I'm trying to Use data that I fetched from database and i got an error : "LateInitializationError: Field 'check' has not been initialized. " , i tried to remove the late word and adding " ? " and it gives another error "Expected a value of type 'num', but got one of type 'Null' "

class _letterssState extends State<letterss> {
  late var check;
  Future getData() async{
    var url = 'http://ip/getSpell.php';
    http.Response response = await http.get(Uri.parse(url));
    var data = jsonDecode(response.body);
    check=data;
    print(data.toString());

  }
  bool searchRes  (String s){
    int x=0;
    for ( var i=0 ; i<check.length;i   )
    {
      if (check[i]['letter']==s){
        x=i;
      }
    }
    if (check[x]['result']=='true')
    {
      return true;
    }
    else
    {
      return true;
    }
  }

  initState()
  {
    getData();
  }

CodePudding user response：

It will take some frame to get data from getData future method and assigning on check.

It would better to use FutureBuilder for future methods. Follow this doc example

 Future<List<yourDataType>?> getData() async {
    var url = 'http://ip/getSpell.php';
    http.Response response = await http.get(Uri.parse(url));
    var data = jsonDecode(response.body);
    return data;
  }
  late final future = getData();
  @override
  Widget build(BuildContext context) {
    return FutureBuilder<List<YourDataType>?>(
      future: future,
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          //todo:
        }
        return CircularProgressIndicator();
      },
    );
  }