Instance of list flutter

class Sale { int employeeId; double price; Sale(this.employeeId, this.price); } class Employee { int id; List sales; Employee (this.id, this.sales); } void main() { //Create a list of employees and their respective sales List employees = new List(); employees.add(new Employee(1, [new Sale(1, 100.50), new Sale(1, 300.25)])); employees.add(new Employee(2, [new Sale(2, 300.00), new Sale(2, 50.25), new Sale(2, 150.00)])); employees.add(new Employee(3, [new Sale(2, 400.00), new Sale(2, 30.75), new Sale(3, 50.00)])); //Sort so that the employee with the most sales is on top and so on... employees.sort((a, b) => (b.sales.fold(0, (prev, element) => prev + element.price)).compareTo(a.sales.fold(0, (prev, element) => prev + element.price))); log(employees); //prints Employee #2, followed by Employee #3, then ending with Employee #1 } void log(var lst) { lst.forEach((l) => print("Employee #${l.id} has ${l.sales.length} sales totaling ${l.sales.fold(0, (prev, element) => prev + element.price)} dollars!")); }

I'm new to flutter. I am getting an error like this, can you help me? I've been stuck in http for json for 5 days, the codes in the source don't work. :( L It says list not entered but when I enter it does not accept it. I don't know on which line the problem is, but I got a warning like. "The following NoSuchMethodError was thrown building FutureBuilder(dirty, state: _FutureBuilderState#447cc):" https://dosya.co/w8rxecrl44rz/Capture.JPG.html https://dosya.co/vk6rd85o7zkx/Capture.JPG2.JPG.html

1. import 'dart:convert';
2.  
3. Post postFromJson(String str) => Post.fromJson(json.decode(str));
4.  
5. String postToJson(Post data) => json.encode(data.toJson());
6.  
7. class Post {
8.   Post({
9.     required this.userId,
10.     required this.id,
11.     required this.title,
12.     required this.body,
13.   });
14.  
15.   int userId;
16.   int id;
17.   String title;
18.   String body;
19.  
20.   factory Post.fromJson(Map json) => Post(
21.     userId: json["userId"],
22.     id: json["id"],
23.     title: json["title"],
24.     body: json["body"],
25.   );
26.  
27.   Map toJson() => {
28.     "userId": userId,
29.     "id": id,
30.     "title": title,
31.     "body": body,
32.   };
33. }

1. import 'dart:convert';
2.  
3.  
4. import 'package:flutter/material.dart';
5. import 'package:http/http.dart' as http;
6. import 'package:json_http_place_holder/post.dart';
7.  
8. void main() {
9.   runApp(const MyApp());
10. }
11.  
12. class MyApp extends StatefulWidget {
13.   const MyApp({Key? key}) : super(key: key);
14.  
15.   @override
16.   State createState() => _MyAppState();
17. }
18.  
19. class _MyAppState extends State {
20.   Future getData = Future(() => null);
21.   var con = Uri.parse("https://jsonplaceholder.typicode.com/posts");
22.  
23.   Future> fetchPost() async {
24.     List result = [];
25.     final response = await http.get(con);
26.     if (response.statusCode == 200) {
27.       List listPost = jsonDecode(response.body);
28.       for (int i = 0; i < listPost.length; i++) {
29.         Post item = Post.fromJson(listPost[i]);
30.         result.add(item);
31.       }
32.     }
33.     return result;
34.   }
35.  
36.   @override
37.   void initState() {
38.     // TODO: implement initState
39.     super.initState();
40.     getData = fetchPost();
41.   }
42.  
43.   @override
44.   Widget build(BuildContext context) {
45.     return MaterialApp(
46.       title: 'Flutter HTTP json',
47.       theme: ThemeData(
48.         primarySwatch: Colors.blue,
49.       ),
50.       home: Scaffold(
51.         body: FutureBuilder(
52.           future: getData,
53.           builder: (BuildContext context,  AsyncSnapshot snapshot) {
54.             if (snapshot.connectionState == ConnectionState.waiting) {
55.               return const Center(
56.                 child: CircularProgressIndicator(),
57.               );
58.             } else if (snapshot.connectionState == ConnectionState.none) {
59.               return const Center(
60.                 child: Text("Bir hata meydana geldi"),
61.               );
62.             } else if (snapshot.connectionState == ConnectionState.done) {
63.               return ListView.separated(itemBuilder: (context,index){
64.                 return ListTile(
65.                   leading: Icon(Icons.local_post_office),
66.                   title: Text(snapshot.data[index].title),
67.                   subtitle: Text(snapshot.data[index].body),
68.                 );
69.               },separatorBuilder: (context,index)=>Divider(),
70.                 itemCount: snapshot.data.lenght,
71.               );
72.             }
73.             //var d =jsonDecode(snapshot.data.body);
74.             return Container();
75.           },
76.         ),
77.       ),
78.     );
79.   }
80. }