Navigator 2.0 pop callbacks not working

[shovelmn12]

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

Trying to implement Navigator 2.0 and back button callbacks are not working.

MyRouterDelegate.popRoute() and MyBackButtonDispatcher.invokeCallback() are not being called

Code Sample provided

Expected results

call provided pop callbacks

Actual results

app closes

Code sample

Code sample

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

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

  @override
  Widget build(BuildContext context) => MaterialApp.router(
        routerConfig: RouterConfig<String>(
          routerDelegate: MyRouterDelegate(),
          backButtonDispatcher: MyBackButtonDispatcher(),
          routeInformationParser: const MyRouteInformationParser(),
          routeInformationProvider: MyRouteInformationProvider(),
        ),
      );
}

void main() => runApp(const MyApp());

class MyRouteInformationParser extends RouteInformationParser<String> {
  const MyRouteInformationParser() : super();

  @override
  SynchronousFuture<String> parseRouteInformation(
    RouteInformation routeInformation,
  ) =>
      SynchronousFuture("${routeInformation.uri}");

  @override
  RouteInformation restoreRouteInformation(String uri) => RouteInformation(
        uri: Uri.parse(uri),
      );
}

class MyBackButtonDispatcher extends BackButtonDispatcher {
  @override
  Future<bool> invokeCallback(Future<bool> defaultValue) async {
    print("MyBackButtonDispatcher.invokeCallback");

    return false;
  }
}

class MyRouterDelegate extends RouterDelegate<String> with ChangeNotifier {
  @override
  Widget build(BuildContext context) => const Scaffold(
        body: Center(
          child: Text("Pop Test"),
        ),
      );

  @override
  Future<bool> popRoute() async {
    print("popRoute");

    return false;
  }

  @override
  Future<void> setNewRoutePath(String configuration) async {}
}

class MyRouteInformationProvider extends RouteInformationProvider
    with ChangeNotifier {
  @override
  RouteInformation get value => RouteInformation(
        uri: Uri(),
      );
}

Screenshots or Video

Screenshots / Video demonstration

Screen.Recording.2023-09-19.at.12.08.24.mp4

and as you can see no prints:

Screen.Recording.2023-09-19.at.12.09.17.mp4

Logs

Logs

[Paste your logs here]

Flutter Doctor output

Doctor output

[✓] Flutter (Channel stable, 3.13.4, on macOS 13.5.2 22G91 darwin-x64, locale en-NO)
    • Flutter version 3.13.4 on channel stable at /Users/username/fvm/versions/3.13.4
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 367f9ea16b (6 days ago), 2023-09-12 23:27:53 -0500
    • Engine revision 9064459a8b
    • Dart version 3.1.2
    • DevTools version 2.25.0

[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
    • Android SDK at /Users/username/Library/Android/sdk
    • Platform android-34, build-tools 34.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b829.9-10027231)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 14.3.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 14E300c
    • CocoaPods version 1.12.1

[✓] Android Studio (version 2022.3)
    • 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+0-17.0.6b829.9-10027231)

[✓] IntelliJ IDEA Ultimate Edition (version 2023.2.1)
    • IntelliJ at /Applications/IntelliJ IDEA.app
    • 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

[✓] IntelliJ IDEA Community Edition (version 2023.2.1)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • 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 1.82.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.72.0

[✓] Connected device (1 available)
    • sdk gphone64 x86 64 (mobile) • emulator-5554 • android-x64 • Android 13 (API 33) (emulator)

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

• No issues found!

[dam-ease]

Thanks for filing this. I can reproduce this on the latest master and stable channels as described above.

Log

Connecting to VM Service at ws://127.0.0.1:55045/4fgxdcuwksI=/ws
D/ProfileInstaller(17047): Installing profile for com.example.master
I/.example.master(17047): Background concurrent copying GC freed 61825(2866KB) AllocSpace objects, 3(60KB) LOS objects, 49% free, 2618KB/5236KB, paused 385us,13us total 129.230ms
D/EGL_emulation(17047): app_time_stats: avg=14785.31ms min=94.44ms max=43923.70ms count=3
W/WindowOnBackDispatcher(17047): sendCancelIfRunning: isInProgress=falsecallback=android.view.ViewRootImpl$$ExternalSyntheticLambda17@133eeb7

stable, master flutter doctor -v

[✓] Flutter (Channel stable, 3.13.4, on macOS 13.0 22A380 darwin-arm64, locale
    en-NG)
    • Flutter version 3.13.4 on channel stable at
      /Users/damilolaalimi/sdks/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 367f9ea16b (5 days ago), 2023-09-12 23:27:53 -0500
    • Engine revision 9064459a8b
    • Dart version 3.1.2
    • DevTools version 2.25.0

