Snippet for initializing OneSignal User Model SDK in Flutter

main.dart

import 'package:flutter/material.dart';
import 'package:onesignal_flutter/onesignal_flutter.dart';
import 'package:flutter_application_la/live_actiivties_manager.dart';

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

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

  @override
  Widget build(BuildContext context) {
    LiveActivitiesManager.register();
    OneSignal.initialize("<<YOUR_APP_ID>>");
    OneSignal.Notifications.requestPermission(true);

    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final TextEditingController _activityIdController = TextEditingController(text: '');
  final TextEditingController _nameController = TextEditingController(text: 'Test LA Name');
  final TextEditingController _emojiController = TextEditingController(text: '😀');

  void _startLiveActivity() {
    LiveActivitiesManager.startLiveActivity(_activityIdController.text, _nameController.text, _emojiController.text);
  }

  @override
  Widget build(BuildContext context) {  
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              TextFormField(
                controller: _activityIdController,
                decoration: const InputDecoration(
                  border: UnderlineInputBorder(),
                  labelText: 'Activity ID:',
                ),
              ),
              TextFormField(
                controller: _nameController,
                decoration: const InputDecoration(
                  border: UnderlineInputBorder(),
                  labelText: 'Name:',
                ),
              ),
              TextFormField(
                controller: _emojiController,
                decoration: const InputDecoration(
                  border: UnderlineInputBorder(),
                  labelText: 'Emoji:',
                ),
              ),
            ],
          )
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _startLiveActivity,
        tooltip: 'Start Live Activity',
        child: const Icon(Icons.add),
      ),
    );
  }
}