feat: support several language arb files

lib/app.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_localized_locales/flutter_localized_locales.dart';
 import 'package:pdf_signature/l10n/app_localizations.dart';
 import 'package:pdf_signature/ui/features/pdf/widgets/pdf_screen.dart';
 import 'ui/features/preferences/providers.dart';
@@ -55,7 +56,10 @@ class MyApp extends StatelessWidget {
                 themeMode: themeMode,
                 locale: appLocale,
                 supportedLocales: AppLocalizations.supportedLocales,
-                localizationsDelegates: AppLocalizations.localizationsDelegates,
+                localizationsDelegates: [
+                  ...AppLocalizations.localizationsDelegates,
+                  LocaleNamesLocalizationsDelegate(),
+                ],
                 home: const PdfSignatureHomePage(),
               );
             },

lib/data/model/model.dart

@@ -49,9 +49,7 @@ class PdfState {
     signedPage: signedPage ?? this.signedPage,
     placementsByPage: placementsByPage ?? this.placementsByPage,
     selectedPlacementIndex:
-        selectedPlacementIndex == null
+        selectedPlacementIndex ?? this.selectedPlacementIndex,
-            ? this.selectedPlacementIndex
-            : selectedPlacementIndex,
   );
 }
 

lib/l10n/app_de.arb

@@ -0,0 +1,39 @@
+{
+  "appTitle": "PDF-Signatur",
+  "backgroundRemoval": "Hintergrund entfernen",
+  "brightness": "Helligkeit",
+  "clear": "Löschen",
+  "confirm": "Bestätigen",
+  "contrast": "Kontrast",
+  "createNewSignature": "Neue Signatur erstellen",
+  "delete": "Löschen",
+  "downloadStarted": "Download gestartet",
+  "dpi": "DPI:",
+  "drawSignature": "Signatur zeichnen",
+  "errorWithMessage": "Fehler: {message}",
+  "exportingPleaseWait": "Exportiere… Bitte warten",
+  "failedToGeneratePdf": "PDF konnte nicht generiert werden",
+  "failedToSavePdf": "PDF konnte nicht gespeichert werden",
+  "goTo": "Gehe zu:",
+  "invalidOrUnsupportedFile": "Ungültige oder nicht unterstützte Datei",
+  "language": "Sprache",
+  "loadSignatureFromFile": "Signatur aus Datei laden",
+  "lockAspectRatio": "Seitenverhältnis sperren",
+  "longPressOrRightClickTheSignatureToConfirmOrDelete": "Drücken Sie lange oder klicken Sie mit der rechten Maustaste auf die Signatur, um sie zu bestätigen oder zu löschen.",
+  "next": "Weiter",
+  "noPdfLoaded": "Keine PDF-Datei geladen",
+  "nothingToSaveYet": "Noch nichts zu speichern",
+  "openPdf": "PDF öffnen...",
+  "pageInfo": "Seite {current}/{total}",
+  "prev": "Vorherige",
+  "resetToDefaults": "Auf Standardwerte zurücksetzen",
+  "savedWithPath": "Gespeichert: {path}",
+  "saveSignedPdf": "Signiertes PDF speichern",
+  "settings": "Einstellungen",
+  "signature": "Signatur",
+  "theme": "Design",
+  "themeDark": "Dunkel",
+  "themeLight": "Hell",
+  "themeSystem": "System",
+  "undo": "Rückgängig"
+}

lib/l10n/app_en.arb

@@ -43,12 +43,6 @@
   "@invalidOrUnsupportedFile": {},
   "language": "Language",
   "@language": {},
-  "languageChineseTraditional": "Traditional Chinese",
-  "@languageChineseTraditional": {},
-  "languageEnglish": "English",
-  "@languageEnglish": {},
-  "languageSpanish": "Spanish",
-  "@languageSpanish": {},
   "loadSignatureFromFile": "Load Signature from file",
   "@loadSignatureFromFile": {},
   "lockAspectRatio": "Lock aspect ratio",

