Flutter開発アプリ エーオーシステム株式会社

pubspec.yaml

name: wattconversion
description: "WattConversion"
# The following line prevents the package from being accidentally published to
# pub.dev using `flutter pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number is used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
# In Windows, build-name is used as the major, minor, and patch parts
# of the product and file versions while build-number is used as the build suffix.
version: 1.1.0+7

environment:
  sdk: ^3.9.2

# Dependencies specify other packages that your package needs in order to work.
# To automatically upgrade your package dependencies to the latest versions
# consider running `flutter pub upgrade --major-versions`. Alternatively,
# dependencies can be manually updated by changing the version numbers below to
# the latest version available on pub.dev. To see which dependencies have newer
# versions available, run `flutter pub outdated`.
dependencies:
  flutter:
    sdk: flutter

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^1.0.8
  package_info_plus: ^9.0.0
  shared_preferences: ^2.0.17
  flutter_localizations:    #多言語ライブラリの本体    # .arbファイルを更新したら flutter gen-l10n
    sdk: flutter
  intl: ^0.20.2     #多言語やフォーマッタなどの関連ライブラリ
  google_mobile_ads: ^6.0.0
  just_audio: ^0.10.4

dev_dependencies:
  flutter_test:
    sdk: flutter

  flutter_launcher_icons: ^0.14.4    #flutter pub run flutter_launcher_icons
  flutter_native_splash: ^2.3.6     #flutter pub run flutter_native_splash:create

  # The "flutter_lints" package below contains a set of recommended lints to
  # encourage good coding practices. The lint set provided by the package is
  # activated in the `analysis_options.yaml` file located at the root of your
  # package. See that file for information about deactivating specific lint
  # rules and activating additional ones.
  flutter_lints: ^6.0.0

# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec

flutter_launcher_icons:
  android: "launcher_icon"
  ios: true
  image_path: "assets/icon/icon.png"
  adaptive_icon_background: "assets/icon/icon_back.png"
  adaptive_icon_foreground: "assets/icon/icon_fore.png"

flutter_native_splash:
  color: '#3dbdd0'
  image: 'assets/image/splash.png'
  color_dark: '#3dbdd0'
  image_dark: 'assets/image/splash.png'
  fullscreen: true
  android_12:
    icon_background_color: '#3dbdd0'
    image: 'assets/image/splash.png'
    icon_background_color_dark: '#3dbdd0'
    image_dark: 'assets/image/splash.png'

# The following section is specific to Flutter packages.
flutter:
  generate: true    #自動生成フラグの有効化

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #   - images/a_dot_burr.jpeg
  #   - images/a_dot_ham.jpeg

  assets:
    - assets/image/
    - assets/sound/

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.dev/to/resolution-aware-images

  # For details regarding adding assets from package dependencies, see
  # https://flutter.dev/to/asset-from-package

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.dev/to/font-from-package

lib/ad_banner_widget.dart

import 'package:flutter/cupertino.dart';
import 'package:google_mobile_ads/google_mobile_ads.dart';

import 'package:wattconversion/ad_manager.dart';

class AdBannerWidget extends StatefulWidget {
  final AdManager adManager;
  const AdBannerWidget({super.key, required this.adManager});
  @override
  State<AdBannerWidget> createState() => _AdBannerWidgetState();
}

class _AdBannerWidgetState extends State<AdBannerWidget> {
  int _lastBannerWidthDp = 0;
  bool _isAdLoaded = false;
  bool _isLoading = false;
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: LayoutBuilder(
        builder: (context, constraints) {
          final int width = constraints.maxWidth.isFinite
              ? constraints.maxWidth.truncate()
              : MediaQuery.of(context).size.width.truncate();
          final bannerAd = widget.adManager.bannerAd;
          if (width > 0) {
            WidgetsBinding.instance.addPostFrameCallback((_) {
              if (mounted) {
                final bannerAd = widget.adManager.bannerAd;
                final bool widthChanged = _lastBannerWidthDp != width;
                final bool sizeMismatch =
                    bannerAd == null || bannerAd.size.width != width;
                if ((widthChanged || !_isAdLoaded || sizeMismatch) &&
                    !_isLoading) {
                  _lastBannerWidthDp = width;
                  setState(() {
                    _isAdLoaded = false;
                    _isLoading = true;
                  });
                  widget.adManager.loadAdaptiveBannerAd(width, () {
                    if (mounted) {
                      setState(() {
                        _isAdLoaded = true;
                        _isLoading = false;
                      });
                    }
                  });
                }
              }
            });
          }
          if (_isAdLoaded && bannerAd != null) {
            return Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                SizedBox(height: 10),
                Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    SizedBox(
                      width: bannerAd.size.width.toDouble(),
                      height: bannerAd.size.height.toDouble(),
                      child: AdWidget(ad: bannerAd),
                    ),
                  ],
                )
              ]
            );
          } else {
            return const SizedBox.shrink();
          }
        },
      ),
    );
  }
}

lib/ad_manager.dart

import 'dart:async';
import 'dart:io' show Platform;
import 'dart:ui';
import 'package:google_mobile_ads/google_mobile_ads.dart';

class AdManager {
  // Test IDs
  // static const String _androidAdUnitId = "ca-app-pub-3940256099942544/6300978111";
  // static const String _iosAdUnitId     = "ca-app-pub-3940256099942544/2934735716";

  // Production IDs
  static const String _androidAdUnitId = "ca-app-pub-0/0";
  static const String _iosAdUnitId     = "ca-app-pub-0/0";

  static String get _adUnitId =>
      Platform.isIOS ? _iosAdUnitId : _androidAdUnitId;

  BannerAd? _bannerAd;
  int _lastWidthPx = 0;
  VoidCallback? _onLoadedCb;
  Timer? _retryTimer;
  int _retryAttempt = 0;

  BannerAd? get bannerAd => _bannerAd;

  Future<void> loadAdaptiveBannerAd(
    int widthPx,
    VoidCallback onAdLoaded,
  ) async {
    _onLoadedCb = onAdLoaded;
    _lastWidthPx = widthPx;
    _retryAttempt = 0;
    _retryTimer?.cancel();
    _startLoad(widthPx);
  }

  Future<void> _startLoad(int widthPx) async {
    _bannerAd?.dispose();

    AnchoredAdaptiveBannerAdSize? adaptiveSize;
    try {
      adaptiveSize =
          await AdSize.getCurrentOrientationAnchoredAdaptiveBannerAdSize(
            widthPx,
          );
    } catch (_) {
      adaptiveSize = null;
    }
    final AdSize size = adaptiveSize ?? AdSize.fullBanner;

