add localization and translation to German (mwageringel#6)

* add localization dependency

* add localization import

* update MaterialApp w/ localization

* add dependency 'intl'

* enable generate flag

Enabled the generate flag for localization.

* add localization config

* add initial translation files

* l10n: update black background

* l10n: convert strings

Added more strings to localization.

* l10n: translated german

Translated all (so far) missing strings into german.

l10n.yaml

@@ -0,0 +1,3 @@
+arb-dir: lib/l10n
+template-arb-file: app_en.arb
+output-localization-file: app_localizations.dart

lib/l10n/app_de.arb

@@ -0,0 +1,12 @@
+{
+    "settings": "Einstellungen",
+    "theme": "Theme",
+    "themeSystem": "System",
+    "themeLight": "Hell",
+    "themeDark": "Dunkel",
+    "darkThemeBlackBackground": "Schwarzer Hintergrund im dunklen Theme",
+    "darkThemeBlackBackgroundSubtitle": "Hauptsächlich für OLED-Bildschirme gedacht",
+    "restart": "Neustart",
+    "restartSubtitle": "Gedrückt halten um Fortschritt zurückzusetzen",
+    "moreInfo": "Mehr Informationen unter "
+}

lib/l10n/app_en.arb

@@ -0,0 +1,12 @@
+{
+    "settings": "Settings",
+    "theme": "Theme",
+    "themeSystem": "system",
+    "themeLight": "light",
+    "themeDark": "dark",
+    "darkThemeBlackBackground": "Black background in dark theme",
+    "darkThemeBlackBackgroundSubtitle": "Mainly intended for OLED screens",
+    "restart": "Restart",
+    "restartSubtitle": "Long press to reset the progress",
+    "moreInfo": "More information at "
+}

lib/main.dart

@@ -4,6 +4,8 @@ import 'dart:math';
 import 'package:flutter/material.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:provider/provider.dart';
 import 'package:path/path.dart';
 import 'package:sqflite/sqflite.dart';
@@ -374,9 +376,9 @@ class SettingsScreen extends StatelessWidget {
     return ListView(
       padding: listPadding,
       children: [
-        const ListTile(
-          leading: Icon(Icons.settings_brightness),
-          title: Text('Theme'),
+        ListTile(
+          leading: const Icon(Icons.settings_brightness),
+          title: Text(AppLocalizations.of(context)!.theme),
         ),
         Consumer2<World, Game>(builder: (context, world, game, child) =>
           Column(
@@ -393,8 +395,8 @@ class SettingsScreen extends StatelessWidget {
                 ),
               )),
               SwitchListTile(
-                title: const Text("Use pure black background in dark theme"),
-                subtitle: const Text("Mainly intended for OLED screens"),
+                title: Text(AppLocalizations.of(context)!.darkThemeBlackBackground),
+                subtitle: Text(AppLocalizations.of(context)!.darkThemeBlackBackgroundSubtitle),
                 value: world.pureBlack,
                 onChanged: (bool value) async {
                   world.switchTheme(pureBlack: value);
@@ -408,8 +410,8 @@ class SettingsScreen extends StatelessWidget {
         Consumer2<World, Game>(builder: (context, world, game, child) =>
           ListTile(
             leading: const Icon(Icons.restore),
-            title: const Text('Restart'),
-            subtitle: const Text('Long press to reset the progress.'),
+            title: Text(AppLocalizations.of(context)!.restart),
+            subtitle: Text(AppLocalizations.of(context)!.restartSubtitle),
             onLongPress: () async {
               await game.resetProgress();
               world.resetWorld();
@@ -424,7 +426,7 @@ class SettingsScreen extends StatelessWidget {
             SelectableText.rich(
               TextSpan(
                 children: <TextSpan>[
-                  TextSpan(style: textStyle, text: 'More info at '),
+                  TextSpan(style: textStyle, text: AppLocalizations.of(context)!.moreInfo),
                   TextSpan(
                       style: textStyle.copyWith(color: theme.colorScheme.primary),
                       text: 'https://mwageringel.github.io/everest/'),  // TODO make hyperlink clickable or copy to clipboard
@@ -509,7 +511,7 @@ class ExamsScreen extends StatelessWidget {
         builder: (context) {
           return Scaffold(
             appBar: AppBar(
-              title: const Text('Settings'),
+              title: Text(AppLocalizations.of(context)!.settings),
             ),
             body: const SettingsScreen(),
           );
@@ -526,7 +528,7 @@ class ExamsScreen extends StatelessWidget {
         IconButton(
           icon: const Icon(Icons.menu),
           onPressed: () => _pushSettings(context),
-          tooltip: 'Settings',
+          tooltip: AppLocalizations.of(context)!.settings,
         ),
       ],
       child: ListView.builder(
@@ -656,6 +658,16 @@ class MyApp extends StatelessWidget {
           visualDensity: FlexColorScheme.comfortablePlatformDensity,
           darkIsTrueBlack: world.pureBlack,
         ),
+        localizationsDelegates: const [
+          AppLocalizations.delegate,
+          GlobalMaterialLocalizations.delegate,
+          GlobalWidgetsLocalizations.delegate,
+          GlobalCupertinoLocalizations.delegate,
+        ],
+        supportedLocales: const [
+          Locale('en', ''), // English, no country code
+          Locale('de', ''), // German, no country code
+        ],
         home: const ExamsScreen(),
       ),
     );

pubspec.yaml

@@ -29,6 +29,9 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
+  flutter_localizations:
+    sdk: flutter
+  intl: ^0.17.0
   sqflite:
   path:
 
@@ -59,6 +62,9 @@ dev_dependencies:
 # The following section is specific to Flutter.
 flutter:
 
+  # Enabled for flutter_localizations, for more information see https://docs.flutter.dev/development/accessibility-and-localization/internationalization
+  generate: true
+
   # 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.