lib/l10n/app_es.arb

@@ -17,9 +17,6 @@
   "goTo": "Ir a:",
   "invalidOrUnsupportedFile": "Archivo inválido o no compatible",
   "language": "Idioma",
-  "languageChineseTraditional": "Chino tradicional",
-  "languageEnglish": "Inglés",
-  "languageSpanish": "Español",
   "loadSignatureFromFile": "Cargar firma desde archivo",
   "lockAspectRatio": "Bloquear relación de aspecto",
   "longPressOrRightClickTheSignatureToConfirmOrDelete": "Pulse prolongadamente o haga clic derecho en la firma para confirmar o eliminar.",

lib/l10n/app_fr.arb

@@ -0,0 +1,39 @@
+{
+  "appTitle": "Signature PDF",
+  "backgroundRemoval": "Suppression de l'arrière-plan",
+  "brightness": "Luminosité",
+  "clear": "Effacer",
+  "confirm": "Confirmer",
+  "contrast": "Contraste",
+  "createNewSignature": "Créer une nouvelle signature",
+  "delete": "Supprimer",
+  "downloadStarted": "Téléchargement commencé",
+  "dpi": "DPI :",
+  "drawSignature": "Dessiner une signature",
+  "errorWithMessage": "Erreur : {message}",
+  "exportingPleaseWait": "Exportation… Veuillez patienter",
+  "failedToGeneratePdf": "Échec de la génération du PDF",
+  "failedToSavePdf": "Échec de l'enregistrement du PDF",
+  "goTo": "Aller à :",
+  "invalidOrUnsupportedFile": "Fichier invalide ou non pris en charge",
+  "language": "Langue",
+  "loadSignatureFromFile": "Charger une signature depuis un fichier",
+  "lockAspectRatio": "Verrouiller le ratio largeur/hauteur",
+  "longPressOrRightClickTheSignatureToConfirmOrDelete": "Appuyez longuement ou cliquez droit sur la signature pour la confirmer ou la supprimer.",
+  "next": "Suivant",
+  "noPdfLoaded": "Aucun PDF chargé",
+  "nothingToSaveYet": "Rien à enregistrer pour le moment",
+  "openPdf": "Ouvrir un PDF...",
+  "pageInfo": "Page {current}/{total}",
+  "prev": "Précédent",
+  "resetToDefaults": "Rétablir les valeurs par défaut",
+  "savedWithPath": "Enregistré : {path}",
+  "saveSignedPdf": "Enregistrer le PDF signé",
+  "settings": "Paramètres",
+  "signature": "Signature",
+  "theme": "Thème",
+  "themeDark": "Sombre",
+  "themeLight": "Clair",
+  "themeSystem": "Système",
+  "undo": "Annuler"
+}

lib/l10n/app_ja.arb

@@ -0,0 +1,39 @@
+{
+  "appTitle": "PDF署名",
+  "backgroundRemoval": "背景除去",
+  "brightness": "明るさ",
+  "clear": "クリア",
+  "confirm": "確認",
+  "contrast": "コントラスト",
+  "createNewSignature": "新しい署名を作成",
+  "delete": "削除",
+  "downloadStarted": "ダウンロード開始",
+  "dpi": "DPI：",
+  "drawSignature": "署名をかく",
+  "errorWithMessage": "エラー：{message}",
+  "exportingPleaseWait": "エクスポート中…お待ちください",
+  "failedToGeneratePdf": "PDFの生成に失敗しました",
+  "failedToSavePdf": "PDFの保存に失敗しました",
+  "goTo": "移動：",
+  "invalidOrUnsupportedFile": "無効なファイルまたはサポートされていないファイル",
+  "language": "言語",
+  "loadSignatureFromFile": "ファイルから署名を読み込む",
+  "lockAspectRatio": "アスペクト比をロック",
+  "longPressOrRightClickTheSignatureToConfirmOrDelete": "署名を長押しまたは右クリックして、確認または削除します。",
+  "next": "次へ",
+  "noPdfLoaded": "PDFが読み込まれていません",
+  "nothingToSaveYet": "まだ保存するものがありません",
+  "openPdf": "PDFを開く…",
+  "pageInfo": "ページ {current}/{total}",
+  "prev": "前へ",
+  "resetToDefaults": "デフォルトに戻す",
+  "savedWithPath": "保存しました：{path}",
+  "saveSignedPdf": "署名済みPDFを保存",
+  "settings": "設定",
+  "signature": "署名",
+  "theme": "テーマ",
+  "themeDark": "ダーク",
+  "themeLight": "ライト",
+  "themeSystem": "システム",
+  "undo": "元に戻す"
+}

