manage connectivity in flutter

connectivity.dart

import 'dart.io'; //use this 

bool connected=false; // and define this global variable.

 Future<bool> _checkConnectivity() async {
    bool connect;
    try {
      final result = await InternetAddress.lookup('google.com');
      if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
        connect = true;
      }
    } on SocketException catch (_) {
      connect = false;
    }
    return connect;
  }

 @override
  Widget build(BuildContext context) {
    height = MediaQuery.of(context).size.height;
    width = MediaQuery.of(context).size.width;
    _checkConnectivity().then((internet) {
      setState(() {
        connected = internet;
      });
    });
    return new Scaffold(
      //use that boolean here.
    body:connected? Listview() : noInternetImage():
    );
    
  }