can you change the dropdown box in the flutter code below to a windows type
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:file_picker/file_picker.dart';
import 'package:window_manager/window_manager.dart';

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

  if (Platform.isWindows || Platform.isLinux || Platform.isMacOS) {
    await windowManager.ensureInitialized();

    windowManager.waitUntilReadyToShow().then((_) async {
      await windowManager.setTitle('JMS AG J-TF ini File Utility');
      const size = Size(846, 530);
      await windowManager.setSize(size, animate: false);
      await windowManager.setMinimumSize(size);
      await windowManager.setMaximumSize(size);
      await windowManager.setResizable(false);
      await windowManager.setMaximizable(false);
      await windowManager.show();
      await windowManager.focus();
    });
  }

  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: HomeScreen(),
    );
  }
}

class HomeScreen extends StatefulWidget {
  @override
  _HomeScreenState createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  String upperTextBoxContent = '';
  String lowerTextBoxContent = '';
  String dropdownValue = 'kN';

  bool isFilePickerOpen = false;

  void _loadIniFile() async {
    if (isFilePickerOpen) return;

    setState(() {
      isFilePickerOpen = true;
    });

    FilePickerResult? result = await FilePicker.platform.pickFiles(
      type: FileType.custom,
      allowedExtensions: ['ini'],
    );

    if (result != null) {
      PlatformFile file = result.files.first;
      String? filePath = file.path;

      if (filePath != null) {
        final fileContent = await File(filePath).readAsString();
        setState(() {
          lowerTextBoxContent = fileContent;
        });
      }
    } else {
      print('User canceled file picker');
    }

    setState(() {
      isFilePickerOpen = false;
    });
  }

  @override
  Widget build(BuildContext context) {
    double labelWidth = 130.0;
    double dropdownWidth = 100.0;
    double inputFieldWidth = 80.0;
    double spacing = 10.0;