lib/l10n/app_ko.arb

@@ -0,0 +1,39 @@
+{
+  "appTitle": "PDF 서명",
+  "backgroundRemoval": "배경 제거",
+  "brightness": "밝기",
+  "clear": "지우기",
+  "confirm": "확인",
+  "contrast": "대비",
+  "createNewSignature": "새 서명 만들기",
+  "delete": "삭제",
+  "downloadStarted": "다운로드 시작됨",
+  "dpi": "DPI:",
+  "drawSignature": "서명 그리기",
+  "errorWithMessage": "오류: {message}",
+  "exportingPleaseWait": "내보내는 중... 잠시 기다려주세요",
+  "failedToGeneratePdf": "PDF 생성 실패",
+  "failedToSavePdf": "PDF 저장 실패",
+  "goTo": "이동:",
+  "invalidOrUnsupportedFile": "잘못된 파일이거나 지원되지 않는 파일입니다.",
+  "language": "언어",
+  "loadSignatureFromFile": "파일에서 서명 불러오기",
+  "lockAspectRatio": "종횡비 고정",
+  "longPressOrRightClickTheSignatureToConfirmOrDelete": "서명을 길게 누르거나 마우스 오른쪽 버튼을 클릭하여 확인하거나 삭제합니다.",
+  "next": "다음",
+  "noPdfLoaded": "로드된 PDF 없음",
+  "nothingToSaveYet": "아직 저장할 내용이 없습니다.",
+  "openPdf": "PDF 열기...",
+  "pageInfo": "{current}/{total} 페이지",
+  "prev": "이전",
+  "resetToDefaults": "기본값으로 재설정",
+  "savedWithPath": "{path}에 저장됨",
+  "saveSignedPdf": "서명된 PDF 저장",
+  "settings": "설정",
+  "signature": "서명",
+  "theme": "테마",
+  "themeDark": "다크",
+  "themeLight": "라이트",
+  "themeSystem": "시스템",
+  "undo": "실행 취소"
+}

lib/l10n/app_uk.arb

@@ -0,0 +1,39 @@
+{
+  "appTitle": "Підпис PDF",
+  "backgroundRemoval": "Видалення фону",
+  "brightness": "Яскравість",
+  "clear": "Очистити",
+  "confirm": "Підтвердити",
+  "contrast": "Контрастність",
+  "createNewSignature": "Створити новий підпис",
+  "delete": "Видалити",
+  "downloadStarted": "Завантаження розпочато",
+  "dpi": "DPI:",
+  "drawSignature": "Намалювати підпис",
+  "errorWithMessage": "Помилка: {message}",
+  "exportingPleaseWait": "Експортування... Зачекайте",
+  "failedToGeneratePdf": "Не вдалося створити PDF",
+  "failedToSavePdf": "Не вдалося зберегти PDF",
+  "goTo": "Перейти до:",
+  "invalidOrUnsupportedFile": "Недійсний або непідтримуваний файл",
+  "language": "Мова",
+  "loadSignatureFromFile": "Завантажити підпис з файлу",
+  "lockAspectRatio": "Зафіксувати співвідношення сторін",
+  "longPressOrRightClickTheSignatureToConfirmOrDelete": "Довго натисніть або клацніть правою кнопкою миші на підпис, щоб підтвердити або видалити.",
+  "next": "Далі",
+  "noPdfLoaded": "PDF не завантажено",
+  "nothingToSaveYet": "Ще нічого не потрібно зберігати",
+  "openPdf": "Відкрити PDF...",
+  "pageInfo": "Сторінка {current}/{total}",
+  "prev": "Попередня",
+  "resetToDefaults": "Скинути до значень за замовчуванням",
+  "savedWithPath": "Збережено: {path}",
+  "saveSignedPdf": "Зберегти підписаний PDF",
+  "settings": "Налаштування",
+  "signature": "Підпис",
+  "theme": "Тема",
+  "themeDark": "Темна",
+  "themeLight": "Світла",
+  "themeSystem": "Системна",
+  "undo": "Відмінити"
+}

