A flutter plugin for execute dart code in background.

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Android

  • To change notification icon, just add drawable icon with name ic_bg_service_small.

WARNING:

Please make sure your project already use the version of gradle tools below:

  • in android/build.gradle classpath 'com.android.tools.build:gradle:7.4.2'
  • in android/build.gradle ext.kotlin_version = '1.8.10'
  • in android/gradle/wrapper/gradle-wrapper.properties distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-all.zip

Configuration required for Foreground Services on Android 14 (SDK 34)

Applications that target SDK 34 and use foreground services need to include some additional configuration to declare the type of foreground service they use:

  • Determine the type of foreground service your app requires by consulting the documentation

  • Add the corresponding permission to your android/app/src/main/AndroidManifest.xml file:

<manifest xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" package="com.example">
  ...
  <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
  <!--
    Permission to use here depends on the value you picked for foregroundServiceType - see the Android documentation.
    Eg, if you picked 'location', use 'android.permission.FOREGROUND_SERVICE_LOCATION'
  -->
  <uses-permission android:name="android.permission.FOREGROUND_SERVICE_..." />
  <application
        android:label="example"
        android:name="${applicationName}"
        android:icon="@mipmap/ic_launcher"
        ...>

        <activity
            android:name=".MainActivity"
            android:exported="true"
            ...>

        <!--Add this-->
        <service
            android:name="id.flutter.flutter_background_service.BackgroundService"
            android:foregroundServiceType="WhatForegroundServiceTypeDoYouWant"
        />
        <!--end-->

        ...
  ...
  </application>
</manifest>

WARNING:

  • YOU MUST MAKE SURE ANY REQUIRED PERMISSIONS TO BE GRANTED BEFORE YOU START THE SERVICE

Using custom notification for Foreground Service

You can make your own custom notification for foreground service. It can give you more power to make notifications more attractive to users, for example adding progressbars, buttons, actions, etc. The example below is using flutter_local_notifications plugin, but you can use any other notification plugin. You can follow how to make it below:

  • Notification Channel

Future<void> main() async {
    WidgetsFlutterBinding.ensureInitialized();
    await initializeService();

    runApp(MyApp());
}

// this will be used as notification channel id
const notificationChannelId = 'my_foreground';

// this will be used for notification id, So you can update your custom notification with this id.
const notificationId = 888;

Future<void> initializeService() async {
  final service = FlutterBackgroundService();

  const AndroidNotificationChannel channel = AndroidNotificationChannel(
    notificationChannelId, // id
    'MY FOREGROUND SERVICE', // title
    description:
        'This channel is used for important notifications.', // description
    importance: Importance.low, // importance must be at low or higher level
  );

  final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();

  await flutterLocalNotificationsPlugin
      .resolvePlatformSpecificImplementation<
          AndroidFlutterLocalNotificationsPlugin>()
      ?.createNotificationChannel(channel);

  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,

      notificationChannelId: notificationChannelId, // this must match with notification channel you created above.
      initialNotificationTitle: 'AWESOME SERVICE',
      initialNotificationContent: 'Initializing',
      foregroundServiceNotificationId: notificationId,
    ),
    ...
  • Update notification info

Future<void> onStart(ServiceInstance service) async {
  // Only available for flutter 3.0.0 and later
  DartPluginRegistrant.ensureInitialized();

  final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
      FlutterLocalNotificationsPlugin();

  // bring to foreground
  Timer.periodic(const Duration(seconds: 1), (timer) async {
    if (service is AndroidServiceInstance) {
      if (await service.isForegroundService()) {
        flutterLocalNotificationsPlugin.show(
          notificationId,
          'COOL SERVICE',
          'Awesome ${DateTime.now()}',
          const NotificationDetails(
            android: AndroidNotificationDetails(
              notificationChannelId,
              'MY FOREGROUND SERVICE',
              icon: 'ic_bg_service_small',
              ongoing: true,
            ),
          ),
        );
      }
    }
  });
}

Using Background Service Even when The Application Is Closed

You can use this feature in order to execute code in background. Very useful to fetch realtime data from a server and push notifications.