    _bannerAd = BannerAd(
      adUnitId: _adUnitId,
      request: const AdRequest(),
      size: size,
      listener: BannerAdListener(
        onAdLoaded: (ad) {
          _retryTimer?.cancel();
          _retryAttempt = 0;
          final cb = _onLoadedCb;
          if (cb != null) {
            cb();
          }
        },
        onAdFailedToLoad: (ad, err) {
          ad.dispose();
          _scheduleRetry();
        },
      ),
    )..load();
  }

  void _scheduleRetry() {
    _retryTimer?.cancel();
    // Exponential backoff: 3s, 6s, 12s, max 30s
    _retryAttempt = (_retryAttempt + 1).clamp(1, 5);
    final seconds = _retryAttempt >= 4 ? 30 : (3 << (_retryAttempt - 1));
    _retryTimer = Timer(Duration(seconds: seconds), () {
      _startLoad(_lastWidthPx > 0 ? _lastWidthPx : 320);
    });
  }

  void dispose() {
    _bannerAd?.dispose();
    _retryTimer?.cancel();
  }
}

lib/audio_play.dart

///
/// @author akira ohmachi
/// @copyright ao-system, Inc.
/// @date 2023-01-27
///
library;

import 'package:just_audio/just_audio.dart';

import 'package:wattconversion/const_value.dart';

class AudioPlay {
  //音を重ねて連続再生できるようにインスタンスを用意しておき、順繰りに使う。
  static final List<AudioPlayer> _player01 = [
    AudioPlayer(),
    AudioPlayer(),
    AudioPlayer(),
    AudioPlayer(),
    AudioPlayer(),
    AudioPlayer(),  //6個
  ];
  int _player01Ptr = 0;

  double _soundVolume = 0.0;

  //constructor
  AudioPlay() {
    constructor();
  }
  void constructor() async {
    for (int i = 0; i < _player01.length; i++) {
      await _player01[i].setVolume(0);
      await _player01[i].setAsset(ConstValue.audioHiyoko[i]);
    }
    playZero();
  }
  void dispose() {
    for (int i = 0; i < _player01.length; i++) {
      _player01[i].dispose();
    }
  }
  //getter
  double get soundVolume {
    return _soundVolume;
  }
  //setter
  set soundVolume(double vol) {
    _soundVolume = vol;
  }
  //最初に音が鳴らないのを回避する方法
  void playZero() async {
    AudioPlayer ap = AudioPlayer();
    await ap.setAsset(ConstValue.audioZero);
    await ap.load();
    await ap.play();
  }
  //
  void play01() async {
    if (_soundVolume == 0) {
      return;
    }
    _player01Ptr += 1;
    if (_player01Ptr >= _player01.length) {
      _player01Ptr = 0;
    }
    await _player01[_player01Ptr].setVolume(_soundVolume);
    await _player01[_player01Ptr].pause();
    await _player01[_player01Ptr].seek(Duration.zero);
    await _player01[_player01Ptr].play();
  }
}

lib/const_value.dart

///
/// @author akira ohmachi
/// @copyright ao-system, Inc.
/// @date 2023-10-15
///
library;

import 'package:flutter/material.dart';

