WidgetsApp: Changing supportedLocales fails to update the locale #117210
Description
When providing supportedLocales to a WidgetsApp (in this case, a MaterialApp), it doesn't update the internal _locale field in didUpdateWidget.
The workaround is to provide a specific locale via the locale field. (as to be seen on line 23)
Steps to Reproduce
- Execute
flutter runon the code sample - Press button on page
- Observe that the text above the button doesn't change.
- Uncomment workaround in line 23 and try again.
Expected results: Text respectively the Locale (_locale in WidgetsApp) changes.
Actual results: _locale in WidgetsApp is still the same, nothing changes.
Code sample
import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({super.key});
@override
State<MyApp> createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
List<Locale> supportedLocales = [const Locale("de")];
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
// Workaround: Overrides the _locale from WidgetsApp
// locale: supportedLocales[0],
supportedLocales: supportedLocales,
localizationsDelegates: GlobalMaterialLocalizations.delegates,
routes: {
'/': (context) => MyHomePage(onPress: () {
setState(() {
supportedLocales = [const Locale("en")];
});
}),
},
initialRoute: "/",
);
}
}
class MyHomePage extends StatelessWidget {
final VoidCallback onPress;
const MyHomePage({super.key, required this.onPress});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text("Flutter Demo Home Page")),
body: Center(
child: Column(
children: [
Text("Current locale: ${Localizations.localeOf(context)}"),
ElevatedButton(
onPressed: () => onPress.call(),
child: const Text("Press me to change locale"),
),
],
),
),
);
}
}
flutter doctor -v
[✓] Flutter (Channel stable, 3.3.9, on Manjaro Linux 6.0.11-1-MANJARO, locale de_AT.UTF-8)
• Flutter version 3.3.9 on channel stable at /home/shamader/tools/flutter/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision b8f7f1f986 (vor 3 Wochen), 2022-11-23 06:43:51 +0900
• Engine revision 8f2221fbef
• Dart version 2.18.5
• DevTools version 2.15.0
[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
• Android SDK at /mnt/Daten/tools/Android/Sdk
• Platform android-33, build-tools 33.0.0
• Java binary at: /home/shamader/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-0/213.7172.25.2113.9123335/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_EXECUTABLE = /usr/bin/chromium
[✗] Linux toolchain - develop for Linux desktop
• clang version 14.0.6
✗ CMake is required for Linux development.
It is likely available from your distribution (e.g.: apt install cmake), or can be downloaded from https://cmake.org/download/
✗ ninja is required for Linux development.
It is likely available from your distribution (e.g.: apt install ninja-build), or can be downloaded from https://github.com/ninja-build/ninja/releases
• pkg-config version 1.8.0
[✓] Android Studio (version 2021.3)
• Android Studio at /home/shamader/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-0/213.7172.25.2113.9123335
• Flutter plugin version 71.1.3
• Dart plugin version 213.7433
• Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)
[!] Android Studio (version 2022.1)
• Android Studio at /home/shamader/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-1/221.6008.13.2211.9301383
• 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
✗ Unable to find bundled Java version.
• Try updating or re-installing Android Studio.
[!] Android Studio (version 2022.2)
• Android Studio at /home/shamader/.local/share/JetBrains/Toolbox/apps/AndroidStudio/ch-2/222.4345.14.2221.9321504
• 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
✗ Unable to find bundled Java version.
• Try updating or re-installing Android Studio.
[✓] Connected device (4 available)
• SM T500 (mobile) • R9AR800H8RK • android-arm64 • Android 12 (API 31)
• M2103K19PG (mobile) • xwcm955djrrslnpj • android-arm64 • Android 12 (API 31)
• Linux (desktop) • linux • linux-x64 • Manjaro Linux 6.0.11-1-MANJARO
• Chrome (web) • chrome • web-javascript • Chromium 108.0.5359.94 Arch Linux
[✓] HTTP Host Availability
• All required HTTP hosts are available
! Doctor found issues in 3 categories.
Missing statement location
WidgetsApp Code which is missing an update statement taking supportedLocales into account.
flutter/packages/flutter/lib/src/widgets/app.dart
Lines 1335 to 1347 in da7b832
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Important issues not at the top of the work listSupporting other languages or locales. (aka i18n)flutter/packages/flutter/material repository.Found to occur in 3.3Found to occur in 3.7flutter/packages/flutter repository. See also f: labels.Relatively approachable for first-time contributorsThe issue has been confirmed reproducible and is ready to work onIssue is closed as already fixed in a newer versionOwned by Design Languages teamTriaged by Design Languages team