Running on isolate instance has not been initialized on windows

[alexaccaci]

Using version 0.4.0 quick_usb init doen't work on isolate.
I'haven't this problem using the prevoius version 0.3.1.
I've attached an example.
Best Regards
Alex

import 'dart:async';
import 'dart:isolate';

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

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

runApp(MyHome());
}

class MyHome extends StatelessWidget {
@OverRide
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('Plugin example app'),
),
body: MyApp(),
),
);
}
}

class MyApp extends StatefulWidget {
@OverRide
_MyAppState createState() => _MyAppState();
}

class _MyAppState extends State {
@OverRide
void initState() {
super.initState();
init();
}

Future init() async {
UsbService.usbRecvPort = ReceivePort();
await Isolate.spawn(UsbService.loopUsb, UsbService.usbRecvPort!.sendPort);
}

@OverRide
Widget build(BuildContext context) {
return _buildColumn();
}

void log(String info) {
ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(info)));
}

Widget _buildColumn() {
return Column(
children: [
_init_exit(),
_getDeviceList(),
],
);
}

Widget _init_exit() {
return Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
ElevatedButton(
child: Text('init'),
onPressed: () async {
var init = await QuickUsb.init();
log('init $init');
},
),
ElevatedButton(
child: Text('exit'),
onPressed: () async {
await QuickUsb.exit();
log('exit');
},
),
],
);
}

List? _deviceList;

Widget _getDeviceList() {
return ElevatedButton(
child: Text('getDeviceList'),
onPressed: () async {
_deviceList = await QuickUsb.getDeviceList();
log('deviceList $_deviceList');
},
);
}
}

class UsbService {
static SendPort? usbSendPort;
static ReceivePort? usbRecvPort;

static void loopUsb(SendPort sendPort) async {
ReceivePort p = ReceivePort();
sendPort.send(p.sendPort);

while (true) {
  await Future.delayed(const Duration(seconds: 1));
  try {
    var init = await QuickUsb.init();
    print('init $init');

    var list = await QuickUsb.getDeviceList();
    print(list);

    await QuickUsb.exit();
  } catch (e) {
    print(e);
  }
}

}
}

[alexaccaci]

I have resolved the problem using the following article:
https://medium.com/flutter/introducing-background-isolate-channels-7a299609cad8

But there is another small error in your code that needs to correct:

class QuickUsbWindows extends _QuickUsbDesktop {
// For example/.dart_tool/flutter_build/generated_main.dart
static registerWith() {
QuickUsbPlatform.instance = QuickUsbMacos();
_libusb = Libusb(DynamicLibrary.open('libusb-1.0.23.dll'));
}
}

has to be changed with:

class QuickUsbWindows extends _QuickUsbDesktop {
// For example/.dart_tool/flutter_build/generated_main.dart
static registerWith() {
QuickUsbPlatform.instance = QuickUsbWindows();//not QuickUsbMacos!!!
_libusb = Libusb(DynamicLibrary.open('libusb-1.0.23.dll'));
}
}

Best regards
Alex