class ConstValue {
  //pref
  static const String prefLanguageCode = 'languageCode';
  static const String prefShowBackImage = 'showBackImage';
  static const String prefSoundVolume = 'soundVolume';
  static const String prefWattFrom = 'wattFrom';
  static const String prefWattTo = 'wattTo';
  static const String prefMinute = 'minute';
  static const String prefSecond = 'second';
  static const String prefThemeNumber = 'themeNumber';
  static const List<String> imageBacks = [
    'assets/image/kitchen001.webp',
    'assets/image/kitchen002.webp',
    'assets/image/kitchen003.webp',
    'assets/image/kitchen004.webp',
    'assets/image/kitchen005.webp',
    'assets/image/kitchen006.webp',
    'assets/image/kitchen007.webp',
    'assets/image/kitchen008.webp',
    'assets/image/kitchen009.webp',
    'assets/image/kitchen010.webp',
    'assets/image/kitchen011.webp',
    'assets/image/kitchen012.webp',
    'assets/image/kitchen013.webp',
    'assets/image/kitchen014.webp',
    'assets/image/kitchen015.webp',
    'assets/image/kitchen016.webp',
    'assets/image/kitchen017.webp',
    'assets/image/kitchen018.webp',
    'assets/image/kitchen019.webp',
    'assets/image/kitchen020.webp',
    'assets/image/kitchen021.webp',
    'assets/image/kitchen022.webp',
    'assets/image/kitchen023.webp',
    'assets/image/kitchen024.webp',
    'assets/image/kitchen025.webp',
    'assets/image/kitchen026.webp',
    'assets/image/kitchen027.webp',
    'assets/image/kitchen028.webp',
    'assets/image/kitchen029.webp',
    'assets/image/kitchen030.webp',
    'assets/image/kitchen031.webp',
    'assets/image/kitchen032.webp',
    'assets/image/kitchen033.webp',
    'assets/image/kitchen034.webp',
    'assets/image/kitchen035.webp',
    'assets/image/kitchen036.webp',
    'assets/image/kitchen037.webp',
    'assets/image/kitchen038.webp',
    'assets/image/kitchen039.webp',
    'assets/image/kitchen040.webp',
    'assets/image/kitchen041.webp',
    'assets/image/kitchen042.webp',
    'assets/image/kitchen043.webp',
    'assets/image/kitchen044.webp',
    'assets/image/kitchen045.webp',
    'assets/image/kitchen046.webp',
    'assets/image/kitchen047.webp',
    'assets/image/kitchen048.webp',
    'assets/image/kitchen049.webp',
    'assets/image/kitchen050.webp',
    'assets/image/kitchen051.webp',
    'assets/image/kitchen052.webp',
    'assets/image/kitchen053.webp',
    'assets/image/kitchen054.webp',
    'assets/image/kitchen055.webp',
    'assets/image/kitchen056.webp',
    'assets/image/kitchen057.webp',
    'assets/image/kitchen058.webp',
    'assets/image/kitchen059.webp',
    'assets/image/kitchen060.webp',
    'assets/image/kitchen061.webp',
    'assets/image/kitchen062.webp',
    'assets/image/kitchen063.webp',
    'assets/image/kitchen064.webp',
    'assets/image/kitchen065.webp',
    'assets/image/kitchen066.webp',
    'assets/image/kitchen067.webp',
    'assets/image/kitchen068.webp',
    'assets/image/kitchen069.webp',
    'assets/image/kitchen070.webp',
    'assets/image/kitchen071.webp',
    'assets/image/kitchen072.webp',
    'assets/image/kitchen073.webp',
    'assets/image/kitchen074.webp',
    'assets/image/kitchen075.webp',
    'assets/image/kitchen076.webp',
    'assets/image/kitchen077.webp',
    'assets/image/kitchen078.webp',
    'assets/image/kitchen079.webp',
    'assets/image/kitchen080.webp',
    'assets/image/kitchen081.webp',
    'assets/image/kitchen082.webp',
    'assets/image/kitchen083.webp',
    'assets/image/kitchen084.webp',
    'assets/image/kitchen085.webp',
    'assets/image/kitchen086.webp',
    'assets/image/kitchen087.webp',
    'assets/image/kitchen088.webp',
    'assets/image/kitchen089.webp',
    'assets/image/kitchen090.webp',
    'assets/image/kitchen091.webp',
    'assets/image/kitchen092.webp',
    'assets/image/kitchen093.webp',
    'assets/image/kitchen094.webp',
    'assets/image/kitchen095.webp',
    'assets/image/kitchen096.webp',
    'assets/image/kitchen097.webp',
    'assets/image/kitchen098.webp',
    'assets/image/kitchen099.webp',
    'assets/image/kitchen100.webp',
    'assets/image/kitchen101.webp',
    'assets/image/kitchen102.webp',
    'assets/image/kitchen103.webp',
    'assets/image/kitchen104.webp',
    'assets/image/kitchen105.webp',
    'assets/image/kitchen106.webp',
    'assets/image/kitchen107.webp',
    'assets/image/kitchen108.webp',
    'assets/image/kitchen109.webp',
    'assets/image/kitchen110.webp',
    'assets/image/kitchen111.webp',
    'assets/image/kitchen112.webp',
    'assets/image/kitchen113.webp',
    'assets/image/kitchen114.webp',
    'assets/image/kitchen115.webp',
    'assets/image/kitchen116.webp',
    'assets/image/kitchen117.webp',
    'assets/image/kitchen118.webp',
    'assets/image/kitchen119.webp',
    'assets/image/kitchen120.webp',
    'assets/image/kitchen121.webp',
    'assets/image/kitchen122.webp',
    'assets/image/kitchen123.webp',
    'assets/image/kitchen124.webp',
    'assets/image/kitchen125.webp',
    'assets/image/kitchen126.webp',
    'assets/image/kitchen127.webp',
    'assets/image/kitchen128.webp',
    'assets/image/kitchen129.webp',
    'assets/image/kitchen130.webp',
    'assets/image/kitchen131.webp',
    'assets/image/kitchen132.webp',
    'assets/image/kitchen133.webp',
    'assets/image/kitchen134.webp',
    'assets/image/kitchen135.webp',
    'assets/image/kitchen136.webp',
    'assets/image/kitchen137.webp',
    'assets/image/kitchen138.webp',
    'assets/image/kitchen139.webp',
    'assets/image/kitchen140.webp',
    'assets/image/kitchen141.webp',
    'assets/image/kitchen142.webp',
    'assets/image/kitchen143.webp',
    'assets/image/kitchen144.webp',
    'assets/image/kitchen145.webp',
    'assets/image/kitchen146.webp',
    'assets/image/kitchen147.webp',
    'assets/image/kitchen148.webp',
    'assets/image/kitchen149.webp',
    'assets/image/kitchen150.webp',
    'assets/image/kitchen151.webp',
    'assets/image/kitchen152.webp',
    'assets/image/kitchen153.webp',
    'assets/image/kitchen154.webp',
    'assets/image/kitchen155.webp',
    'assets/image/kitchen156.webp',
    'assets/image/kitchen157.webp',
    'assets/image/kitchen158.webp',
    'assets/image/kitchen159.webp',
    'assets/image/kitchen160.webp',
    'assets/image/kitchen161.webp',
    'assets/image/kitchen162.webp',
    'assets/image/kitchen163.webp',
    'assets/image/kitchen164.webp',
    'assets/image/kitchen165.webp',
    'assets/image/kitchen166.webp',
    'assets/image/kitchen167.webp',
    'assets/image/kitchen168.webp',
    'assets/image/kitchen169.webp',
    'assets/image/kitchen170.webp',
    'assets/image/kitchen171.webp',
    'assets/image/kitchen172.webp',
    'assets/image/kitchen173.webp',
    'assets/image/kitchen174.webp',
    'assets/image/kitchen175.webp',
    'assets/image/kitchen176.webp',
    'assets/image/kitchen177.webp',
    'assets/image/kitchen178.webp',
    'assets/image/kitchen179.webp',
    'assets/image/kitchen180.webp',
    'assets/image/kitchen181.webp',
    'assets/image/kitchen182.webp',
    'assets/image/kitchen183.webp',
    'assets/image/kitchen184.webp',
    'assets/image/kitchen185.webp',
    'assets/image/kitchen186.webp',
    'assets/image/kitchen187.webp',
    'assets/image/kitchen188.webp',
    'assets/image/kitchen189.webp',
    'assets/image/kitchen190.webp',
    'assets/image/kitchen191.webp',
    'assets/image/kitchen192.webp',
    'assets/image/kitchen193.webp',
    'assets/image/kitchen194.webp',
    'assets/image/kitchen195.webp',
    'assets/image/kitchen196.webp',
    'assets/image/kitchen197.webp',
    'assets/image/kitchen198.webp',
    'assets/image/kitchen199.webp',
    'assets/image/kitchen200.webp',
  ];
  //color
  static const Color colorMainHeader = Color.fromRGBO(0,0,0,0.4);
  static const Color colorMainBack = Color.fromRGBO(220, 220, 220, 1);
  static const Color colorMainUiActiveColorFrom = Color.fromRGBO(255,30,80,1);
  static const Color colorMainUiActiveColorTo = Color.fromRGBO(120,120,255,1);
  static const Color colorSettingUiActiveColor = Colors.deepPurple;
  static const Color colorUiInactiveColor = Color.fromRGBO(50,50,50,1);
  //sound
  static const String audioZero = 'assets/sound/zero.wav';    //無音1秒
  static const List<String> audioHiyoko = [
    'assets/sound/hiyoko1.wav',
    'assets/sound/hiyoko2.wav',
    'assets/sound/hiyoko3.wav',
    'assets/sound/hiyoko4.wav',
    'assets/sound/hiyoko5.wav',
    'assets/sound/hiyoko6.wav',
  ];

}

lib/empty.dart

lib/language_support.dart

///
/// Consolidated language utilities.
///
library;

/// Usage:
///   await LanguageState.ensureInitialized();
///   final currentCode = await LanguageState.getLanguageCode();
///   await LanguageState.setLanguageCode('en');
///   final locale = parseLocaleTag(currentCode);
///
/// Use LanguageCatalog when presenting selectable language names.
/// Configure LanguageState.configure if you need custom storage.
///

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';

class LanguageCatalog {
  const LanguageCatalog._();

  static const String prefLanguageCode = 'languageCode';

  static const Map<String, String> names = {
    'en': 'English',
    'bg': 'Български',
    'cs': 'Čeština',
    'da': 'Dansk',
    'de': 'Deutsch',
    'el': 'Ελληνικά',
    'es': 'Español',
    'et': 'Eesti',
    'fi': 'Suomi',
    'fr': 'Français',
    'hu': 'Magyar',
    'it': 'Italiano',
    'ja': '日本語',
    'lt': 'Lietuvių',
    'lv': 'Latviešu',
    'nl': 'Nederlands',
    'pl': 'Polski',
    'pt': 'Português',
    'ro': 'Română',
    'ru': 'Русский',
    'sk': 'Slovenčina',
    'sv': 'Svenska',
    'th': 'ไทย',
    'zh': '中文',
  };

  static List<String> get supportedCodes => names.keys.toList(growable: false);

  static List<Locale> buildSupportedLocales() {
    return supportedCodes.map((code) => Locale(code)).toList(growable: false);
  }

  static String labelFor(String? code) {
    if (code == null || code.isEmpty) {
      return 'Default';
    }
    return names[code] ?? code;
  }
}

abstract class LanguageStorage {
  const LanguageStorage();

