Flutter list async error return from JSON

Question

I watched this tutorial but im stuck in return of future list https://www.youtube.com/watch?v=lTKFYGHx16M trying to connect mysql php api and flutter code

import '../model/usersdata.dart';
import 'package:http/http.dart' as http;

Future<List<Userprofile>> fetchUsers() async {
  var url = Uri.parse("http://192.168.100.68/mlm_sys/api_request/get_data.php");
  final response = await http.get(url);
  print(response.body);
  return userprofileFromJson(response.body);<----ERROR LINE

ERROR: //A value of type 'Userprofile' can't be returned from the function 'fetchUsers' because it has a return type of 'Future<List>'. }

///=====MODEL

import 'dart:convert';

Userprofile userprofileFromJson(String str) =>
    Userprofile.fromJson(json.decode(str));

String userprofileToJson(Userprofile data) => json.encode(data.toJson());

class Userprofile {
  Userprofile({
    required this.id,
    required this.sponsor,
    required this.fname,
    required this.lname,
    required this.mname,
    required this.pnum,
    required this.address,
    required this.email,
    required this.username,
    required this.password,
    required this.dateRegistration,
  });

........AND SO ON

Userprofile is not a List of Userprofile... you need to map your response and turn into a list — Mariano Zorrilla
– Mariano Zorrilla, Commented Aug 24, 2021 at 20:08
@MarianoZorrilla i have map in my model is this what you means? Map<String, dynamic> toJson() => { "id": id, "sponsor": sponsor, "fname": fname, "lname": lname, "mname": mname, "pnum": pnum, "address": address, "email": email, "username": username, "password": password, "date_registration": "${dateRegistration.year.toString().padLeft(4, '0')}-${dateRegistration.month.toString().padLeft(2, '0')}-${dateRegistration.day.toString().padLeft(2, '0')}", }; — Jedd Mercado
– Jedd Mercado, Commented Aug 24, 2021 at 20:18

Giacomo1968 · Accepted Answer · 2021-08-26 16:03:49Z

2

The fetchUsers() is expected to return a list of user profiles, but the function userprofileFromJson() returns only a user profile object. You may update the fetch users function to be like this (considering the response.body is a list of user profiles).

Future<List<Userprofile>> fetchUsers() async {
    var url = Uri.parse("http://192.168.100.68/mlm_sys/api_request/get_data.php");
    final http.Response response = await http.get(url);
    print(response.body);
    /********* the return statement needs to be like this ******/
    return List<Userprofile>.from(
        (json.decode(response.body) as List).map((jsonString) => userprofileFromJson(jsonString)));
  }

edited Aug 26, 2021 at 16:03

Giacomo1968

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answered Aug 24, 2021 at 21:20

Emad Adly

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1 Comment

Jedd Mercado Over a year ago

Okay iget it now. Thank you so much

magic · Accepted Answer · 2021-08-24 20:39:55Z

Your method called userprofileFromJson returns a map, not a list. You should use this converter to create this UserProfile class agait. You can copy a sample json file that your server sends and paste it. After that, you can copy the finished dart code and paste it instead of your code. Finally, type await between return and the returned value like this:

Future<List<Userprofile>> fetchUsers() async {
  var url = Uri.parse("http://192.168.100.68/mlm_sys/api_request/get_data.php");
  final response = await http.get(url);
  print(response.body);
  return await userprofileFromJson(response.body);

The difference is that you don't return a future with await. You return the real value after it arrives.

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