RouteObserver example throws an error #141078
Description
Steps to reproduce
Paste the sample code found on the RouteObserver documentation page into your IDE and attempt to run it (tested on Windows, web, and Android).
Expected results
The code runs normally.
Actual results
The application loads a red error screen with the message:
======== Exception caught by widgets library =======================================================
The following assertion was thrown building _FocusInheritedScope:
A GlobalKey was used multiple times inside one widget's child list.
The offending GlobalKey was: [GlobalObjectKey<NavigatorState> _WidgetsAppState#f9d32]
The parent of the widgets with that key was: _FocusInheritedScope
The first child to get instantiated with that key became: Navigator-[GlobalObjectKey<NavigatorState> _WidgetsAppState#f9d32]
dirty
state: NavigatorState#d69af(lifecycle state: created)
The second child that was to be instantiated with that key was: _FocusInheritedScope
A GlobalKey can only be specified on one widget at a time in the widget tree.
Code sample
Code sample
// Register the RouteObserver as a navigation observer.
import 'package:flutter/material.dart';
final RouteObserver<ModalRoute<void>> routeObserver = RouteObserver<ModalRoute<void>>();
void main() {
runApp(MaterialApp(
home: Container(),
navigatorObservers: <RouteObserver<ModalRoute<void>>>[ routeObserver ],
));
}
class RouteAwareWidget extends StatefulWidget {
const RouteAwareWidget({super.key});
@override
State<RouteAwareWidget> createState() => RouteAwareWidgetState();
}
// Implement RouteAware in a widget's state and subscribe it to the RouteObserver.
class RouteAwareWidgetState extends State<RouteAwareWidget> with RouteAware {
@override
void didChangeDependencies() {
super.didChangeDependencies();
routeObserver.subscribe(this, ModalRoute.of(context)!);
}
@override
void dispose() {
routeObserver.unsubscribe(this);
super.dispose();
}
@override
void didPush() {
// Route was pushed onto navigator and is now topmost route.
}
@override
void didPopNext() {
// Covering route was popped off the navigator.
}
@override
Widget build(BuildContext context) => Container();
}Screenshots or Video
Screenshots / Video demonstration
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Logs
Logs
[Paste your logs here]Flutter Doctor output
Doctor output
[√] Flutter (Channel stable, 3.16.5, on Microsoft Windows [Version 10.0.19045.3803], locale en-US)
• Flutter version 3.16.5 on channel stable at C:\Development\flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 78666c8dc5 (3 weeks ago), 2023-12-19 16:14:14 -0800
• Engine revision 3f3e560236
• Dart version 3.2.3
• DevTools version 2.28.4
[√] Windows Version (Installed version of Windows is version 10 or higher)
[√] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
• Android SDK at C:\Users\Matt\AppData\Local\Android\sdk
• Platform android-34, build-tools 34.0.0
• Java binary at: C:\Users\Matt\AppData\Local\Programs\Android Studio\jbr\bin\java
• Java version OpenJDK Runtime Environment (build 17.0.7+0-b2043.56-10550314)
• All Android licenses accepted.
[√] Chrome - develop for the web
• Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe
[√] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.6.5)
• Visual Studio at C:\Program Files\Microsoft Visual Studio\2022\Community
• Visual Studio Community 2022 version 17.6.33829.357
• Windows 10 SDK version 10.0.22000.0
[√] Android Studio (version 2023.1)
• Android Studio at C:\Users\Matt\AppData\Local\Programs\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 17.0.7+0-b2043.56-10550314)
[√] IntelliJ IDEA Ultimate Edition (version 2023.1)
• IntelliJ at C:\Users\Matt\AppData\Local\Programs\IntelliJ IDEA Ultimate
• 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 1.79.2)
• VS Code at C:\Users\Matt\AppData\Local\Programs\Microsoft VS Code
• Flutter extension can be installed from:
https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter
[√] Connected device (4 available)
• Android SDK built for x86 (mobile) • emulator-5554 • android-x86 • Android 8.1.0 (API 27) (emulator)
• Windows (desktop) • windows • windows-x64 • Microsoft Windows [Version 10.0.19045.3803]
• Chrome (web) • chrome • web-javascript • Google Chrome 120.0.6099.130
• Edge (web) • edge • web-javascript • Microsoft Edge 120.0.2210.121
[√] Network resources
• All expected network resources are available.
• No issues found!Metadata
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Stack traces logged to the consoleSample code and demosNavigator, Router, and related APIs.Found to occur in 3.16Found to occur in 3.18flutter/packages/flutter repository. See also f: labels.The issue has been confirmed reproducible and is ready to work onIssue is closed as already fixed in a newer versionOwned by Framework team
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