  Future<void> saveLanguageCode(String code);

  Future<String> loadLanguageCode();
}

class SharedPreferencesLanguageStorage extends LanguageStorage {
  const SharedPreferencesLanguageStorage({
    this.prefLanguageCode = LanguageCatalog.prefLanguageCode,
  });

  final String prefLanguageCode;

  Future<SharedPreferences> _ensurePrefs() async {
    return SharedPreferences.getInstance();
  }

  @override
  Future<void> saveLanguageCode(String code) async {
    final prefs = await _ensurePrefs();
    await prefs.setString(prefLanguageCode, code);
  }

  @override
  Future<String> loadLanguageCode() async {
    final prefs = await _ensurePrefs();
    return prefs.getString(prefLanguageCode) ?? '';
  }
}

class LanguageState {
  LanguageState._();

  static LanguageStorage _storage = const SharedPreferencesLanguageStorage();
  static String _languageCode = '';
  static bool _initialized = false;
  static Completer<void>? _initializing;

  static String get currentCode => _languageCode;

  static void configure({LanguageStorage? storage, String? initialCode}) {
    if (storage != null) {
      _storage = storage;
    }
    if (initialCode != null) {
      _languageCode = initialCode;
      _initialized = true;
    }
  }

  static Future<void> ensureInitialized() async {
    if (_initialized) {
      return;
    }
    final completer = _initializing;
    if (completer != null) {
      await completer.future;
      return;
    }
    final newCompleter = Completer<void>();
    _initializing = newCompleter;
    try {
      _languageCode = await _storage.loadLanguageCode();
      _initialized = true;
      newCompleter.complete();
    } catch (error, stackTrace) {
      if (!newCompleter.isCompleted) {
        newCompleter.completeError(error, stackTrace);
      }
      rethrow;
    } finally {
      _initializing = null;
    }
  }

  static Future<void> setLanguageCode(String? code) async {
    final value = code?.trim() ?? '';
    _languageCode = value;
    _initialized = true;
    await _storage.saveLanguageCode(value);
  }

  static Future<String> getLanguageCode() async {
    await ensureInitialized();
    return _languageCode;
  }
}

Locale? parseLocaleTag(String tag) {
  if (tag.isEmpty) {
    return null;
  }
  final parts = tag.split('-');
  final language = parts.isNotEmpty ? parts[0] : tag;
  String? script;
  String? country;
  if (parts.length >= 2) {
    final p1 = parts[1];
    if (p1.length == 4) {
      script = p1;
    } else {
      country = p1;
    }
  }
  if (parts.length >= 3) {
    final p2 = parts[2];
    if (p2.length == 4) {
      script = p2;
    } else {
      country = p2;
    }
  }
  return Locale.fromSubtags(
    languageCode: language,
    scriptCode: script,
    countryCode: country,
  );
}

lib/loading_screen.dart

import 'package:flutter/material.dart';

class LoadingScreen extends StatelessWidget {
  const LoadingScreen({super.key});
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.indigo,
      body: const Center(
        child: CircularProgressIndicator(
          valueColor: AlwaysStoppedAnimation<Color>(Colors.indigoAccent),
          backgroundColor: Colors.white,
        ),
      ),
    );
  }
}

lib/main.dart

///
/// @author akira ohmachi
/// @copyright ao-system, Inc.
/// @date 2023-10-02
///
library;

import 'package:flutter/material.dart';
import 'package:package_info_plus/package_info_plus.dart';
import 'l10n/app_localizations.dart';
import 'package:google_mobile_ads/google_mobile_ads.dart' if (dart.library.html) 'empty.dart';
import 'package:flutter/foundation.dart' show kIsWeb;

import 'package:wattconversion/language_support.dart';
import 'package:wattconversion/const_value.dart';
import 'package:wattconversion/version_state.dart';
import 'package:wattconversion/setting.dart';
import 'package:wattconversion/ad_manager.dart';
import 'package:wattconversion/ad_banner_widget.dart';
import 'package:wattconversion/preferences.dart';
import 'package:wattconversion/audio_play.dart';
import 'package:wattconversion/loading_screen.dart';
import 'package:wattconversion/theme_color.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  if (!kIsWeb) {
    MobileAds.instance.initialize();
  }
  await Preferences.initial();
  await LanguageState.ensureInitialized();
  runApp(const MainApp());
}

ThemeMode _themeModeFromNumber(int value) {
  switch (value) {
    case 1:
      return ThemeMode.light;
    case 2:
      return ThemeMode.dark;
    default:
      return ThemeMode.system;
  }
}

class MainApp extends StatefulWidget {    //statefulに変更して言語変更に対応
  const MainApp({super.key});
  @override
  State<MainApp> createState() => _MainAppState();
}

class _MainAppState extends State<MainApp> {
  Locale? localeLanguage;
  ThemeMode themeMode = ThemeMode.system;
  @override
  void initState() {
    super.initState();
    localeLanguage = parseLocaleTag(LanguageState.currentCode);
    themeMode = _themeModeFromNumber(Preferences.themeNumber);
  }
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      localizationsDelegates: AppLocalizations.localizationsDelegates,   //多言語化
      supportedLocales: AppLocalizations.supportedLocales,  //自動で言語リストを生成
      locale: localeLanguage,
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: ConstValue.colorMainBack),
        useMaterial3: true,
      ),
      darkTheme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
          seedColor: ConstValue.colorMainBack,
          brightness: Brightness.dark,
        ),
        useMaterial3: true,
      ),
      themeMode: themeMode,
      home: const MainHomePage(),
    );
  }
}

class MainHomePage extends StatefulWidget {
  const MainHomePage({super.key});
  @override
  State<MainHomePage> createState() => _MainHomePageState();
}

class _MainHomePageState extends State<MainHomePage> with SingleTickerProviderStateMixin {
  late AdManager _adManager;
  late ThemeColor _themeColor;
  final AudioPlay _audioPlay = AudioPlay(); //効果音
  late AnimationController _animationController;
  late Animation<double> _opacityAnimation;
  bool _showBackImage = true;
  int _backImageNumber = 0;
  int _lastBackImageNumber = 0;
  int _wattFrom = 600;
  int _wattTo = 500;
  int _minute = 5;
  int _second = 0;
  int _themeNumber = 0;
  bool _isReady = false;
  bool _isFirst = true;

