import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  int _counter = 0;
  List<String> _items = [];

  void _incrementCounter() {
    setState(() {
      _counter++;
      _items.add('Item $_counter');
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter App'),
        elevation: 0,
      ),
      body: Column(
        children: [
          Container(
            padding: EdgeInsets.all(20),
            child: Text(
              'You have pushed the button $_counter times:',
              style: Theme.of(context).textTheme.headline6,
            ),
          ),
          Expanded(
            child: ListView.builder(
              itemCount: _items.length,
              itemBuilder: (context, index) {
                return Card(
                  margin: EdgeInsets.symmetric(horizontal: 16, vertical: 4),
                  child: ListTile(
                    leading: CircleAvatar(
                      child: Text('1'),
                    ),
                    title: Text(_items[index]),
                    trailing: IconButton(
                      icon: Icon(Icons.delete),
                      onPressed: () {
                        setState(() {
                          _items.removeAt(index);
                        });
                      },
                    ),
                  ),
                );
              },
            ),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

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

class ApiService {
  static const String baseUrl = 'https://api.example.com';
  
  static Future<List<User>> getUsers() async {
    try {
      final response = await http.get(
        Uri.parse('$baseUrl/users'),
        headers: {'Content-Type': 'application/json'},
      );
      
      if (response.statusCode == 200) {
        List<dynamic> jsonData = json.decode(response.body);
        return jsonData.map((json) => User.fromJson(json)).toList();
      } else {
        throw Exception('Failed to load users');
      }
    } catch (e) {
      throw Exception('Network error: $e');
    }
  }
  
  static Future<User> createUser(User user) async {
    final response = await http.post(
      Uri.parse('$baseUrl/users'),
      headers: {'Content-Type': 'application/json'},
      body: json.encode(user.toJson()),
    );
    
    if (response.statusCode == 201) {
      return User.fromJson(json.decode(response.body));
    } else {
      throw Exception('Failed to create user');
    }
  }
}

class User {
  final int id;
  final String name;
  final String email;
  
  User({required this.id, required this.name, required this.email});
  
  factory User.fromJson(Map<String, dynamic> json) {
    return User(
      id: json['id'],
      name: json['name'],
      email: json['email'],
    );
  }
  
  Map<String, dynamic> toJson() {
    return {
      'id': id,
      'name': name,
      'email': email,
    };
  }
}

import 'package:flutter/foundation.dart';
import 'package:provider/provider.dart';

class UserProvider with ChangeNotifier {
  List<User> _users = [];
  bool _isLoading = false;
  String? _error;

  List<User> get users => _users;
  bool get isLoading => _isLoading;
  String? get error => _error;

  Future<void> fetchUsers() async {
    _isLoading = true;
    _error = null;
    notifyListeners();

    try {
      _users = await ApiService.getUsers();
    } catch (e) {
      _error = e.toString();
    } finally {
      _isLoading = false;
      notifyListeners();
    }
  }

  Future<void> addUser(User user) async {
    try {
      final newUser = await ApiService.createUser(user);
      _users.add(newUser);
      notifyListeners();
    } catch (e) {
      _error = e.toString();
      notifyListeners();
    }
  }
}

// Usage in widget
class UserListPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Users')),
      body: Consumer<UserProvider>(
        builder: (context, userProvider, child) {
          if (userProvider.isLoading) {
            return Center(child: CircularProgressIndicator());
          }
          
          if (userProvider.error != null) {
            return Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Text('Error: '),
                  ElevatedButton(
                    onPressed: () => userProvider.fetchUsers(),
                    child: Text('Retry'),
                  ),
                ],
              ),
            );
          }
          
          return ListView.builder(
            itemCount: userProvider.users.length,
            itemBuilder: (context, index) {
              final user = userProvider.users[index];
              return ListTile(
                title: Text(user.name),
                subtitle: Text(user.email),
              );
            },
          );
        },
      ),
    );
  }
}