lib/l10n/app_zh.arb

@@ -18,9 +18,6 @@
   "goTo": "前往：",
   "invalidOrUnsupportedFile": "無效或不支援的檔案",
   "language": "語言",
-  "languageChineseTraditional": "繁體中文",
-  "languageEnglish": "英文",
-  "languageSpanish": "西班牙文",
   "loadSignatureFromFile": "從檔案載入簽名",
   "lockAspectRatio": "鎖定長寬比",
   "longPressOrRightClickTheSignatureToConfirmOrDelete": "長按或右鍵點擊簽名以確認或刪除。",

lib/l10n/app_zh_CN.arb

@@ -0,0 +1,39 @@
+{
+  "appTitle": "PDF 签名",
+  "backgroundRemoval": "背景移除",
+  "brightness": "亮度",
+  "clear": "清除",
+  "confirm": "确认",
+  "contrast": "对比度",
+  "createNewSignature": "创建新的签名",
+  "delete": "删除",
+  "downloadStarted": "下载已开始",
+  "dpi": "DPI：",
+  "drawSignature": "绘制签名",
+  "errorWithMessage": "错误：{message}",
+  "exportingPleaseWait": "正在导出... 请稍候",
+  "failedToGeneratePdf": "PDF 生成失败",
+  "failedToSavePdf": "PDF 保存失败",
+  "goTo": "跳转到：",
+  "invalidOrUnsupportedFile": "无效或不支持的文件",
+  "language": "语言",
+  "loadSignatureFromFile": "从文件加载签名",
+  "lockAspectRatio": "锁定纵横比",
+  "longPressOrRightClickTheSignatureToConfirmOrDelete": "长按或右键单击签名以确认或删除。",
+  "next": "下一步",
+  "noPdfLoaded": "未加载 PDF",
+  "nothingToSaveYet": "尚无内容保存",
+  "openPdf": "打开 PDF...",
+  "pageInfo": "第 {current} 页 / 共 {total} 页",
+  "prev": "上一页",
+  "resetToDefaults": "恢复默认值",
+  "savedWithPath": "已保存：{path}",
+  "saveSignedPdf": "保存已签名的 PDF",
+  "settings": "设置",
+  "signature": "签名",
+  "theme": "主题",
+  "themeDark": "深色",
+  "themeLight": "浅色",
+  "themeSystem": "系统",
+  "undo": "撤销"
+}

lib/l10n/app_zh_TW.arb

@@ -18,9 +18,6 @@
   "goTo": "前往：",
   "invalidOrUnsupportedFile": "無效或不支援的檔案",
   "language": "語言",
-  "languageChineseTraditional": "繁體中文",
-  "languageEnglish": "英文",
-  "languageSpanish": "西班牙文",
   "loadSignatureFromFile": "從檔案載入簽名",
   "lockAspectRatio": "鎖定長寬比",
   "longPressOrRightClickTheSignatureToConfirmOrDelete": "長按或右鍵點擊簽名以確認或刪除。",

lib/ui/features/preferences/providers.dart

@@ -1,32 +1,64 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:shared_preferences/shared_preferences.dart';
+import 'package:pdf_signature/l10n/app_localizations.dart';
+import 'package:flutter_localized_locales/flutter_localized_locales.dart';
 