  //アプリのバージョン取得
  void _getVersion() async {
    PackageInfo packageInfo = await PackageInfo.fromPlatform();
    setState(() {
      VersionState.versionSave(packageInfo.version);
    });
  }
  //言語準備
  Future<void> _getCurrentLocale() async {
    final String code = await LanguageState.getLanguageCode();
    if (!mounted) {
      return;
    }
    final mainState = context.findAncestorStateOfType<_MainAppState>();
    if (mainState == null) {
      return;
    }
    mainState
      ..localeLanguage = parseLocaleTag(code)
      ..setState(() {});
  }
  //Theme
  void _getThemeColor() {
    _themeColor = ThemeColor(themeNumber: _themeNumber, context: context);
  }
  void _applyThemeMode() {
    final mainState = context.findAncestorStateOfType<_MainAppState>();
    if (mainState == null) {
      return;
    }
    mainState
      ..themeMode = _themeModeFromNumber(Preferences.themeNumber)
      ..setState(() {});
  }

  @override
  void initState() {
    super.initState();
    _initState();
  }

  void _initState() async {
    _getVersion();
    _getCurrentLocale();
    LanguageState.getLanguageCode();
    _adManager = AdManager();
    _audioPlay.playZero();
    final int subSecond = (DateTime.now()).millisecondsSinceEpoch ~/ 100;
    _backImageNumber = subSecond % ConstValue.imageBacks.length;
    //background animation
    _animationController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 500),
    );
    _opacityAnimation = Tween<double>(begin: 0, end: 1).animate(_animationController);
    _animationController.addListener(() {
      setState(() {});
    });
    _backImageChange();
    //
    await Preferences.initial();
    _showBackImage = Preferences.showBackImage;
    _audioPlay.soundVolume = Preferences.soundVolume;
    _wattFrom = Preferences.wattFrom;
    _wattTo = Preferences.wattTo;
    _minute = Preferences.minute;
    _second = Preferences.second;
    _themeNumber = Preferences.themeNumber;
    _applyThemeMode();
    setState(() {
      _isReady = true;
    });
  }

  @override
  void dispose() {
    _adManager.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    if (_isReady == false) {
      return const LoadingScreen();
    }
    if (_isFirst) {
      _isFirst = false;
      _getThemeColor();
    }
    return Container(
      decoration: const BoxDecoration(
        color: ConstValue.colorMainBack,
      ),
      child: Container(
        decoration: _decoration2(),
        child: Container(
          decoration: _decoration1(),
          child: Scaffold(
            backgroundColor: Colors.transparent, //ここは透明
            appBar: AppBar(
              backgroundColor: ConstValue.colorMainHeader,
              //タイトル表示
              title: Text(AppLocalizations.of(context)!.title,
                style: const TextStyle(
                  color: Colors.white,
                  fontSize: 12.0,
                )
              ),
              //設定ボタン
              actions: <Widget>[
                TextButton(
                  onPressed: () async {
                    bool? ret = await Navigator.of(context).push(
                      MaterialPageRoute<bool>(builder:(context) => const SettingPage()),
                    );
                    //awaitで呼び出しているので、settingから戻ったら以下が実行される。
                    if (ret!) { //設定で適用だった場合
                      await _getCurrentLocale();
                      _showBackImage = Preferences.showBackImage;
                      _audioPlay.soundVolume = Preferences.soundVolume;
                      _themeNumber = Preferences.themeNumber;
                      _getThemeColor();
                      _applyThemeMode();
                      setState(() {});
                    }
                  },
                  child: Text(
                    AppLocalizations.of(context)!.setting,
                    style: const TextStyle(
                      color: Colors.white,
                      fontSize: 12.0,
                    )
                  )
                )
              ]
            ),
            body: SafeArea(
              child: GestureDetector(
                onTap: () {
                  _audioPlay.play01();
                  _backImageChange();
                },
                child: Column(children: [
                  Expanded(
                    child: SingleChildScrollView(
                      child: Padding(
                        padding: const EdgeInsets.only(top: 5, left: 5, right: 5, bottom: 100),
                        child: Column(children: [
                          _content(),
                        ])
                      )
                    )
                  ),
                ])
              )
            ),
            bottomNavigationBar: AdBannerWidget(adManager: _adManager),
          )
        )
      )
    );
  }
  //背景画像前側
  Decoration _decoration1() {
    if (_showBackImage) {
      return BoxDecoration(
        image: DecorationImage(
          image: AssetImage(ConstValue.imageBacks[_backImageNumber]),
          fit: BoxFit.cover,
          colorFilter: ColorFilter.mode(
            Colors.black.withValues(alpha: _opacityAnimation.value),
            BlendMode.dstATop,
          ),
        )
      );
    } else {
      return const BoxDecoration();
    }
  }
  //背景画像後ろ側
  Decoration _decoration2() {
    if (_showBackImage) {
      return BoxDecoration(
        image: DecorationImage(
          image: AssetImage(ConstValue.imageBacks[_lastBackImageNumber]),
          fit: BoxFit.cover,
        ),
      );
    } else {
      return const BoxDecoration();
    }
  }
  void _backImageChange() {
    final int subSecond = (DateTime.now()).millisecondsSinceEpoch ~/ 100;
    _backImageNumber = subSecond % ConstValue.imageBacks.length;
    _animationController.forward();
    Future.delayed(const Duration(milliseconds: 600), () {
      _lastBackImageNumber = _backImageNumber;
      _animationController.reverse();
    });
  }

  Widget _content() {
    return Column(children:[
      _widgetWattFrom(),
      _widgetMinute(),
      _widgetSecond(),
      _widgetWattTo(),
      _widgetResult(),
    ]);
  }

  Widget _widgetWattFrom() {
    final l = AppLocalizations.of(context)!;
    return SizedBox(
      width: double.infinity,
      child: Card(
        margin: const EdgeInsets.only(left: 4, top: 4, right: 4, bottom: 0),
        color: _themeColor.backColorMono.withValues(alpha: 0.9),
        elevation: 0,
        shadowColor: Colors.transparent,
        surfaceTintColor: Colors.transparent,
        shape: const RoundedRectangleBorder(
          borderRadius: BorderRadius.only(
            topLeft: Radius.circular(12),
            topRight: Radius.circular(12),
            bottomLeft: Radius.circular(0),
            bottomRight: Radius.circular(0),
          ),
        ),
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children:[
              Padding(
                padding: const EdgeInsets.only(top: 5, left: 10, right: 0, bottom: 0),
                child: Row(children: [
                  Text(l.wattFrom),
                  const Spacer(),
                ])
              ),
              Padding(
                padding: const EdgeInsets.only(top: 0, left: 10, right: 0, bottom: 0),
                child: Row(children: <Widget>[
                  Container(
                    color: _themeColor.backColorMono,
                    child: SizedBox(
                      width: 80,
                      child: Text(_wattFrom.toString(),textAlign: TextAlign.center,
                        style: Theme.of(context).textTheme.titleLarge
                      ),
                    )
                  ),
                  Expanded(
                    child: Slider(
                      value: _wattFrom.toDouble(),
                      min: 300,
                      max: 1800,
                      divisions: 15,
                      onChanged: (double value) {
                        setState(() {
                          _wattFrom = value.toInt();
                          Preferences.setWattFrom(_wattFrom);
                        });
                      },
                      activeColor: ConstValue.colorMainUiActiveColorFrom,
                      inactiveColor: ConstValue.colorUiInactiveColor,
                    )
                  )
                ])
              )
            ]
          ),
        ),
      )
    );
  }

