Flutter — готовые виджеты — Загрузка списка с API

import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(home: const UsersScreen());
  }
}

class UsersScreen extends StatefulWidget {
  const UsersScreen({super.key});

  @override
  State<UsersScreen> createState() => _UsersScreenState();
}

class _UsersScreenState extends State<UsersScreen> {
  late Future<List<String>> _future;

  @override
  void initState() {
    super.initState();
    _future = _loadUsers();
  }

  Future<List<String>> _loadUsers() async {
    final uri = Uri.parse('https://jsonplaceholder.typicode.com/users');
    final response = await http.get(uri);
    if (response.statusCode != 200) {
      throw Exception('Ошибка сервера: ${response.statusCode}');
    }
    final data = jsonDecode(response.body) as List;
    return data.map((u) => u['name'] as String).toList();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Пользователи')),
      body: FutureBuilder<List<String>>(
        future: _future,
        builder: (context, snapshot) {
          if (snapshot.connectionState == ConnectionState.waiting) {
            return const Center(child: CircularProgressIndicator());
          }
          if (snapshot.hasError) {
            return Center(
              child: Padding(
                padding: const EdgeInsets.all(16),
                child: Text('Ошибка: ${snapshot.error}'),
              ),
            );
          }
          final items = snapshot.data ?? [];
          if (items.isEmpty) {
            return const Center(child: Text('Список пуст'));
          }
          return ListView.builder(
            itemCount: items.length,
            itemBuilder: (_, i) => ListTile(
              leading: const Icon(Icons.person_outline),
              title: Text(items[i]),
            ),
          );
        },
      ),
    );
  }
}