-// Simple supported locales
+// Helpers to work with BCP-47 language tags
-const supportedLocales = <Locale>[
+String toLanguageTag(Locale loc) {
-  Locale('en'),
+  final lang = loc.languageCode.toLowerCase();
-  Locale('zh', 'TW'),
+  final region = loc.countryCode;
-  Locale('es'),
+  if (region == null || region.isEmpty) return lang;
-];
+  return '$lang-${region.toUpperCase()}';
+}
+
+Locale _parseLanguageTag(String tag) {
+  final cleaned = tag.replaceAll('_', '-');
+  final parts = cleaned.split('-');
+  if (parts.length >= 2 && parts[1].isNotEmpty) {
+    return Locale(parts[0].toLowerCase(), parts[1].toUpperCase());
+  }
+  return Locale(parts[0].toLowerCase());
+}
+
+Set<String> _supportedTags() {
+  return AppLocalizations.supportedLocales.map((l) => toLanguageTag(l)).toSet();
+}
 
 // Keys
 const _kTheme = 'theme'; // 'light'|'dark'|'system'
-const _kLanguage = 'language'; // 'en'|'zh-TW'|'es'
+const _kLanguage = 'language'; // BCP-47 tag like 'en', 'zh-TW', 'es'
 
 String _normalizeLanguageTag(String tag) {
-  final parts = tag.split('-');
+  final tags = _supportedTags();
-  if (parts.isEmpty) return 'en';
+  if (tag.isEmpty) return tags.contains('en') ? 'en' : tags.first;
-  final primary = parts[0].toLowerCase();
+  // Replace underscore with hyphen and canonicalize case
-  if (primary == 'en') return 'en';
+  final normalized = () {
-  if (primary == 'es') return 'es';
+    final t = tag.replaceAll('_', '-');
-  if (primary == 'zh') {
+    final parts = t.split('-');
-    final region = parts.length > 1 ? parts[1].toUpperCase() : '';
+    final lang = parts[0].toLowerCase();
-    if (region == 'TW') return 'zh-TW';
+    if (parts.length >= 2 && parts[1].isNotEmpty) {
-    // other zh regions not supported; fall back to English
+      return '$lang-${parts[1].toUpperCase()}';
-    return 'en';
     }
-  // Fallback default
+    return lang;
-  return 'en';
+  }();
+
+  // Exact match
+  if (tags.contains(normalized)) return normalized;
+
+  // Try fallback to language-only if available
+  final langOnly = normalized.split('-')[0];
+  if (tags.contains(langOnly)) return langOnly;
+
+  // Try to pick first tag with same language
+  final candidate = tags.firstWhere(
+    (t) => t.split('-')[0] == langOnly,
+    orElse: () => '',
+  );
+  if (candidate.isNotEmpty) return candidate;
+
+  // Final fallback to English or first supported
+  return tags.contains('en') ? 'en' : tags.first;
 }
 
 class PreferencesState {
@@ -49,7 +81,8 @@ class PreferencesNotifier extends StateNotifier<PreferencesState> {
           theme: prefs.getString(_kTheme) ?? 'system',
           language: _normalizeLanguageTag(
             prefs.getString(_kLanguage) ??
-                WidgetsBinding.instance.platformDispatcher.locale.toLanguageTag(),
+                WidgetsBinding.instance.platformDispatcher.locale
+                    .toLanguageTag(),
           ),
         ),
       ) {
@@ -84,7 +117,8 @@ class PreferencesNotifier extends StateNotifier<PreferencesState> {
   }
 
   Future<void> resetToDefaults() async {
-  final device = WidgetsBinding.instance.platformDispatcher.locale.toLanguageTag();
+    final device =
+        WidgetsBinding.instance.platformDispatcher.locale.toLanguageTag();
     final normalized = _normalizeLanguageTag(device);
     state = PreferencesState(theme: 'system', language: normalized);
     await prefs.setString(_kTheme, 'system');
@@ -125,19 +159,28 @@ final themeModeProvider = Provider<ThemeMode>((ref) {
   }
 });
 