Must Know:

  • isForegroundMode: false : The background mode requires running in release mode and requires disabling battery optimization so that the service stays up when the user closes the application.
  • isForegroundMode: true : Displays a silent notification when used according to Android's Policy
  • Simple implementation using Socket.io
import 'dart:async';
import 'dart:ui';
import 'package:socket_io_client/socket_io_client.dart' as io;
import 'package:flutter/material.dart';
import 'package:flutter_background_service/flutter_background_service.dart';

Future<void> main() async {
    WidgetsFlutterBinding.ensureInitialized();
    await initializeService();

    runApp(MyApp());
}

void startBackgroundService() {
  final service = FlutterBackgroundService();
  service.startService();
}

void stopBackgroundService() {
  final service = FlutterBackgroundService();
  service.invoke("stop");
}

Future<void> initializeService() async {
  final service = FlutterBackgroundService();

  await service.configure(
    iosConfiguration: IosConfiguration(
      autoStart: true,
      onForeground: onStart,
      onBackground: onIosBackground,
    ),
    androidConfiguration: AndroidConfiguration(
      autoStart: true,
      onStart: onStart,
      isForegroundMode: false,
      autoStartOnBoot: true,
    ),
  );
}

@pragma('vm:entry-point')
Future<bool> onIosBackground(ServiceInstance service) async {
  WidgetsFlutterBinding.ensureInitialized();
  DartPluginRegistrant.ensureInitialized();

  return true;
}

@pragma('vm:entry-point')
void onStart(ServiceInstance service) async {
  final socket = io.io("your-server-url", <String, dynamic>{
    'transports': ['websocket'],
    'autoConnect': true,
  });
  socket.onConnect((_) {
    print('Connected. Socket ID: ${socket.id}');
    // Implement your socket logic here
    // For example, you can listen for events or send data
  });

  socket.onDisconnect((_) {
    print('Disconnected');
  });
   socket.on("event-name", (data) {
    //do something here like pushing a notification
  });
  service.on("stop").listen((event) {
    service.stopSelf();
    print("background process is now stopped");
  });

  service.on("start").listen((event) {});

  Timer.periodic(const Duration(seconds: 1), (timer) {
    socket.emit("event-name", "your-message");
    print("service is successfully running ${DateTime.now().second}");
  });
}

iOS

  • Enable background_fetch capability in xcode (optional), if you wish ios to execute IosConfiguration.onBackground callback.

  • For iOS 13 and Later (using BGTaskScheduler), insert lines below into your ios/Runner/Info.plist

<key>BGTaskSchedulerPermittedIdentifiers</key>
<array>
    <string>dev.flutter.background.refresh</string>
</array>
  • You can also using your own custom identifier In ios/Runner/AppDelegate.swift add line below
import UIKit
import Flutter
import flutter_background_service_ios // add this

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    /// Add this line
    SwiftFlutterBackgroundServicePlugin.taskIdentifier = "your.custom.task.identifier"

    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

Usage

  • Call FlutterBackgroundService.configure() to configure handler that will be executed by the Service.

It's highly recommended to call this method in main() method to ensure the callback handler updated.

  • Call FlutterBackgroundService.start to start the Service if autoStart is not enabled.

  • Since the Service using Isolates, You won't be able to share reference between UI and Service. You can communicate between UI and Service using invoke() and on(String method).

Migration

  • sendData() renamed to invoke(String method)
  • onDataReceived() renamed to on(String method)
  • Now you have to use ServiceInstance object inside onStart method instead of creating a new FlutterBackgroundService object. See the example project.
  • Only use FlutterBackgroundService class in UI Isolate and ServiceInstance in background isolate.

FAQ

Why the service not started automatically?

Some android device manufacturers have a custom android os for example MIUI from Xiaomi. You have to deal with that policy.

Service killed by system and not respawn?

Try to disable battery optimization for your app.

My notification icon not changed, how to solve it?

Make sure you had created notification icons named ic_bg_service_small and placed in res/drawable-mdpi, res/drawable-hdpi, res/drawable-xhdpi, res/drawable-xxhdpi for PNGs file, and res/drawable-anydpi-v24 for XML (Vector) file.

Service not running in Release Mode

Add @pragma('vm:entry-point') to the onStart() method. Example:


@pragma('vm:entry-point')
void onStart(ServiceInstance service){
  ...
}

Service terminated when app is in background (minimized) on iOS

Keep in your mind, iOS doesn't have a long running service feature like Android. So, it's not possible to keep your application running when it's in background because the OS will suspend your application soon. Currently, this plugin provide onBackground method, that will be executed periodically by Background Fetch capability provided by iOS. It cannot be faster than 15 minutes and only alive about 15-30 seconds.

Discord

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Libraries

flutter_background_service