  Widget _widgetMinute() {
    final l = AppLocalizations.of(context)!;
    return SizedBox(
      width: double.infinity,
      child: Card(
        margin: const EdgeInsets.only(left: 4, top: 3, right: 4, bottom: 0),
        color: _themeColor.backColorMono.withValues(alpha: 0.9),
        elevation: 0,
        shadowColor: Colors.transparent,
        surfaceTintColor: Colors.transparent,
        shape: const RoundedRectangleBorder(
          borderRadius: BorderRadius.only(
            topLeft: Radius.circular(0),
            topRight: Radius.circular(0),
            bottomLeft: Radius.circular(0),
            bottomRight: Radius.circular(0),
          ),
        ),
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children:[
              Padding(
                padding: const EdgeInsets.only(top: 5, left: 10, right: 0, bottom: 0),
                child: Row(children: [
                  Text(l.fromMinute),
                  const Spacer(),
                ])
              ),
              Padding(
                padding: const EdgeInsets.only(top: 0, left: 10, right: 0, bottom: 0),
                child: Row(children: <Widget>[
                  Container(
                    color: _themeColor.backColorMono,
                    child: SizedBox(
                      width: 80,
                      child: Text(_minute.toString(),textAlign: TextAlign.center,
                        style: Theme.of(context).textTheme.titleLarge
                      ),
                    )
                  ),
                  Expanded(
                    child: Slider(
                      value: _minute.toDouble(),
                      min: 1,
                      max: 30,
                      divisions: 29,
                      onChanged: (double value) {
                        setState(() {
                          _minute = value.toInt();
                          Preferences.setMinute(_minute);
                        });
                      },
                      activeColor: ConstValue.colorMainUiActiveColorFrom,
                      inactiveColor: ConstValue.colorUiInactiveColor,
                    )
                  )
                ])
              )
            ]
          ),
        ),
      )
    );
  }

  Widget _widgetSecond() {
    final l = AppLocalizations.of(context)!;
    return SizedBox(
      width: double.infinity,
      child: Card(
        margin: const EdgeInsets.only(left: 4, top: 3, right: 4, bottom: 0),
        color: _themeColor.backColorMono.withValues(alpha: 0.9),
        elevation: 0,
        shadowColor: Colors.transparent,
        surfaceTintColor: Colors.transparent,
        shape: const RoundedRectangleBorder(
          borderRadius: BorderRadius.only(
            topLeft: Radius.circular(0),
            topRight: Radius.circular(0),
            bottomLeft: Radius.circular(12),
            bottomRight: Radius.circular(12),
          ),
        ),
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children:[
              Padding(
                padding: const EdgeInsets.only(top: 5, left: 10, right: 0, bottom: 0),
                child: Row(children: [
                  Text(l.fromSecond),
                  const Spacer(),
                ])
              ),
              Padding(
                padding: const EdgeInsets.only(top: 0, left: 10, right: 0, bottom: 0),
                child: Row(children: <Widget>[
                  Container(
                    color: _themeColor.backColorMono,
                    child: SizedBox(
                      width: 80,
                      child: Text(_second.toString(),textAlign: TextAlign.center,
                        style: Theme.of(context).textTheme.titleLarge
                      ),
                    )
                  ),
                  Expanded(
                    child: Slider(
                      value: _second.toDouble(),
                      min: 0,
                      max: 50,
                      divisions: 5,
                      onChanged: (double value) {
                        setState(() {
                          _second = value.toInt();
                          Preferences.setMinute(_second);
                        });
                      },
                      activeColor: ConstValue.colorMainUiActiveColorFrom,
                      inactiveColor: ConstValue.colorUiInactiveColor,
                    )
                  )
                ])
              )
            ]
          ),
        ),
      )
    );
  }

  Widget _widgetWattTo() {
    final l = AppLocalizations.of(context)!;
    return SizedBox(
      width: double.infinity,
      child: Card(
        margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
        color: _themeColor.backColorMono.withValues(alpha: 0.9),
        elevation: 0,
        shadowColor: Colors.transparent,
        surfaceTintColor: Colors.transparent,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children:[
              Padding(
                padding: const EdgeInsets.only(top: 5, left: 10, right: 0, bottom: 0),
                child: Row(children: [
                  Text(l.wattTo),
                  const Spacer(),
                ])
              ),
              Padding(
                padding: const EdgeInsets.only(top: 0, left: 10, right: 0, bottom: 0),
                child: Row(children: <Widget>[
                  Container(
                    color: _themeColor.backColorMono,
                    child: SizedBox(
                      width: 80,
                      child: Text(_wattTo.toString(),textAlign: TextAlign.center,
                        style: Theme.of(context).textTheme.titleLarge
                      ),
                    )
                  ),
                  Expanded(
                    child: Slider(
                      value: _wattTo.toDouble(),
                      min: 300,
                      max: 1800,
                      divisions: 15,
                      onChanged: (double value) {
                        setState(() {
                          _wattTo = value.toInt();
                          Preferences.setWattTo(_wattTo);
                        });
                      },
                      activeColor: ConstValue.colorMainUiActiveColorTo,
                      inactiveColor: ConstValue.colorUiInactiveColor,
                    )
                  )
                ])
              ),
            ]
          ),
        ),
      )
    );
  }

  Widget _widgetResult() {
    final l = AppLocalizations.of(context)!;
    final int sec = ((_minute * 60 + _second) / _wattTo * _wattFrom).toInt();
    final int answerMinute = (sec / 60).floor();
    final int answerSecond = sec % 60;
    return SizedBox(
      width: double.infinity,
      child: Card(
        margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
        color: _themeColor.backColorMono.withValues(alpha: 0.9),
        elevation: 0,
        shadowColor: Colors.transparent,
        surfaceTintColor: Colors.transparent,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children:[
              Row(children: [
                const Spacer(),
                Text('${l.specified} ${_wattFrom}W',
                  style: TextStyle(
                    color: ConstValue.colorMainUiActiveColorFrom,
                    fontSize: Theme.of(context).textTheme.titleLarge?.fontSize,
                  )
                ),
                const Spacer(),
              ]),
              Row(children: [
                const Spacer(),
                Text('${_minute} ${l.minute} ${_second} ${l.second}',
                    style: TextStyle(
                      color: ConstValue.colorMainUiActiveColorFrom,
                      fontSize: Theme.of(context).textTheme.titleLarge?.fontSize,
                    )
                ),
                const Spacer(),
              ]),
              SizedBox(height: 5),
              Row(children: [
                const Spacer(),
                Text('${l.conversion} ${_wattTo}W',
                  style: TextStyle(
                    color: ConstValue.colorMainUiActiveColorTo,
                    fontSize: Theme.of(context).textTheme.titleLarge?.fontSize,
                  )
                ),
                const Spacer(),
              ]),
              Row(children: [
                const Spacer(),
                Text('${answerMinute} ${l.minute} ${answerSecond} ${l.second}',
                  style: TextStyle(
                    color: ConstValue.colorMainUiActiveColorTo,
                    fontSize: Theme.of(context).textTheme.titleLarge?.fontSize,
                  ),
                ),
                const Spacer(),
              ])
            ]
          ),
        ),
      )
    );
  }

