flutter_background_service/example/lib/main.dart

import 'dart:async';
import 'dart:io';
import 'dart:ui';

import 'package:device_info_plus/device_info_plus.dart';
import 'package:flutter/material.dart';
import 'package:flutter_background_service/flutter_background_service.dart';
import 'package:flutter_background_service_android/flutter_background_service_android.dart';
import 'package:shared_preferences/shared_preferences.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await initializeService();
  runApp(const MyApp());
}

Future<void> initializeService() async {
  final service = FlutterBackgroundService();
  await service.configure(
    androidConfiguration: AndroidConfiguration(
      // this will be executed when app is in foreground or background in separated isolate
      onStart: onStart,

      // auto start service
      autoStart: true,
      isForegroundMode: true,
    ),
    iosConfiguration: IosConfiguration(
      // auto start service
      autoStart: true,

      // this will be executed when app is in foreground in separated isolate
      onForeground: onStart,

      // you have to enable background fetch capability on xcode project
      onBackground: onIosBackground,
    ),
  );
  service.startService();
}

// to ensure this is executed
// run app from xcode, then from xcode menu, select Simulate Background Fetch
bool onIosBackground(ServiceInstance service) {
  WidgetsFlutterBinding.ensureInitialized();
  print('FLUTTER BACKGROUND FETCH');

  return true;
}

void onStart(ServiceInstance service) async {

  // Only available for flutter 3.0.0 and later
  DartPluginRegistrant.ensureInitialized();

  // For flutter prior to version 3.0.0
  // We have to register the plugin manually
  

  SharedPreferences preferences = await SharedPreferences.getInstance();
  await preferences.setString("hello", "world");

  if (service is AndroidServiceInstance) {
    service.on('setAsForeground').listen((event) {
      service.setAsForegroundService();
    });

    service.on('setAsBackground').listen((event) {
      service.setAsBackgroundService();
    });
  }

  service.on('stopService').listen((event) {
    service.stopSelf();
  });

  // bring to foreground
  Timer.periodic(const Duration(seconds: 1), (timer) async {
    final hello = preferences.getString("hello");
    print(hello);

    if (service is AndroidServiceInstance) {
      service.setForegroundNotificationInfo(
        title: "My App Service",
        content: "Updated at ${DateTime.now()}",
      );
    }

    /// you can see this log in logcat
    print('FLUTTER BACKGROUND SERVICE: ${DateTime.now()}');

    // test using external plugin
    final deviceInfo = DeviceInfoPlugin();
    String? device;
    if (Platform.isAndroid) {
      final androidInfo = await deviceInfo.androidInfo;
      device = androidInfo.model;
    }

    if (Platform.isIOS) {
      final iosInfo = await deviceInfo.iosInfo;
      device = iosInfo.model;
    }

    service.invoke(
      'update',
      {
        "current_date": DateTime.now().toIso8601String(),
        "device": device,
      },
    );
  });
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String text = "Stop Service";
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Service App'),
        ),
        body: Column(
          children: [
            StreamBuilder<Map<String, dynamic>?>(
              stream: FlutterBackgroundService().on('update'),
              builder: (context, snapshot) {
                if (!snapshot.hasData) {
                  return const Center(
                    child: CircularProgressIndicator(),
                  );
                }

                final data = snapshot.data!;
                String? device = data["device"];
                DateTime? date = DateTime.tryParse(data["current_date"]);
                return Column(
                  children: [
                    Text(device ?? 'Unknown'),
                    Text(date.toString()),
                  ],
                );
              },
            ),
            ElevatedButton(
              child: const Text("Foreground Mode"),
              onPressed: () {
                FlutterBackgroundService().invoke("setAsForeground");
              },
            ),
            ElevatedButton(
              child: const Text("Background Mode"),
              onPressed: () {
                FlutterBackgroundService().invoke("setAsBackground");
              },
            ),
            ElevatedButton(
              child: Text(text),
              onPressed: () async {
                final service = FlutterBackgroundService();
                var isRunning = await service.isRunning();
                if (isRunning) {
                  service.invoke("stopService");
                } else {
                  service.startService();
                }

                if (!isRunning) {
                  text = 'Stop Service';
                } else {
                  text = 'Start Service';
                }
                setState(() {});
              },
            ),
          ],
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () {},
          child: const Icon(Icons.play_arrow),
        ),
      ),
    );
  }
}