Flutter Plugin for Discovering The State Of The Network Connectivity

connectivity_plus 

This plugin allows Flutter apps to discover network connectivity and configure themselves accordingly. It can distinguish between cellular vs WiFi connection.

Note

On Android, this does not guarantee connection to Internet. For instance, the app might have wifi access but it might be a VPN or a hotel WiFi > with no access.

Platform Support 

Usage 

Sample usage to check current status:

import 'package:connectivity_plus/connectivity_plus.dart';

final connectivityResult = await (Connectivity().checkConnectivity());
if (connectivityResult == ConnectivityResult.mobile) {
  // I am connected to a mobile network.
} else if (connectivityResult == ConnectivityResult.wifi) {
  // I am connected to a wifi network.
} else if (connectivityResult == ConnectivityResult.ethernet) {
  // I am connected to a ethernet network.
} else if (connectivityResult == ConnectivityResult.vpn) {
  // I am connected to a vpn network.
  // Note for iOS and macOS:
  // There is no separate network interface type for [vpn].
  // It returns [other] on any device (also simulator)
} else if (connectivityResult == ConnectivityResult.bluetooth) {
  // I am connected to a bluetooth.
} else if (connectivityResult == ConnectivityResult.other) {
  // I am connected to a network which is not in the above mentioned networks.
} else if (connectivityResult == ConnectivityResult.none) {
  // I am not connected to any network.
}

Note

You should not be using the current network status for deciding whether you can reliably make a network connection. Always guard your app code against timeouts and errors that might come from the network layer.

You can also listen for network state changes by subscribing to the stream exposed by connectivity plugin:

import 'package:connectivity_plus/connectivity_plus.dart';

@override
initState() {
  super.initState();

  subscription = Connectivity().onConnectivityChanged.listen((ConnectivityResult result) {
    // Got a new connectivity status!
  });
}

// Be sure to cancel subscription after you are done
@override
dispose() {
  subscription.cancel();
  super.dispose();
}

Note

Connectivity changes are no longer communicated to Android apps in the background starting with Android O (8.0). You should always check for connectivity status when your app is resumed. The broadcast is only useful when your application is in the foreground.

Limitations on the web platform 

In order to retrieve information about the quality/speed of a browser's connection, the web implementation of the connectivity plugin uses the browser's NetworkInformation Web API, which as of this writing (June 2020) is still "experimental", and not available in all browsers:

On desktop browsers, this API only returns a very broad set of connectivity statuses (One of 'slow-2g', '2g', '3g', or '4g'), and may not provide a Stream of changes. Firefox still hasn't enabled this feature by default.

Fallback to navigator.onLine

For those browsers where the NetworkInformation Web API is not available, the plugin falls back to the NavigatorOnLine Web API, which is more broadly supported:

The NavigatorOnLine API is provided by dart:html, and only supports a boolean connectivity status (either online or offline), with no network speed information. In those cases the plugin will return either wifi (when the browser is online) or none (when it's not).

Other than the approximate "downlink" speed, where available, and due to security and privacy concerns, no Web browser will provide any specific information about the actual network your users' device is connected to, like the SSID on a Wi-Fi, or the MAC address of their device.

Learn more 

• API Documentation
• Plugin documentation website

Use this package as a library

Depend on it

Run this command:

With Flutter:

 $ flutter pub add connectivity_plus

This will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):

dependencies:
  connectivity_plus: ^5.0.1

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:connectivity_plus/connectivity_plus.dart';

example/lib/main.dart

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// ignore_for_file: public_member_api_docs

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

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

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        useMaterial3: true,
        colorSchemeSeed: const Color(0x9f4376f8),
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  ConnectivityResult _connectionStatus = ConnectivityResult.none;
  final Connectivity _connectivity = Connectivity();
  late StreamSubscription<ConnectivityResult> _connectivitySubscription;

  @override
  void initState() {
    super.initState();
    initConnectivity();

    _connectivitySubscription =
        _connectivity.onConnectivityChanged.listen(_updateConnectionStatus);
  }

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

  // Platform messages are asynchronous, so we initialize in an async method.
  Future<void> initConnectivity() async {
    late ConnectivityResult result;
    // Platform messages may fail, so we use a try/catch PlatformException.
    try {
      result = await _connectivity.checkConnectivity();
    } on PlatformException catch (e) {
      developer.log('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 {
    setState(() {
      _connectionStatus = result;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Connectivity example app'),
        elevation: 4,
      ),
      body: Center(
          child: Text('Connection Status: ${_connectionStatus.toString()}')),
    );
  }
}

Download details:

Author: fluttercommunity.dev
 Source: https://github.com/fluttercommunity/plus_plugins/tree/main/packages/connectivity_plus/connectivity_plus

#flutter #android #ios