[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
    • Android SDK at /Users/damilolaalimi/Library/Android/sdk
    • Platform android-34, build-tools 34.0.0
    • ANDROID_HOME = /Users/damilolaalimi/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 14.3.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 14E300c
    • CocoaPods version 1.12.1

[✓] 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 1.82.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.50.0

[✓] Connected device (3 available)
    • iPhone 14 Pro Max (mobile) • BB55E997-7F31-462D-B3B1-6B177D9B40C7 • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-16-4 (simulator)
    • macOS (desktop)            • macos                                •
      darwin-arm64   • macOS 13.0 22A380 darwin-arm64
    • Chrome (web)               • chrome                               •
      web-javascript • Google Chrome 116.0.5845.187

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

• No issues found!

[✓] Flutter (Channel master, 3.14.0-14.0.pre.358, on macOS 13.0 22A380 darwin-arm64, locale en-NG)
    • Flutter version 3.14.0-14.0.pre.358 on channel master at /Users/damilolaalimi/fvm/versions/master
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 8936504163 (3 hours ago), 2023-09-19 02:10:24 -0400
    • Engine revision 589bde9a95
    • Dart version 3.2.0 (build 3.2.0-174.0.dev)
    • DevTools version 2.28.0-dev.8

[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
    • Android SDK at /Users/damilolaalimi/Library/Android/sdk
    • Platform android-34, build-tools 34.0.0
    • ANDROID_HOME = /Users/damilolaalimi/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 14.3.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 14E300c
    • CocoaPods version 1.12.1

[✓] 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 1.82.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.50.0

[✓] Connected device (4 available)
    • sdk gphone64 arm64 (mobile) • emulator-5554                        • android-arm64  • Android 14 (API 34) (emulator)
    • iPhone 14 Pro Max (mobile)  • BB55E997-7F31-462D-B3B1-6B177D9B40C7 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-16-4 (simulator)
    • macOS (desktop)             • macos                                • darwin-arm64   • macOS 13.0 22A380 darwin-arm64
    • Chrome (web)                • chrome                               • web-javascript • Google Chrome 116.0.5845.187

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

• No issues found!

[shovelmn12]

I must say, even though I love flutter, navigation in flutter is just horrible ! With nav 2.0 there is a mess of using Navigator with router libraries, as flutter it self uses Navigator (e.g. Overlays) and devs use router libraries

Why can't it be simplified? Just a thought, I might be missing details here:

As I see it we have different platforms and each of them should provide us with routes (initial route and push route from deep link or url change etc ...). On top of that we need to provide the platform whats the current route (ex. for web). This is the interface between flutter and the platform it is running on. Also we will need a callback for pop.

based on my thoughts:

abstract class Router<T> extends StatefulWidget {
  @override
  State<Rotuer<T>> createState();
}

abstract class RouterState<T> extends State<Router<T>> {
  String get path // platform will listen to RouterState and will fetch updated path from this field

  void onPathProvided(String path) // set app to this route
  
  void pop([dynamic result]) // shouldn't be different from Route's actual pop function
}

Now the part that I dont really understand is the need for Navigator, I mean I see it's used for overlays but it's NOT the only way to go about this.

I'd like to see what react have:

Widget build(BuildContext context) =>
  MaterialApp(
    child: SomeNavigationLibrary(
      // whatever navigation library implementation
    )
  )

That way the sky is the limit for different navigation styles, also it can follows up on flutter's style of writing, everything is a widget (well not really at the moment):

Widget build(BuildContext context) =>
  MaterialApp(
    child: SomeNavigationLibrary(
      routes: {
        if (!context.isLoggedIn)
        "/auth":  (context) => const AuthWidget(),
        if (!context.isLoggedIn)
        ".*": (context) => const Redirect("/auth"),
        if (context.isLoggedIn)
        "/home": (context) => const HomeWidget(),
        if (context.isLoggedIn)
        ".*": (context) => const Redirect("/home"),
        "/help" (context) => const HelpWidget(),
        ".*/about": (context) => const AboutDialog(), // will display about dialog anywhere in the app as long as path ends with "/about"
      }
    )
  )

I think if it's possible to achive it will simplify flutter's navigation and will also decouple navigation from WidgetsApp.

[goderbauer]

cc @chunhtai

[shovelmn12]

Any news ?

[chunhtai]

The issue is the backbutton dispatcher. Either you need to register itself with widgetbindingobserver to listen of didpopRoute, or extends RootBackButtonDispatcher