HTTP and JSON

flutter pub add http

// lib/models/post.dart
class Post {
  final int id;
  final String title;
  final String body;

  const Post({required this.id, required this.title, required this.body});

  factory Post.fromJson(Map<String, dynamic> json) => Post(
    id: json['id'] as int,
    title: json['title'] as String,
    body: json['body'] as String,
  );
}

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

class PostsScreen extends StatefulWidget {
  const PostsScreen({super.key});
  @override State<PostsScreen> createState() => _PostsScreenState();
}

class _PostsScreenState extends State<PostsScreen> {
  late Future<List<Post>> _posts;

  Future<List<Post>> _fetchPosts() async {
    final res = await http.get(
      Uri.parse('https://jsonplaceholder.typicode.com/posts?_limit=20'));
    if (res.statusCode != 200) throw Exception('Failed to load');
    final List data = jsonDecode(res.body);
    return data.map((j) => Post.fromJson(j)).toList();
  }

  @override
  void initState() { super.initState(); _posts = _fetchPosts(); }

  @override
  Widget build(BuildContext context) => Scaffold(
    appBar: AppBar(title: const Text('Posts')),
    body: FutureBuilder<List<Post>>(
      future: _posts,
      builder: (ctx, snap) {
        if (snap.connectionState == ConnectionState.waiting)
          return const Center(child: CircularProgressIndicator());
        if (snap.hasError)
          return Center(child: Text('Error: ${snap.error}'));
        return RefreshIndicator(
          onRefresh: () async { setState(() => _posts = _fetchPosts()); },
          child: ListView.builder(
            itemCount: snap.data!.length,
            itemBuilder: (_, i) => ListTile(
              title: Text(snap.data![i].title),
              subtitle: Text(snap.data![i].body, maxLines: 1,
                overflow: TextOverflow.ellipsis),
            ),
          ),
        );
      },
    ),
  );
}