Connectivity Demo

connectivitydemo.dart

import 'dart:async';

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Network state demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('NetworkState Demo'),
      ),
      body: FormWidget(),
    );
  }
}

class FormWidget extends StatefulWidget {
  @override
  _FormWidgetState createState() => _FormWidgetState();
}

class _FormWidgetState extends State<FormWidget> {
  String assetUrl = "assets/wifi.gif";
  String message = "Unknown Connection";
  StreamSubscription subscription;

  @override
  void initState() {
    super.initState();
    subscription = Connectivity()
        .onConnectivityChanged
        .listen((ConnectivityResult result) {
      if (result == ConnectivityResult.none) {
        setState(() {
          assetUrl = "assets/no_wifi.gif";
          message = "No network connection";
        });
      }
      if (result == ConnectivityResult.mobile) {
        setState(() {
          assetUrl = "assets/network.gif";
          message = "Mobile network connected";
        });
      } else if (result == ConnectivityResult.wifi) {
        setState(() {
          assetUrl = "assets/wifi.gif";
          message = "Wifi Connected";
        });
      }
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return Form(
      child: Column(
        children: <Widget>[
          Image.asset(assetUrl,height: 200,),
          Text(
            message,
            style: TextStyle(fontSize: 30, fontWeight: FontWeight.w700),
          ),
          Image.network("https://pbs.twimg.com/media/EcUEf3oUcAAshqn?format=jpg&name=medium"),
        ],
      ),
    );
  }
}