在 dart、flutter 应用程序中检查或连续收听 Internet 连接/网络连接

Question

I have been searching for long to know the best approach to listen to internet connection in flutter/dart app. I think this approach is better for now and it can be of help to some like me who has been searching. I have used many connectivity plugins, but it didn't work. I have equally used data_connection_checker, lookUpAddress etc as suggested by many but to no avail. But below helped. Use the below plugins to check or listen to Internet Connection / Network Connectivity in dart, flutter app.

connectivity_plus

internet_connection_checker

import 'dart:async';
import 'package:connectivity_plus/connectivity_plus.dart';
import 'package:internet_connection_checker/internet_connection_checker.dart';

class ConnectionUtil {
  static final ConnectionUtil _singleton = new ConnectionUtil._internal();
  ConnectionUtil._internal();

  static ConnectionUtil getInstance() => _singleton;

  bool hasConnection = false;

  StreamController connectionChangeController = StreamController();

  final Connectivity _connectivity = Connectivity();
  void initialize() {
    _connectivity.onConnectivityChanged.listen(_connectionChange);
  }

  void _connectionChange(ConnectivityResult result) {
    _hasInternetInternetConnection();
  }

  Stream get connectionChange => connectionChangeController.stream;
  Future<bool> _hasInternetInternetConnection() async {
    bool previousConnection = hasConnection;
    var connectivityResult = await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.mobile || connectivityResult == ConnectivityResult.wifi) {
      // this is the different
      if (await InternetConnectionChecker().hasConnection) {
        hasConnection = true;
      } else {
        hasConnection = false;
      }
    } else {
      hasConnection = false;
    }

    if (previousConnection != hasConnection) {
      connectionChangeController.add(hasConnection);
    }
    return hasConnection;
  }
}

Implement this code on the stateful widget.....

  bool hasInterNetConnection = false;

  @override
  initState() {
    ConnectionUtil connectionStatus = ConnectionUtil.getInstance();
    connectionStatus.initialize();
    connectionStatus.connectionChange.listen(connectionChanged);

    super.initState();
  }

  void connectionChanged(dynamic hasConnection) {
    setState(() {
      hasInterNetConnection = hasConnection;
    });
  }

Good luck

Answer 1

I had faced a similar problem a few weeks ago. This is a good approach. The internet_connection_checker plugin allows one to address issues at the network layer that the connectivity_plus plugin cannot address. I have carried out an implementation of these two plugins using the bloc library. For more information and code refer to this Stackoverflow post and this Github issue.