Flutter & Background fetch - How to handle a simple example? - flutter

Question

I am really wondering how to use the package https://pub.dev/packages/background_fetch.
I want to run a simple task to grab entries from my sqllite DB to change status.
On the main.dart file, I have :
Future main() async {
WidgetsFlutterBinding.ensureInitialized();
initPlatformState();
await DotEnv().load('.env');
runApp(MyApp());
// Register to receive BackgroundFetch events after app is terminated.
// Requires {stopOnTerminate: false, enableHeadless: true}
BackgroundFetch.registerHeadlessTask(backgroundFetchHeadlessTask);
BackgroundFetch.start();
}
First, I am really not if I have to put : BackgroundFetch.start(); ?
Then, here is my function called :
// Platform messages are asynchronous, so we initialize in an async method.
Future<void> initPlatformState() async {
// Configure BackgroundFetch.
BackgroundFetch.configure(BackgroundFetchConfig(
minimumFetchInterval: 15,
stopOnTerminate: false,
enableHeadless: false,
requiresBatteryNotLow: false,
requiresCharging: false,
requiresStorageNotLow: false,
requiresDeviceIdle: false,
requiredNetworkType: NetworkType.ANY
), (String taskId) async {
// This is the fetch-event callback.
print("[BackgroundFetch] Event received $taskId");
// take all photos not uploaded
final repo = di.get<DossierRepository>();
final photosNotUploaded = await repo.getPhotosNotUploaded();
await for (final photo in Stream.fromIterable(photosNotUploaded)) {
// resend them simply
repo.resendPhoto(photo.dossierId, photo.photoId);
}
// IMPORTANT: You must signal completion of your task or the OS can punish your app
// for taking too long in the background.
BackgroundFetch.finish(taskId);
}).then((int status) {
print('[BackgroundFetch] configure success: $status');
}).catchError((e) {
print('[BackgroundFetch] configure ERROR: $e');
});
}
I have this warning :
[TSBackgroundFetch start] Task flutter_background_fetch already registered
I understand I have to check if the task is not registered, but how ? And if I make changes to my code, I need to "destroy" the old task and register the new one ?
And is it the good way of using this plugin ? I have only 1 Task for my app, I want it to run all the time. Do I have to register Tasks ? Or this is enough ?

Answer 1

flutter_background_fetch is the default taskid of BackgroundFetch, which will be auto-registered by BackgroundFetch when initPlatformState. It means that you should not use flutter_background_fetch as a taskid.