Flutter后台服务插件flutter_background_service_android的使用

简介

flutter_background_service_android 是 flutter_background_service 插件的 Android 实现。通过使用 flutter_background_service，你可以在 Flutter 应用中轻松地创建和管理后台服务。

使用方法

添加依赖

首先，在你的 pubspec.yaml 文件中添加 flutter_background_service 依赖：

dependencies:
  flutter:
    sdk: flutter
  flutter_background_service: ^0.2.0

然后运行 flutter pub get 来安装依赖。

初始化后台服务

在你的主入口文件（通常是 main.dart）中初始化后台服务：

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';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  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: onIosForeground,

      // you have to enable background fetch capability on xcode project
      onBackground: onIosBackground,
    ),
  );

  runApp(MyApp());
}

// to ensure this executed
// run isolate in background
@pragma('vm:entry-point')
void onStart(ServiceInstance service) async {
  // Only available for flutter 3.0.0 and later
  DartPluginRegistrant.ensureInitialized();

  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 {
    if (service is AndroidServiceInstance) {
      service.setForegroundNotificationInfo(
        title: "My Background Service",
        content: "Running in background",
      );
    }
  });
}

@pragma('vm:entry-point')
void onIosForeground(ServiceInstance service) {
  // you can handle iOS foreground event here
}

@pragma('vm:entry-point')
void onIosBackground(ServiceInstance service) {
  // you can handle iOS background event here
}

创建UI

在你的 Flutter 应用中创建一个简单的 UI 来控制后台服务：

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter Background Service'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              ElevatedButton(
                onPressed: () {
                  FlutterBackgroundService().invoke('setAsForeground');
                },
                child: Text('Start Foreground Service'),
              ),
              ElevatedButton(
                onPressed: () {
                  FlutterBackgroundService().invoke('setAsBackground');
                },
                child: Text('Start Background Service'),
              ),
              ElevatedButton(
                onPressed: () {
                  FlutterBackgroundService().invoke('stopService');
                },
                child: Text('Stop Service'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

配置AndroidManifest.xml

确保在你的 AndroidManifest.xml 文件中添加必要的权限和配置：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.yourapp">

    <application
        android:label="yourapp"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|presentation"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">
            <!-- Specifies an Android theme to apply to this Activity as soon as
                 the Android process has started. This theme is visible to the user
                 while the Flutter UI initializes. After that, this theme continues
                 to determine the Window background behind the Flutter UI. -->
            <meta-data
              android:name="io.flutter.embedding.android.NormalTheme"
              android:resource="@style/NormalTheme"
              />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <!-- Don't delete the meta-data below.
             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
        <service
            android:name="dev.flutter.plugins.backgroundservice.BackgroundService"
            android:exported="false"
            android:enabled="true">
            <intent-filter>
                <action android:name="dev.flutter.plugins.backgroundservice.BackgroundService" />
            </intent-filter>
        </service>
    </application>

    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
</manifest>

运行应用

现在你可以运行你的 Flutter 应用，点击按钮来启动和停止后台服务。

总结

通过 flutter_background_service 和 flutter_background_service_android，你可以在 Flutter 应用中轻松实现后台服务功能。希望这个示例能帮助你快速上手并实现你的需求。如果有任何问题或需要进一步的帮助，请随时提问。