Riverpod Network Detection Example

network_detector_notifier.dart

import 'dart:async';

import 'package:connectivity/connectivity.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

enum NetworkStatus { NotDetermined, On, Off }

class NetworkDetectorNotifier extends StateNotifier<NetworkStatus> {
  StreamController<ConnectivityResult> controller =
      StreamController<ConnectivityResult>();

  NetworkStatus lastResult;

  NetworkDetectorNotifier() : super(NetworkStatus.NotDetermined) {
    lastResult = NetworkStatus.NotDetermined;
    Connectivity().onConnectivityChanged.listen((ConnectivityResult result) {
      // Use Connectivity() here to gather more info if you need t
      NetworkStatus newState;
      switch (result) {
        case ConnectivityResult.mobile:
        case ConnectivityResult.wifi:
          newState = NetworkStatus.On;
          break;
        case ConnectivityResult.none:
          newState = NetworkStatus.Off;
          // TODO: Handle this case.
          break;
      }

      if (newState != state) {
        state = newState;
      }
    });
  }
}

final networkAwareProvider = StateNotifierProvider((ref) {
  return NetworkDetectorNotifier();
});

your_screen.dart

class YourScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Consumer(builder: (context, watch, child) {
      var network = watch(networkAwareProvider).state;
      if (network == NetworkStatus.Off) {
        return Center(child: Text("No network"));
      }

      return Container(child: Text("Normal stuff"));
    });
  }
}

@pishguy
From official Riverpod documentation
Depending on the provider used, it may already take care of the clean-up process. For example, StateNotifierProvider will call the dispose method of a StateNotifier.

So, In NetworkDetectorNotifier we can add:

@override
  void dispose() {
    super.dispose();
    subscription.cancel();
  }

and provider should be:

  final networkAwareProvider = StateNotifierProvider.autoDispose<NetworkDetectorNotifier, NetworkStatus>((ref) {
  return NetworkDetectorNotifier();
});

@AErmek Thanks so much :) , let me try