[Bug]: onConnectivityChanged returning old state not the state that it was changed to.

[aardrop]

Platform

iPhone 12

Plugin

connectivity_plus

Version

2.3.6 and 2.3.5

Flutter SDK

2.10.4

Steps to reproduce

I have wifi on my emulator turned on; when the connectivity is initialized it turnings a ConnectivityResult.none, and when I turn off wifi the listener returns a ConnectivityResult.wifi. This cycle persists regardless of the changes or order. So listening to the change is only returning the previous value not the new connectivity state.

Code Sample

import 'dart:async';
import 'dart:developer';

import 'package:connectivity_plus/connectivity_plus.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

class ConnectivityNotifier extends StateNotifier<ConnectivityResult> {
  ConnectivityNotifier() : super(ConnectivityResult.none) {
    initConnectivity();
    _connectivitySubscription =
        _connectivity.onConnectivityChanged.listen((data) {
      _updateConnectionStatus(data);
    });
  }

  final Connectivity _connectivity = Connectivity();
  late StreamSubscription<ConnectivityResult> _connectivitySubscription;

  Future<void> initConnectivity() async {
    late ConnectivityResult result;
    print('ConnectivityNotifier initConnectivity');
    try {
      result = await _connectivity.checkConnectivity();
    } on PlatformException catch (e) {
      log('ConnectivityNotifier Couldn\'t check connectivity status', error: e);
      return;
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) {
      return Future.value(null);
    }

    return _updateConnectionStatus(result);
  }

  Future<void> _updateConnectionStatus(ConnectivityResult result) async {
    print('ConnectivityNotifier._updateConnectionStatus: $result');
    state = result;
  }

  @override
  void dispose() {
    print('ConnectivityNotifier.dispose');
    _connectivitySubscription.cancel();
    super.dispose();
  }

  bool isConnected() {
    return state != ConnectivityResult.none;
  }
}

Logs

[   +1 ms] flutter: State variable after : ConnectivityResult.wifi
[+3767048 ms] flutter: State variable after : ConnectivityResult.wifi
[        ] flutter: connectivity from listener ConnectivityResult.wifi
[        ] flutter: ConnectivityNotifier._updateConnectionStatus: ConnectivityResult.wifi
[        ] flutter: State variable after : ConnectivityResult.wifi
[+12397 ms] flutter: State variable after : ConnectivityResult.wifi
[   +3 ms] flutter: connectivity from listener ConnectivityResult.none
[        ] flutter: ConnectivityNotifier._updateConnectionStatus: ConnectivityResult.none
[   +5 ms] flutter: State variable after : ConnectivityResult.none
[   +1 ms] flutter: State variable after : ConnectivityResult.none
[        ] flutter: connectivity from listener ConnectivityResult.none
[   +1 ms] flutter: ConnectivityNotifier._updateConnectionStatus: ConnectivityResult.none
[   +1 ms] flutter: State variable after : ConnectivityResult.none

Flutter Doctor

flutter doctor -v
[✓] Flutter (Channel unknown, 2.10.4, on macOS 12.4 21F79 darwin-arm, locale en-US)
    • Flutter version 2.10.4 at /Users/aaronkennedy/Development/flutter
    • Upstream repository unknown
    • Framework revision c860cba910 (4 months ago), 2022-03-25 00:23:12 -0500
    • Engine revision 57d3bac3dd
    • Dart version 2.16.2
    • DevTools version 2.9.2

[✗] Android toolchain - develop for Android devices
    ✗ Unable to locate Android SDK.
      Install Android Studio from: https://developer.android.com/studio/index.html
      On first launch it will assist you in installing the Android SDK components.
      (or visit https://flutter.dev/docs/get-started/install/macos#android-setup for detailed instructions).
      If the Android SDK has been installed to a custom location, please use
      `flutter config --android-sdk` to update to that location.


[✓] Xcode - develop for iOS and macOS (Xcode 13.4.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • CocoaPods version 1.11.3

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

[!] Android Studio (not installed)
    • Android Studio not found; download from https://developer.android.com/studio/index.html
      (or visit https://flutter.dev/docs/get-started/install/macos#android-setup for detailed instructions).

[✓] VS Code (version 1.69.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.44.0

[✓] Connected device (2 available)
    • iPhone 12 Pro (mobile) • DEDA0D01-91A3-47EB-A253-6C2F91DE0637 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-15-2 (simulator)
    • Chrome (web)           • chrome                               • web-javascript • Google Chrome 103.0.5060.114

[✓] HTTP Host Availability
    • All required HTTP hosts are available

! Doctor found issues in 2 categories.

[aardrop]

To clarify I also have this issue with the example app on emulator.

[galvanu]

I also have this issue, any suggested solution/workaround for this?

[miquelbeltran]

My guess is that the currentConnectivityType in this method is the old one when a new reachabilityChanged event is handled:

https://github.com/fluttercommunity/plus_plugins/blob/b206f0ae87972f55e1b3a81753c7512e6026c607/packages/connectivity_plus/connectivity_plus/macos/Classes/ReachabilityConnectivityProvider.swift#L57

and that's why it is giving the previous event all the time.

I don't know Swift enough to understand why it may be caching the previous value, but that would be my guess, if anyone wants to try to fix this:

https://github.com/fluttercommunity/plus_plugins/blob/b206f0ae87972f55e1b3a81753c7512e6026c607/packages/connectivity_plus/connectivity_plus/macos/Classes/ReachabilityConnectivityProvider.swift#L7

[github-actions[bot]]

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