brightness.light,
      ),
      home: Container(),
    );
  }
}

This code does NOT work:

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
        brightness: Brightness.dark,
      ),
      home: Container(),
    );
  }
}

This code works:

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorSchemeSeed: Colors.deepPurple,
        useMaterial3: true,
        brightness: Brightness.light,
      ),
      home: Container(),
    );
  }
}

This code works:

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorSchemeSeed: Colors.deepPurple,
        useMaterial3: true,
        brightness: Brightness.dark,
      ),
      home: Container(),
    );
  }
}

Issue

If I use colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple) It works only with brightness: Brightness.light but not with brightness: Brightness.dark
If I use colorSchemeSeed: Colors.deepPurple It works with both brightness: Brightness.light and brightness: Brightness.dark

Flutter Doctor output

[✓] Flutter (Channel stable, 3.10.1, on Fedora Linux 37 (KDE Plasma) 6.2.15-200.fc37.x86_64, locale it_IT.UTF-8)
    • Flutter version 3.10.1 on channel stable at /home/alberto/tools/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision d3d8effc68 (8 giorni fa), 2023-05-16 17:59:05 -0700
    • Engine revision b4fb11214d
    • Dart version 3.0.1
    • DevTools version 2.23.1

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.2)
    • Android SDK at /home/alberto/Android/Sdk
    • Platform android-33-ext4, build-tools 33.0.2
    • Java binary at: /home/alberto/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-0/222.4459.24.2221.9971841/jbr/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b802.4-9586694)
    • All Android licenses accepted.

[✓] Chrome - develop for the web
    • CHROME_EXECUTABLE = /opt/brave.com/brave/brave-browser

[✓] Linux toolchain - develop for Linux desktop
    • clang version 15.0.7 (Fedora 15.0.7-2.fc37)
    • cmake version 3.26.4
    • ninja version 1.10.2
    • pkg-config version 1.8.0

[✓] Android Studio (version 2022.2)
    • Android Studio at /home/alberto/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-0/222.4459.24.2221.9971841
    • 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 17.0.6+0-17.0.6b802.4-9586694)

[✓] IntelliJ IDEA Community Edition (version 2023.1)
    • IntelliJ at /home/alberto/.local/share/JetBrains/Toolbox/apps/IDEA-C/ch-0/231.8770.65
    • 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

[✓] VS Code (version 1.78.2)
    • VS Code at /usr/share/code
    • Flutter extension version 3.64.0

[✓] Connected device (2 available)
    • Linux (desktop) • linux  • linux-x64      • Fedora Linux 37 (KDE Plasma) 6.2.15-200.fc37.x86_64
    • Chrome (web)    • chrome • web-javascript • Brave Browser 113.1.51.118

[✓] Network resources
    • All expected network resources are available.

• No issues found!

Thanks for your report. This issue is reproducible on the latest stable and master channels.

For more information about the last condition from the failed assertion (colorScheme!.brightness == brightness):

flutter/packages/flutter/lib/src/material/color_scheme.dart

Line 160 in 54d001d

Brightness brightness = Brightness.light,

It is in conflict with brightness: Brightness.dark from ThemeData.

flutter doctor -v (stable and master)

[✓] Flutter (Channel stable, 3.10.2, on macOS 13.0.1 22A400 darwin-x64, locale en-VN)
    • Flutter version 3.10.2 on channel stable at /Users/huynq/Documents/GitHub/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 9cd3d0d9ff (22 hours ago), 2023-05-23 20:57:28 -0700
    • Engine revision 90fa3ae28f
    • Dart version 3.0.2
    • DevTools version 2.23.1

[✓] Android toolchain - develop for Android devices (Android SDK version 32.0.0)
    • Android SDK at /Users/huynq/Library/Android/sdk
    • Platform android-33, build-tools 32.0.0
    • ANDROID_HOME = /Users/huynq/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b802.4-9586694)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 14.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 14E222b
    • CocoaPods version 1.11.3

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

[✓] Android Studio (version 2022.2)
    • 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 17.0.6+0-17.0.6b802.4-9586694)

[✓] VS Code (version 1.78.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.64.0

[✓] Connected device (3 available)
    • RMX2001 (mobile) • EUYTFEUSQSRGDA6D • android-arm64  • Android 11 (API 30)
    • macOS (desktop)  • macos            • darwin-x64     • macOS 13.0.1 22A400 darwin-x64
    • Chrome (web)     • chrome           • web-javascript • Google Chrome 113.0.5672.126

[✓] Network resources
    • All expected network resources are available.

