Flutter Web平台相关导入未按预期工作问题排查

我需要实现同时支持桌面（Windows、Mac）和Web平台的串口通信方案，由于没有开箱即用的跨平台库，因此分别使用flutter_libserialport（桌面）和serial（Web）库。

为实现平台针对性导入，我参考相关方案进行了实现，但Windows编译正常，Web编译时却报错。我不确定问题出在哪里，怀疑平台选择性导入未生效，想确认dart.library.html是否已被废弃？

相关代码文件 #

抽象类（Iserial.dart） #

import 'package:dev_tools/adapters/serial_stub.dart'
    if (dart.library.io) 'package:dev_tools/adapters/desktop_serial.dart'
    if (dart.library.html) 'package:dev_tools/adapters/web_serial.dart';

abstract class SerialInterface {
  factory SerialInterface() => getSerialInterface();
  dynamic getPort(String portName);
  dynamic getSelectedPort();
  List<String> getAvailablePorts();
  bool close();
  String get name;
  bool get isOpen;
}

Stub文件（serial_stub.dart） #

import 'package:dev_tools/interfaces/Iserial.dart';

SerialInterface getSerialInterface() => throw UnsupportedError(
    'Cannot create a keyfinder without the packages dart:html or package:shared_preferences');

桌面端实现（desktop_serial.dart） #

import 'package:dev_tools/interfaces/Iserial.dart';

SerialInterface getSerialInterface() => DesktopSerialInterface();

class DesktopSerialInterface implements SerialInterface {
  // Map<String, SerialPort?> portList = {};
  // SerialPort? _selectedPort;
  // SerialPortReader? _serialPortReader;
  // Stream? _incomingDataStream;
  // String serialData = "";

  DesktopSerialInterface() {
    print("DesktopSerial Initialized");
  }

  @override
  List<String> getAvailablePorts() {
    List<String> serialNameList = [];
    return serialNameList;
  }

  @override
  dynamic getPort(String portName) {
    return null;
  }

  @override
  dynamic getSelectedPort() {
    return null;
  }

  @override
  bool close() {
    return false;
  }

  String get name => throw UnimplementedError("name getter not implemented");

  bool get isOpen => throw UnimplementedError("isOpen getter not implemented");
}

Web端实现（web_serial.dart） #

import 'package:dev_tools/interfaces/Iserial.dart';

SerialInterface getSerialAdapter() => WebSerialInterface();

class WebSerialInterface implements SerialInterface {
  // Map<String, SerialPort?> portList = {};
  // SerialPort? _selectedPort;
  WebSerialInterface() {
    print("WebSerial Initialized");
    // window.navigator.serial.requestPort().then((port) => _selectedPort = port);
    // _selectedPort!.readable.reader.read().asStream()
  }

  @override
  List<String> getAvailablePorts() {
    List<String> serialNameList = [];
    return serialNameList;
  }

  @override
  dynamic getPort(String portName) {
    // window.navigator.serial.requestPort().then((port) => _selectedPort = port);
    return null;
  }

  @override
  dynamic getSelectedPort() {
    return null;
  }

  @override
  bool close() {
    return false;
  }

  String get name => throw UnimplementedError("name getter not implemented");

  bool get isOpen => throw UnimplementedError("isOpen getter not implemented");
}

内容的提问来源于stack exchange，提问作者Chameera Subasinghe