Generate UUID in Flutter

import 'package:uuid/uuid.dart';

const uuid = Uuid();
final id = uuid.v4();
print(id); // → "550e8400-e29b-41d4-a716-446655440000"

import 'package:hive/hive.dart';
import 'package:uuid/uuid.dart';

const _uuid = Uuid();

part 'note.g.dart';

@HiveType(typeId: 0)
class Note extends HiveObject {
  @HiveField(0)
  final String id;

  @HiveField(1)
  String title;

  @HiveField(2)
  String content;

  Note({
    String? id,
    required this.title,
    required this.content,
  }) : id = id ?? _uuid.v4();
}

import 'package:sqflite/sqflite.dart';
import 'package:uuid/uuid.dart';

const _uuid = Uuid();

Future<void> createTable(Database db) async {
  await db.execute('''
    CREATE TABLE IF NOT EXISTS tasks (
      id TEXT PRIMARY KEY,
      title TEXT NOT NULL,
      completed INTEGER NOT NULL DEFAULT 0
    )
  ''');
}

Future<String> insertTask(Database db, String title) async {
  final id = _uuid.v4();
  await db.insert('tasks', {'id': id, 'title': title, 'completed': 0});
  return id;
}

import 'package:flutter/material.dart';
import 'package:uuid/uuid.dart';

const _uuid = Uuid();

class TodoItem {
  final String id;
  final String text;
  bool done;

  TodoItem(this.text) : id = _uuid.v4(), done = false;
}

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

  @override
  State<TodoList> createState() => _TodoListState();
}

class _TodoListState extends State<TodoList> {
  final List<TodoItem> _items = [];

  void _addItem(String text) {
    setState(() => _items.add(TodoItem(text)));
  }

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: _items.length,
      itemBuilder: (context, index) {
        final item = _items[index];
        return ListTile(
          key: ValueKey(item.id), // UUID as stable widget key
          title: Text(item.text),
        );
      },
    );
  }
}

import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:uuid/uuid.dart';

const _uuid = Uuid();

class Note {
  final String id;
  final String content;
  const Note({required this.id, required this.content});
}

class NotesNotifier extends StateNotifier<List<Note>> {
  NotesNotifier() : super([]);

  void add(String content) {
    state = [...state, Note(id: _uuid.v4(), content: content)];
  }

  void remove(String id) {
    state = state.where((n) => n.id != id).toList();
  }
}

final notesProvider = StateNotifierProvider<NotesNotifier, List<Note>>(
  (ref) => NotesNotifier(),
);

import 'package:uuid/uuid.dart';

const _uuid = Uuid();

class SyncService {
  // Generate UUID locally - works offline
  // When connectivity returns, sync to server using the same UUID
  Future<String> createRecord(Map<String, dynamic> data) async {
    final id = _uuid.v4();
    data['id'] = id;

    // Save locally first
    await localDb.insert(data);

    // Queue for sync when online
    await syncQueue.add({'id': id, 'data': data, 'action': 'create'});

    return id; // Return immediately - no server round-trip needed
  }
}