    return Scaffold(
      body: Column(
        children: <Widget>[
          SizedBox(
            height: 30,
            child: Container(
              width: double.infinity,
              color: Color.fromRGBO(0, 128, 192, 1.0),
              child: Center(
                child: Text(
                  'JMS AG J-TF ini File Utility',
                  style: TextStyle(
                    fontSize: 16,
                    color: Colors.white,
                    fontWeight: FontWeight.bold,
                  ),
                ),
              ),
            ),
          ),
          Expanded(
            child: Row(
              children: <Widget>[
                Expanded(
                  child: Container(
                    color: Colors.white,
                    padding: EdgeInsets.all(8.0),
                    child: Container(
                      height: 170.0,
                      decoration: BoxDecoration(
                        color: Color.fromRGBO(0, 128, 192, 1.0),
                        borderRadius: BorderRadius.circular(6.0),
                        border: Border.all(color: Colors.black),
                      ),
                      padding: EdgeInsets.all(16.0),
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                        children: [
                          Text(
                            'JT-F Device',
                            style: TextStyle(
                              color: Colors.white,
                              fontSize: 16,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                          Row(
                            crossAxisAlignment: CrossAxisAlignment.center,
                            children: [
                              Container(
                                width: labelWidth,
                                child: Text(
                                  'Model No:',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                              Expanded(
                                child: SizedBox(
                                  height: 20.0,
                                  child: TextField(
                                    decoration: InputDecoration(
                                      isDense: true,
                                      contentPadding: EdgeInsets.symmetric(
                                          vertical: 0, horizontal: 8),
                                      filled: true,
                                      fillColor: Colors.white,
                                      border: OutlineInputBorder(),
                                    ),
                                  ),
                                ),
                              ),
                            ],
                          ),
                          Row(
                            crossAxisAlignment: CrossAxisAlignment.center,
                            children: [
                              Container(
                                width: labelWidth,
                                child: Text(
                                  'Serial No:',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                              Expanded(
                                child: SizedBox(
                                  height: 20.0,
                                  child: TextField(
                                    decoration: InputDecoration(
                                      isDense: true,
                                      contentPadding: EdgeInsets.symmetric(
                                          vertical: 0, horizontal: 8),
                                      filled: true,
                                      fillColor: Colors.white,
                                      border: OutlineInputBorder(),
                                    ),
                                  ),
                                ),
                              ),
                            ],
                          ),
                          Row(
                            crossAxisAlignment: CrossAxisAlignment.center,
                            children: [
                              Container(
                                width: labelWidth,
                                child: Text(
                                  'Manufacturer:',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                              Expanded(
                                child: SizedBox(
                                  height: 20.0,
                                  child: TextField(
                                    decoration: InputDecoration(
                                      isDense: true,
                                      contentPadding: EdgeInsets.symmetric(
                                          vertical: 0, horizontal: 8),
                                      filled: true,
                                      fillColor: Colors.white,
                                      border: OutlineInputBorder(),
                                    ),
                                  ),
                                ),
                              ),
                            ],
                          ),
                          Row(
                            crossAxisAlignment: CrossAxisAlignment.center,
                            children: [
                              Container(
                                width: labelWidth,
                                child: Text(
                                  'Max. Capacity/SWL:',
                                  style: TextStyle(color: Colors.white),
                                ),
                              ),
                              SizedBox(width: spacing),
                              Container(
                                width: inputFieldWidth,
                                child: SizedBox(
                                  height: 20.0,
                                  child: TextField(
                                    decoration: InputDecoration(
                                      isDense: true,
                                      contentPadding: EdgeInsets.symmetric(
                                          vertical: 0, horizontal: 8),
                                      filled: true,
                                      fillColor: Colors.white,
                                      border: OutlineInputBorder(),
                                    ),
                                  ),
                                ),
                              ),
                              SizedBox(width: spacing),
                              Container(
                                width: dropdownWidth,
                                height: 22.0,
                                decoration: BoxDecoration(
                                  color: Colors.white,
                                  border: Border.all(color: Colors.black),
                                  borderRadius: BorderRadius.circular(4.0),
                                ),
                                child: DropdownButtonHideUnderline(
                                  child: DropdownButton<String>(
                                    value: dropdownValue,
                                    icon: Icon(Icons.arrow_downward),
                                    iconSize: 16,
                                    elevation: 16,
                                    isExpanded: true,
                                    style: TextStyle(
                                        color: Colors.black, fontSize: 12),
                                    onChanged: (String? newValue) {
                                      setState(() {
                                        dropdownValue = newValue!;
                                      });
                                    },
                                    items: <String>[
                                      'kN',
                                      'US Ton',
                                      'Metric Ton',
                                      'lb'
                                    ].map<DropdownMenuItem<String>>(
                                        (String value) {
                                      return DropdownMenuItem<String>(
                                        value: value,
                                        child: Text(value),
                                      );
                                    }).toList(),
                                  ),
                                ),
                              ),
                            ],
                          ),
                        ],
                      ),
                    ),
                  ),
                ),
                Container(
                  width: 410,
                  padding: EdgeInsets.all(8.0),
                  color: Colors.white,
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: <Widget>[
                      Text(
                        'Plain Text',
                        style: TextStyle(
                          fontSize: 12,
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                      Container(
                        width: 410,
                        height: 207,
                        decoration: BoxDecoration(
                          border: Border.all(color: Colors.black),
                          borderRadius: BorderRadius.circular(6.0),
                        ),
                        child: ClipRRect(
                          borderRadius: BorderRadius.circular(6.0),
                          child: SingleChildScrollView(
                            child: Padding(
                              padding: EdgeInsets.fromLTRB(8.0, 8.0, 16.0, 8.0),
                              child: Text(
                                upperTextBoxContent,
                                style: TextStyle(fontSize: 12),
                              ),
                            ),
                          ),
                        ),
                      ),
                      SizedBox(height: 8),
                      Text(
                        'Encoded Text',
                        style: TextStyle(
                          fontSize: 12,
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                      Container(
                        width: 410,
                        height: 132,
                        decoration: BoxDecoration(
                          border: Border.all(color: Colors.black),
                          borderRadius: BorderRadius.circular(6.0),
                        ),
                        child: ClipRRect(
                          borderRadius: BorderRadius.circular(6.0),
                          child: SingleChildScrollView(
                            child: Padding(
                              padding: EdgeInsets.fromLTRB(8.0, 8.0, 16.0, 8.0),
                              child: Text(
                                lowerTextBoxContent,
                                style: TextStyle(fontSize: 12),
                              ),
                            ),
                          ),
                        ),
                      ),
                    ],
                  ),
                ),
              ],
            ),
          ),
          Padding(
            padding: EdgeInsets.only(bottom: 10),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: <Widget>[
                ElevatedButton(
                  onPressed: () {},
                  style: ButtonStyle(
                    backgroundColor: MaterialStateProperty.all(
                        Color.fromRGBO(0, 128, 192, 1.0)),
                    foregroundColor: MaterialStateProperty.all(Colors.white),
                    shape: MaterialStateProperty.all(
                      RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(8),
                      ),
                    ),
                  ),
                  child: Text('Preview ini File'),
                ),
                ElevatedButton(
                  onPressed: () {},
                  style: ButtonStyle(
                    backgroundColor: MaterialStateProperty.all(
                        Color.fromRGBO(0, 128, 192, 1.0)),
                    foregroundColor: MaterialStateProperty.all(Colors.white),
                    shape: MaterialStateProperty.all(
                      RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(8),
                      ),
                    ),
                  ),
                  child: Text('Save ini File'),
                ),
                ElevatedButton(
                  onPressed: _loadIniFile,
                  style: ButtonStyle(
                    backgroundColor: MaterialStateProperty.all(
                        Color.fromRGBO(0, 128, 192, 1.0)),
                    foregroundColor: MaterialStateProperty.all(Colors.white),
                    shape: MaterialStateProperty.all(
                      RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(8),
                      ),
                    ),
                  ),
                  child: Text('Load ini File'),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}