}

lib/preferences.dart

///
/// @author akira ohmachi
/// @copyright ao-system, Inc.
/// @date 2023-10-26
///
library;

import 'package:shared_preferences/shared_preferences.dart';

import 'package:wattconversion/const_value.dart';

//デバイスに情報を保存
class Preferences {

  static bool ready = false;
  //この値は常に最新にしておく
  static String _languageCode = '';
  static bool _showBackImage = true;
  static double _soundVolume = 0.3;
  static int _wattFrom = 600;
  static int _wattTo = 500;
  static int _minute = 5;
  static int _second = 0;
  static int _themeNumber = 0;

  static String get languageCode => _languageCode;
  static bool get showBackImage => _showBackImage;
  static double get soundVolume => _soundVolume;
  static int get wattFrom => _wattFrom;
  static int get wattTo => _wattTo;
  static int get minute => _minute;
  static int get second => _second;
  static int get themeNumber => _themeNumber;

  static Future<void> initial() async {
    _languageCode = await getLanguageCode();
    _showBackImage = await getShowBackImage();
    _soundVolume = await getSoundVolume();
    _wattFrom = await getWattFrom();
    _wattTo = await getWattTo();
    _minute = await getMinute();
    _second = await getSecond();
    _themeNumber = await getThemeNumber();
    ready = true;
  }

  //----------------------------

  //言語コード
  static Future<void> setLanguageCode(String str) async {
    _languageCode = str;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setString(ConstValue.prefLanguageCode, str);
  }
  static Future<String> getLanguageCode() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final String str = prefs.getString(ConstValue.prefLanguageCode) ?? 'en';
    return str;
  }

  //----------------------------

  //背景画像表示
  static Future<void> setShowBackImage(bool flag) async {
    _showBackImage = flag;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setBool(ConstValue.prefShowBackImage, flag);
  }
  static Future<bool> getShowBackImage() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final bool flag = prefs.getBool(ConstValue.prefShowBackImage) ?? true;
    return flag;
  }

  //----------------------------

  //効果音音量
  static Future<void> setSoundVolume(double num) async {
    _soundVolume = num;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setDouble(ConstValue.prefSoundVolume, num);
  }
  static Future<double> getSoundVolume() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final double num = prefs.getDouble(ConstValue.prefSoundVolume) ?? 0.3;
    return num;
  }

  //----------------------------

  //watt from
  static Future<void> setWattFrom(int num) async {
    _wattFrom = num;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setInt(ConstValue.prefWattFrom, num);
  }
  static Future<int> getWattFrom() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int num = prefs.getInt(ConstValue.prefWattFrom) ?? 600;
    return num;
  }

  //----------------------------

  //watt to
  static Future<void> setWattTo(int num) async {
    _wattTo = num;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setInt(ConstValue.prefWattTo, num);
  }
  static Future<int> getWattTo() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int num = prefs.getInt(ConstValue.prefWattTo) ?? 500;
    return num;
  }
  //----------------------------

  //minute
  static Future<void> setMinute(int num) async {
    _minute = num;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setInt(ConstValue.prefMinute, num);
  }
  static Future<int> getMinute() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int num = prefs.getInt(ConstValue.prefMinute) ?? 5;
    return num;
  }

  //----------------------------

  //second
  static Future<void> setSecond(int num) async {
    _second = num;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setInt(ConstValue.prefSecond, num);
  }
  static Future<int> getSecond() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int num = prefs.getInt(ConstValue.prefSecond) ?? 0;
    return num;
  }

  //----------------------------

  //themeNumber
  static Future<void> setThemeNumber(int num) async {
    _themeNumber = num;
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    await prefs.setInt(ConstValue.prefThemeNumber, num);
  }
  static Future<int> getThemeNumber() async {
    final SharedPreferences prefs = await SharedPreferences.getInstance();
    final int num = prefs.getInt(ConstValue.prefThemeNumber) ?? 0;
    return num;
  }

  //----------------------------

}

lib/setting.dart

///
/// @author akira ohmachi
/// @copyright ao-system, Inc.
/// @date 2023-10-15
///
library;

import 'package:flutter/material.dart';
import 'l10n/app_localizations.dart';

import 'package:wattconversion/language_support.dart';
import 'package:wattconversion/preferences.dart';
import 'package:wattconversion/const_value.dart';
import 'package:wattconversion/version_state.dart';
import 'package:wattconversion/ad_manager.dart';
import 'package:wattconversion/ad_banner_widget.dart';
import 'package:wattconversion/loading_screen.dart';
import 'package:wattconversion/theme_color.dart';

class SettingPage extends StatefulWidget {
  const SettingPage({super.key});
  @override
  State<SettingPage> createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  String? _languageKey;
  late AdManager _adManager;
  late ThemeColor _themeColor;
  bool _showBackImage = true;
  double _soundVolume = 0.0;
  int _themeNumber = 0;
  bool _isReady = false;
  bool _isFirst = true;

  @override
  void initState() {
    super.initState();
    _initState();
  }

  void _initState() async {
    _adManager = AdManager();
    final String languageCode = await LanguageState.getLanguageCode();
    if (!mounted) {
      return;
    }
    _languageKey = languageCode.isEmpty ? null : languageCode;
    await Preferences.initial();
    if (!mounted) {
      return;
    }
    _showBackImage = Preferences.showBackImage;
    _soundVolume = Preferences.soundVolume;
    _themeNumber = Preferences.themeNumber;
    setState(() {
      _isReady = true;
    });
  }

