flutter_foreground_task 3.7.3

This plugin is used to implement a foreground service on the Android platform.

example/lib/main.dart

import 'dart:isolate';

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

void main() => runApp(const ExampleApp());

// The callback function should always be a top-level function.
void startCallback() {
  // The setTaskHandler function must be called to handle the task in the background.
  FlutterForegroundTask.setTaskHandler(MyTaskHandler());
}

class MyTaskHandler extends TaskHandler {
  SendPort? _sendPort;
  int _eventCount = 0;

  @override
  Future<void> onStart(DateTime timestamp, SendPort? sendPort) async {
    _sendPort = sendPort;

    // You can use the getData function to get the stored data.
    final customData =
        await FlutterForegroundTask.getData<String>(key: 'customData');
    print('customData: $customData');
  }

  @override
  Future<void> onEvent(DateTime timestamp, SendPort? sendPort) async {
    FlutterForegroundTask.updateService(
      notificationTitle: 'MyTaskHandler',
      notificationText: 'eventCount: $_eventCount'
    );

    // Send data to the main isolate.
    sendPort?.send(_eventCount);

    _eventCount++;
  }

  @override
  Future<void> onDestroy(DateTime timestamp, SendPort? sendPort) async {
    // You can use the clearAllData function to clear all the stored data.
    await FlutterForegroundTask.clearAllData();
  }

  @override
  void onButtonPressed(String id) {
    // Called when the notification button on the Android platform is pressed.
    print('onButtonPressed >> $id');
  }

  @override
  void onNotificationPressed() {
    // Called when the notification itself on the Android platform is pressed.
    //
    // "android.permission.SYSTEM_ALERT_WINDOW" permission must be granted for
    // this function to be called.

    // Note that the app will only route to "/resume-route" when it is exited so
    // it will usually be necessary to send a message through the send port to
    // signal it to restore state when the app is already started.
    FlutterForegroundTask.launchApp("/resume-route");
    _sendPort?.send('onNotificationPressed');
  }
}

class ExampleApp extends StatelessWidget {
  const ExampleApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      initialRoute: '/',
      routes: {
        '/': (context) => const ExamplePage(),
        '/resume-route': (context) => const ResumeRoutePage(),
      },
    );
  }
}

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

  @override
  State<StatefulWidget> createState() => _ExamplePageState();
}

class _ExamplePageState extends State<ExamplePage> {
  ReceivePort? _receivePort;

  Future<void> _initForegroundTask() async {
    await FlutterForegroundTask.init(
      androidNotificationOptions: AndroidNotificationOptions(
        channelId: 'notification_channel_id',
        channelName: 'Foreground Notification',
        channelDescription:
            'This notification appears when the foreground service is running.',
        channelImportance: NotificationChannelImportance.LOW,
        priority: NotificationPriority.LOW,
        iconData: const NotificationIconData(
          resType: ResourceType.mipmap,
          resPrefix: ResourcePrefix.ic,
          name: 'launcher',
          backgroundColor: Colors.orange,
        ),
        buttons: [
          const NotificationButton(id: 'sendButton', text: 'Send'),
          const NotificationButton(id: 'testButton', text: 'Test'),
        ],
      ),
      iosNotificationOptions: const IOSNotificationOptions(
        showNotification: true,
        playSound: false,
      ),
      foregroundTaskOptions: const ForegroundTaskOptions(
        interval: 5000,
        autoRunOnBoot: true,
        allowWifiLock: true,
      ),
      printDevLog: true,
    );
  }

  Future<bool> _startForegroundTask() async {
    // "android.permission.SYSTEM_ALERT_WINDOW" permission must be granted for
    // onNotificationPressed function to be called.
    //
    // When the notification is pressed while permission is denied,
    // the onNotificationPressed function is not called and the app opens.
    //
    // If you do not use the onNotificationPressed or launchApp function,
    // you do not need to write this code.
    if (!await FlutterForegroundTask.canDrawOverlays) {
      final isGranted =
          await FlutterForegroundTask.openSystemAlertWindowSettings();
      if (!isGranted) {
        print('SYSTEM_ALERT_WINDOW permission denied!');
        return false;
      }
    }

    // You can save data using the saveData function.
    await FlutterForegroundTask.saveData(key: 'customData', value: 'hello');

    ReceivePort? receivePort;
    if (await FlutterForegroundTask.isRunningService) {
      receivePort = await FlutterForegroundTask.restartService();
    } else {
      receivePort = await FlutterForegroundTask.startService(
        notificationTitle: 'Foreground Service is running',
        notificationText: 'Tap to return to the app',
        callback: startCallback,
      );
    }

    return _registerReceivePort(receivePort);
  }

  Future<bool> _stopForegroundTask() async {
    return await FlutterForegroundTask.stopService();
  }

  bool _registerReceivePort(ReceivePort? receivePort) {
    _closeReceivePort();

    if (receivePort != null) {
      _receivePort = receivePort;
      _receivePort?.listen((message) {
        if (message is int) {
          print('eventCount: $message');
        } else if (message is String) {
          if (message == 'onNotificationPressed') {
            Navigator.of(context).pushNamed('/resume-route');
          }
        } else if (message is DateTime) {
          print('timestamp: ${message.toString()}');
        }
      });

      return true;
    }

    return false;
  }

  void _closeReceivePort() {
    _receivePort?.close();
    _receivePort = null;
  }

  T? _ambiguate<T>(T? value) => value;

  @override
  void initState() {
    super.initState();
    _initForegroundTask();
    _ambiguate(WidgetsBinding.instance)?.addPostFrameCallback((_) async {
      // You can get the previous ReceivePort without restarting the service.
      if (await FlutterForegroundTask.isRunningService) {
        final newReceivePort = await FlutterForegroundTask.receivePort;
        _registerReceivePort(newReceivePort);
      }
    });
  }

  @override
  void dispose() {
    _closeReceivePort();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    // A widget that prevents the app from closing when the foreground service is running.
    // This widget must be declared above the [Scaffold] widget.
    return WithForegroundTask(
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Flutter Foreground Task'),
          centerTitle: true,
        ),
        body: _buildContentView(),
      ),
    );
  }

  Widget _buildContentView() {
    buttonBuilder(String text, {VoidCallback? onPressed}) {
      return ElevatedButton(
        child: Text(text),
        onPressed: onPressed,
      );
    }

    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          buttonBuilder('start', onPressed: _startForegroundTask),
          buttonBuilder('stop', onPressed: _stopForegroundTask),
        ],
      ),
    );
  }
}

class ResumeRoutePage extends StatelessWidget {
  const ResumeRoutePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Resume Route'),
        centerTitle: true,
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: () {
            // Navigate back to first route when tapped.
            Navigator.of(context).pop();
          },
          child: const Text('Go back!'),
        ),
      ),
    );
  }
}