-Locale _parseLanguageTag(String tag) {
-  // 'zh-TW' -> ('zh','TW')
-  final parts = tag.split('-');
-  if (parts.length == 2) return Locale(parts[0], parts[1]);
-  return Locale(parts[0]);
-}
-
 final localeProvider = Provider<Locale?>((ref) {
   final prefs = ref.watch(preferencesProvider);
+  final supported = _supportedTags();
   // Return explicit Locale for supported ones; if not supported, null to follow device
-  final supported = {'en', 'zh-TW', 'es'};
   if (supported.contains(prefs.language)) {
     return _parseLanguageTag(prefs.language);
   }
   return null;
 });
+
+/// Provides a map of BCP-47 tag -> autonym (self name), independent of UI locale.
+final languageAutonymsProvider = FutureProvider<Map<String, String>>((
+  ref,
+) async {
+  final tags = _supportedTags().toList()..sort();
+  final delegate = LocaleNamesLocalizationsDelegate();
+  final Map<String, String> result = {};
+  for (final tag in tags) {
+    final locale = _parseLanguageTag(tag);
+    final names = await delegate.load(locale);
+    final name = names.nameOf(tag) ?? tag;
+    result[tag] = name;
+  }
+  return result;
+});

lib/ui/features/preferences/widgets/settings_screen.dart

@@ -39,17 +39,26 @@ class SettingsScreen extends ConsumerWidget {
               style: const TextStyle(fontWeight: FontWeight.bold),
             ),
             const SizedBox(height: 8),
-            DropdownButton<String>(
+            ref
+                .watch(languageAutonymsProvider)
+                .when(
+                  loading:
+                      () => const SizedBox(
+                        height: 48,
+                        child: Center(child: CircularProgressIndicator()),
+                      ),
+                  error:
+                      (_, __) => DropdownButton<String>(
                         key: const Key('ddl_language'),
                         value: prefs.language,
-              items: [
+                        items:
-                DropdownMenuItem(value: 'en', child: Text(l.languageEnglish)),
+                            AppLocalizations.supportedLocales.map((loc) {
-                DropdownMenuItem(
+                              final tag = toLanguageTag(loc);
-                  value: 'zh-TW',
+                              return DropdownMenuItem<String>(
-                  child: Text(l.languageChineseTraditional),
+                                value: tag,
-                ),
+                                child: Text(tag),
-                DropdownMenuItem(value: 'es', child: Text(l.languageSpanish)),
+                              );
-              ],
+                            }).toList(),
                         onChanged:
                             (v) =>
                                 v == null
@@ -58,6 +67,34 @@ class SettingsScreen extends ConsumerWidget {
                                         .read(preferencesProvider.notifier)
                                         .setLanguage(v),
                       ),
+                  data: (names) {
+                    final items =
+                        AppLocalizations.supportedLocales
+                            .map((loc) => toLanguageTag(loc))
+                            .toList()
+                          ..sort();
+                    return DropdownButton<String>(
+                      key: const Key('ddl_language'),
+                      value: prefs.language,
+                      items:
+                          items
+                              .map(
+                                (tag) => DropdownMenuItem<String>(
+                                  value: tag,
+                                  child: Text(names[tag] ?? tag),
+                                ),
+                              )
+                              .toList(),
+                      onChanged:
+                          (v) =>
+                              v == null
+                                  ? null
+                                  : ref
+                                      .read(preferencesProvider.notifier)
+                                      .setLanguage(v),
+                    );
+                  },
+                ),
             const Spacer(),
             Align(
               alignment: Alignment.bottomRight,

pubspec.yaml

@@ -49,6 +49,7 @@ dependencies:
   flutter_localizations:
     sdk: flutter
   intl: any
+  flutter_localized_locales: ^2.0.5
 
 dev_dependencies:
   flutter_test: