Unable to start foreground service using flutter_foreground_task package when called from callbackDispatcher.

[BigYajuu]

Technology	Version
Android SDK version	29
Workmanager version	0.5.2

Synopsis

I wanted to register a periodic task that could start foreground service (FGS) after a set delay, but it failed to run. The execution of the foreground service is done by yet another flutter package called flutter_foreground_task https://pub.dev/packages/flutter_foreground_task.

Details

The start of the FGS is triggered using FlutterForegroundTask.startService from the flutter_foreground_task package, and it is called from inside of the callback body of Workmanager().executeTask((task, inputData) async { ... }), which is called from the top-level callbackDispatcher() entry point. Therefore by design, when Workmanager().registerPeriodicTask( ... ); is called the FGS should begin autonomously, but it did not. My guess is that Android disallows FGS to launch from another isolate without proper passing of Android context. But since I am using a third-party FGS package there's really no wiggle room here.

I am beginning to lean towards to the concept of Android's ForegroundInfo though. And someone #573 has already raised a merge request regarding this feature, ready to be released. I am paying close attention to the progress of this.

Output of flutter doctor -v (partial)

[√] Flutter (Channel stable, 3.22.1, on Microsoft Windows [Version 10.0.22631.4602], locale en-US)
• Flutter version 3.22.1 on channel stable at C:\dev\flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision a14f74ff3a (7 months ago), 2024-05-22 11:08:21 -0500
• Engine revision 55eae6864b
• Dart version 3.4.1
• DevTools version 2.34.3

[√] Windows Version (Installed version of Windows is version 10 or higher)

[√] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
• Android SDK at C:\Users\Chuyue Wu\AppData\Local\Android\sdk
• Platform android-34, build-tools 34.0.0
• Java binary at: C:\Program Files\Android\Android Studio1\jbr\bin\java
• Java version OpenJDK Runtime Environment (build 17.0.9+0--11185874)
• All Android licenses accepted.

[√] Android Studio (version 2023.2)
• Android Studio at C:\Program Files\Android\Android Studio1
• Flutter plugin can be installed from:
https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 17.0.9+0--11185874)

[√] VS Code (version 1.94.2)
• VS Code at C:\Users\Chuyue Wu\AppData\Local\Programs\Microsoft VS Code
• Flutter extension version 3.102.0