  @override
  void dispose() {
    _adManager.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    if (_isReady == false) {
      return LoadingScreen();
    }
    if (_isFirst) {
      _isFirst = false;
      _themeColor = ThemeColor(themeNumber: _themeNumber, context: context);
    }
    final l = AppLocalizations.of(context)!;
    return Scaffold(
      backgroundColor: _themeColor.backColor,
      appBar: AppBar(
        centerTitle: true,
        elevation: 0,
        leading: IconButton(
          icon: const Icon(Icons.close),
          onPressed: () {
            Navigator.of(context).pop(false);
          },
        ),
        title: Text(l.setting),
        foregroundColor: _themeColor.appBarForegroundColor,
        backgroundColor: Colors.transparent,
        actions: [
          IconButton(
            icon: const Icon(Icons.check),
            onPressed: () async {
              await LanguageState.setLanguageCode(_languageKey);
              await Preferences.setShowBackImage(_showBackImage);
              await Preferences.setSoundVolume(_soundVolume);
              await Preferences.setThemeNumber(_themeNumber);
              if (!mounted) {
                return;
              }
              Navigator.of(context).pop(true);
            },
          ),
        ],
      ),
      body: Column(children:[
        Expanded(
          child: GestureDetector(
            onTap: () => FocusScope.of(context).unfocus(),  //背景タップでキーボードを仕舞う
            child: SingleChildScrollView(
              child: Padding(
                padding: const EdgeInsets.only(left: 4, top: 4, right: 4, bottom: 100),
                child: Column(children: [
                  _buildBackgroundImage(),
                  _buildVolume(),
                  _buildLanguage(),
                  _buildTheme(),
                  _buildUsage(),
                  _buildVersion(),
                ]),
              ),
            ),
          ),
        ),
      ]),
      bottomNavigationBar: AdBannerWidget(adManager: _adManager),
    );
  }

  Widget _buildBackgroundImage() {
    final l = AppLocalizations.of(context)!;
    return Card(
      margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
      color: _themeColor.cardColor,
      elevation: 0,
      shadowColor: Colors.transparent,
      surfaceTintColor: Colors.transparent,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Padding(
            padding: const EdgeInsets.only(top: 16, left: 16, right: 16, bottom: 16),
            child: Row(children:<Widget>[
              Expanded(child: Text(l.showBackImage)),
              Switch(
                value: _showBackImage,
                onChanged: (bool value) {
                  setState(() {
                    _showBackImage = value;
                  });
                },
                activeThumbColor: ConstValue.colorSettingUiActiveColor,
                inactiveThumbColor: ConstValue.colorUiInactiveColor,
              ),
            ]),
          ),
        ],
      ),
    );
  }

  Widget _buildVolume() {
    final l = AppLocalizations.of(context)!;
    return Card(
      margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
      color: _themeColor.cardColor,
      elevation: 0,
      shadowColor: Colors.transparent,
      surfaceTintColor: Colors.transparent,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Padding(
            padding: const EdgeInsets.only(top: 18, left: 16, right: 16, bottom: 0),
            child: Row(children: [
              Text(l.soundVolume),
              const Spacer(),
            ])
          ),
          Padding(
            padding: const EdgeInsets.only(top: 0, left: 16, right: 16, bottom: 6),
            child: Row(children: <Widget>[
              Text(_soundVolume.toString()),
              Expanded(
                child: Slider(
                  value: _soundVolume,
                  min: 0.0,
                  max: 1.0,
                  divisions: 10,
                  onChanged: (double value) {
                    setState(() {
                      _soundVolume = value;
                    });
                  },
                  activeColor: ConstValue.colorSettingUiActiveColor,
                  inactiveColor: ConstValue.colorUiInactiveColor,
                )
              )
            ])
          ),
        ],
      ),
    );
  }

  Widget _buildLanguage() {
    final l = AppLocalizations.of(context)!;
    return Card(
      margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
      color: _themeColor.cardColor,
      elevation: 0,
      shadowColor: Colors.transparent,
      surfaceTintColor: Colors.transparent,
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            ListTile(
              title: Text(l.language,style: Theme.of(context).textTheme.bodyMedium),
              contentPadding: const EdgeInsets.symmetric(horizontal: 0),
              trailing: DropdownButton<String?>(
                value: _languageKey,
                dropdownColor: _themeColor.dropdownColor,
                items: [
                  const DropdownMenuItem<String?>(
                    value: null,
                    child: Text('Default'),
                  ),
                  ...LanguageCatalog.names.entries.map(
                        (entry) => DropdownMenuItem<String?>(
                      value: entry.key,
                      child: Text(entry.value),
                    ),
                  ),
                ],
                onChanged: (String? value) {
                  setState(() {
                    _languageKey = value;
                  });
                },
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildTheme() {
    final l = AppLocalizations.of(context)!;
    return Card(
      margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
      color: _themeColor.cardColor,
      elevation: 0,
      shadowColor: Colors.transparent,
      surfaceTintColor: Colors.transparent,
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            ListTile(
              title: Text(l.theme,style: Theme.of(context).textTheme.bodyMedium),
              contentPadding: const EdgeInsets.symmetric(horizontal: 0),
              trailing: DropdownButton<int>(
                value: _themeNumber,
                dropdownColor: _themeColor.dropdownColor,
                items: [
                  DropdownMenuItem(value: 0, child: Text(l.systemDefault)),
                  DropdownMenuItem(value: 1, child: Text(l.lightTheme)),
                  DropdownMenuItem(value: 2, child: Text(l.darkTheme)),
                ],
                onChanged: (int? value) {
                  if (value == null) {
                    return;
                  }
                  setState(() {
                    _themeNumber = value;
                  });
                },
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildUsage() {
    final l = AppLocalizations.of(context)!;
    return SizedBox(
      width: double.infinity,
      child: Card(
        margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
        color: _themeColor.cardColor,
        elevation: 0,
        shadowColor: Colors.transparent,
        surfaceTintColor: Colors.transparent,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children:[
              Text(l.usage1),
              const SizedBox(height:15),
              Text(l.usage2),
              if (l.usage3 != '') Column(children: [
                const SizedBox(height:15),
                Text(l.usage3),
              ]),
              if (l.usage4 != '') Column(children: [
                const SizedBox(height:15),
                Text(l.usage4),
              ])
            ]
          ),
        ),
      )
    );
  }

  Widget _buildVersion() {
    return SizedBox(
      width: double.infinity,
      child: Card(
        margin: const EdgeInsets.only(left: 4, top: 12, right: 4, bottom: 0),
        color: _themeColor.cardColor,
        elevation: 0,
        shadowColor: Colors.transparent,
        surfaceTintColor: Colors.transparent,
        child: Padding(
          padding: const EdgeInsets.symmetric(vertical: 16),
          child: Center(
            child: Text(
              'version  ${VersionState.versionLoad()}',
              style: const TextStyle(fontSize: 10),
            ),
          ),
        ),
      ),
    );
  }

}

lib/version_state.dart

///
/// @author akira ohmachi
/// @copyright ao-system, Inc.
/// @date 2023-01-27
///
library;

class VersionState {

  static String _version = '';

  //バージョンを記録
  static void versionSave(String str) {
    _version = str;
  }
  //バージョンを返す
  static String versionLoad() {
    return _version;
  }

}

ソースコード source code

下記コードの最終ビルド日： 2025-10-04

pubspec.yaml

lib/ad_banner_widget.dart

lib/ad_manager.dart

lib/audio_play.dart

lib/const_value.dart

lib/empty.dart

lib/language_support.dart

lib/loading_screen.dart

lib/main.dart

lib/preferences.dart

lib/setting.dart

lib/version_state.dart

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