Hi everybody,
  Could you help me solve this problem of showing nothing in listview.builder after a flutter web app released as shown in the next picture, although working well in the android release.
I tried to shorten city list but the problem still present
```
import 'package:admob_flutter/admob_flutter.dart';
import 'package:flutter/material.dart';
import 'package:flutter_native_admob/flutter_native_admob.dart';
import 'package:flutter_native_admob/native_admob_controller.dart';
import 'package:weather/conistants.dart';
import 'package:weather/service/ad_manager.dart';
import 'package:weather/service/networking.dart';
class SearchScreen extends StatefulWidget {
 @override
 _SearchScreenState createState() => _SearchScreenState();
}
class _SearchScreenState extends State<SearchScreen> {
 final _nativeAdController = NativeAdmobController();
 TextEditingController _controller = TextEditingController();
 dynamic cityWeatherData;
 bool isLoading = false;
 String cityName;
```
The list
```
 List cities = [
  City(city: 'Funafuti', lat: -8.5167, long: 179.2166),
  City(city: 'Palikir', lat: 6.9166, long: 158.15),
  City(city: 'Capitol Hill', lat: 15.2137, long: 145.7546),
  City(city: 'Hagta', lat: 13.4745, long: 144.7504),
  City(city: 'Al Quds', lat: 31.7764, long: 35.2269),
  City(city: 'Philipsburg', lat: 18.0255, long: -63.045),
  City(city: 'Gitega', lat: -3.4271, long: 29.9246),
  City(city: 'Pristina', lat: 42.6666, long: 21.1724),
  City(city: 'Ngerulmud', lat: 7.5, long: 134.6242),
 ];
```
The widgets
```
 List result = [];
 double cityLong;
 double cityLat;
 @override
 Widget build(BuildContext context) {
  return Scaffold(
   body: SingleChildScrollView(
    child: SafeArea(
     child: Container(
      decoration: BoxDecoration(
        image: DecorationImage(
          image: AssetImage('assets/images/city1.jpg'),
          fit: BoxFit.cover,
          colorFilter: ColorFilter.mode(
            Colors.black.withOpacity(.2), BlendMode.dstATop))),
      padding: EdgeInsets.all(15),
      child: Column(
       children: <Widget>[
        Container(
         height: 200,
         padding: EdgeInsets.all(10),
         margin: EdgeInsets.only(bottom: 20.0),
         child: NativeAdmob(
          // Your ad unit id
          adUnitID: _adUnitID,
          numberAds: 3,
          controller: _nativeAdController,
          type: NativeAdmobType.full,
         ),
        ),
        TextField(
         controller: _controller,
         decoration: InputDecoration(
          labelText: "Enter City...",
          prefixIcon: Icon(Icons.search),
          border: OutlineInputBorder(
           borderRadius: BorderRadius.all(
            Radius.circular(10),
           ),
          ),
         ),
         onChanged: (value) {
          setState(() {
           cityName = value;
          });
         },
        ),
        FlatButton(
          onPressed: () async {
           isLoading = true;
           if (cityWeatherData == null) {
            isLoading = true;
           } else {
            isLoading = false;
            Map<dynamic, dynamic> data = {
             'cityWeatherData': cityWeatherData,
             'cityName': cityName
            };
            Navigator.pop(context, data);
           }
          },
          child: Text(
           'Get Weather',
           style: KStatusTextStyle.copyWith(color: Colors.blue),
          )),
        Container(
         height: 470,
         child: Expanded(
          child: ListView.builder(
            itemCount: cities.length,
            itemBuilder: (context, index) {
             return cityName == null || cityName == ''
               ? null
               : cities[index]
                   .city
                   .toLowerCase()
                   .contains(cityName.toLowerCase())
                 ? Card(
                   color: Colors.transparent,
                   child: ListTile(
                    title: Text(cities[index].city),
                    onTap: () async {
                     setState(() {
                      _controller.text =
                        cities[index].city;
                      cityName = _controller.text;
                      print(cityName);
                      cityLong = cities[index].long;
                      cityLat = cities[index].lat;
                     });
                     CityNetworkHelper cityNetworkHelper =
                       CityNetworkHelper(
                         lat: cityLat, lon: cityLong);
                     cityWeatherData =
                       await cityNetworkHelper.getData();
                    },
                   ),
                  )
                 : new Container();
            }),
         ),
        ),
        AdmobBanner(
          adUnitId: AdManager.bannerAdUnitId,
          adSize: AdmobBannerSize.BANNER)
       ],
      ),
     ),
    ),
   ),
  );
 }
}
```
class City as shown
```
class City {
 final String city;
 final double long;
 final double lat;
 City({this.city, this.lat, this.long});
}
```