FlutterでのTextFieldで日本語入力のやり方がわからない

Question

実現したいこと

Flutterでシンプルなメモアプリを作りたいので、
TextFieldを使って日本語を入力したい。

発生している問題・分からないこと

TextFieldで日本語が入力できない。
日本語の文字列のペーストはできるが、入力はできない。

該当のソースコード

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'simple_memo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // TRY THIS: Try running your application with "flutter run". You'll see
        // the application has a purple toolbar. Then, without quitting the app,
        // try changing the seedColor in the colorScheme below to Colors.green
        // and then invoke "hot reload" (save your changes or press the "hot
        // reload" button in a Flutter-supported IDE, or press "r" if you used
        // the command line to start the app).
        //
        // Notice that the counter didn't reset back to zero; the application
        // state is not lost during the reload. To reset the state, use hot
        // restart instead.
        //
        // This works for code too, not just values: Most code changes can be
        // tested with just a hot reload.
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'simple_memo'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // TRY THIS: Try changing the color here to a specific color (to
        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
        // change color while the other colors stay the same.
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: const Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          //
          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
          // action in the IDE, or press "p" in the console), to see the
          // wireframe for each widget.
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'なんか適当にメモしてね!!!!!',
            ),
            TextField(
              keyboardType: TextInputType.multiline,
              maxLines: null,
            ),
          ],
        ),
      ),
    );
  }
}

試したこと・調べたこと

• teratailやGoogle等で検索した
• ソースコードを自分なりに変更した
• 知人に聞いた
• その他

上記の詳細・結果

調べて出た情報でpubspec.yamlに
flutter_localizations:
sdk: flutter
を追加したり、
import 'package:flutter_localizations/flutter_localizations.dart';
を追加したが、変わらず。

また、return MaterialAppに
localizationsDelegates: const [
GlobalMaterialLocalizations.delegate,
GlobalWidgetsLocalizations.delegate,
GlobalCupertinoLocalizations.delegate,
],
supportedLocales: const [
Locale('ja', ''), // 日本語
Locale('en', ''), // 英語
],
を追加したが、変わらず。

補足

Windows 11 23H2
WSL 2.2.4.0
Ubuntu 22.04.3 LTS
FVM 3.1.7
Flutter 3.22.2
Dart 3.4.3

Answer 1

Flutterは知りませんが、WSL上でビルドしているようなので、WSL上のGUI(WSLg)のプログラムだと思いますが、日本語環境は整えていますか。

• WSLgの日本語入力を設定する

WSLgは、Windowsとは別のウィンドウシステムで動作しますので、日本語入力も一般的なWindowsとは別物です。
そして、デフォルトではIMEもインストールされていません。

上記の他にも、「WSLg 日本語」で検索すれば色々と出てくると思います。