How to get data from url Json array in flutter?

Question

I have just started programming with flutter, and tried to retrieve the time,icon and temp variables from the following file, so far, without success I would welcome any help you could offer.

class Hourly {
  String time;
  String icon;
  int temp;

  Hourly({this.time, this.icon, this.temp});
}

class Network {
  String url = "************";
  List<Hourly> hourly = [];

  Future<List<Hourly>> fetchHourly() async {
    final res = await http.get(url, headers: {"Accept": "aplication/json"});
    final jsonData = json.decode(res.body);
final hourly = jsonData['hourly'];
final data = hourly['data'];
    for (var h in data) {
      Hourly hour =
          new Hourly(time: h['time'], icon: h['icon'], temp: h['temperature']);
      hourly.add(hour);
    }
    if (res.statusCode == 200) {
      return hourly;
    }
  }
}

and fetch data here ..

  FutureBuilder( future: Network.fetchHourly(), builder: (BuildContext context, AsyncSnapshot snap) { return ListView.builder( itemCount: snap.data.length, itemBuilder: (BuildContext context, int i) { return new HourlyItem(snap.data[i].icon, snap.data[i].time, snap.data[i].temp); }, ); }, ), 

Error

NoSuchMethodError: The getter 'length' was called on null.

Answer 1

I think your forgot to get your hourly object before data array.

 final hourly = jsonData['hourly'];
 final data = hourly['data'];

should work

Ok few changes:

Change the type of your fields :

  class Hourly {
    int time;
    String icon;
    String temp;

    Hourly({this.time, this.icon, this.temp});
  }

And update your method to return cast temp to String

    Future<List<Hourly>> fetchHourly() async {
        final res = await http.get(url, headers: {"Accept": "aplication/json"});
        final jsonData = json.decode(res.body);
        final dataHourly = jsonData['hourly'];
        final data = dataHourly['data'];
        for (var h in data) {
          Hourly hour =
              new Hourly(time: h['time'], icon: h['icon'], temp: h['temperature'].toString());
          hourly.add(hour);
        }
        if (res.statusCode == 200) {
          return hourly;
        }
      }

Your code fixed:

https://gist.github.com/diegoveloper/c53b4a3158f2ed710a089a830ed2e4b5