• No issues found!

[!] Flutter (Channel master, 3.11.0-13.0.pre.20, on macOS 13.0.1 22A400 darwin-x64, locale en-VN)
    • Flutter version 3.11.0-13.0.pre.20 on channel master at /Users/huynq/Documents/GitHub/flutter_master
    ! Warning: `flutter` on your path resolves to /Users/huynq/Documents/GitHub/flutter/bin/flutter, which is not inside your current Flutter SDK checkout at /Users/huynq/Documents/GitHub/flutter_master. Consider adding /Users/huynq/Documents/GitHub/flutter_master/bin to the front of your path.
    ! Warning: `dart` on your path resolves to /Users/huynq/Documents/GitHub/flutter/bin/dart, which is not inside your current Flutter SDK checkout at /Users/huynq/Documents/GitHub/flutter_master. Consider adding /Users/huynq/Documents/GitHub/flutter_master/bin to the front of your path.
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 5eacfe62bd (22 minutes ago), 2023-05-24 21:47:08 -0400
    • Engine revision 1bed04a437
    • Dart version 3.1.0 (build 3.1.0-142.0.dev)
    • DevTools version 2.23.1
    • If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and upgrades.

[✓] Android toolchain - develop for Android devices (Android SDK version 32.0.0)
    • Android SDK at /Users/huynq/Library/Android/sdk
    • Platform android-33, build-tools 32.0.0
    • ANDROID_HOME = /Users/huynq/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b802.4-9586694)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 14.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 14E222b
    • CocoaPods version 1.11.3

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

[✓] Android Studio (version 2022.2)
    • 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 17.0.6+0-17.0.6b802.4-9586694)

[✓] VS Code (version 1.78.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.64.0

[✓] Connected device (3 available)
    • RMX2001 (mobile) • EUYTFEUSQSRGDA6D • android-arm64  • Android 11 (API 30)
    • macOS (desktop)  • macos            • darwin-x64     • macOS 13.0.1 22A400 darwin-x64
    • Chrome (web)     • chrome           • web-javascript • Google Chrome 113.0.5672.126

[✓] Network resources
    • All expected network resources are available.

! Doctor found issues in 1 category.

@huycozy

@huycozy is correct. To correct a dark color scheme (dark theme) you need to override the color scheme's brightness parameter:

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: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple, brightness: Brightness.dark),
        useMaterial3: true,
      ),
      home: Container(),
    );
  }
}

@HansMuller

This issue is assigned to @HansMuller but has had no recent status updates. Please consider unassigning this issue if it is not going to be addressed in the near future. This allows people to have a clearer picture of what work is actually planned. Thanks!

Provide a helpful error message when `ColorScheme.brightness` doesn't…

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.

Navigation Menu

Repository navigation

Unexpected behaviour with ColorScheme.fromSeed and Brightness.dark #127523

Is there an existing issue for this?

Steps to reproduce

Expected results

Actual results

Code sample

Issue

Flutter Doctor output

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Unexpected behaviour with ColorScheme.fromSeed and Brightness.dark #127523

Description

Is there an existing issue for this?

Steps to reproduce

Expected results

Actual results

Code sample

Issue

Flutter Doctor output

Activity

huycozy commented on May 25, 2023

HansMuller commented on May 31, 2023

flutter-triage-bot commented on Oct 18, 2023

github-actions commented on Nov 20, 2023

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions