Switch dark mode in runtime

lib/event/event.dart

@@ -61,3 +61,5 @@ class FileRemovedEvent {
   final Account account;
   final File file;
 }
+
+class ThemeChangedEvent {}

lib/pref.dart

@@ -56,6 +56,10 @@ class Pref {
 
   Future<bool> setLastVersion(int value) => _pref.setInt("lastVersion", value);
 
+  bool isDarkTheme([bool def = false]) => _pref.getBool("isDarkTheme") ?? def;
+
+  Future<bool> setDarkTheme(bool value) => _pref.setBool("isDarkTheme", value);
+
   Pref._();
 
   static final _inst = Pref._();

lib/theme.dart

@@ -105,6 +105,14 @@ class AppTheme extends StatelessWidget {
         : Colors.white60;
   }
 
+  static Color getAppBarDarkModeSwitchColor(BuildContext context) {
+    return Colors.black87;
+  }
+
+  static Color getAppBarDarkModeSwitchTrackColor(BuildContext context) {
+    return Colors.white.withOpacity(.5);
+  }
+
   static const primarySwatchLight = Colors.blue;
   static const primarySwatchDark = Colors.cyan;
 

lib/widget/home_app_bar.dart

@@ -1,7 +1,11 @@
+import 'package:event_bus/event_bus.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+import 'package:kiwi/kiwi.dart';
 import 'package:nc_photos/account.dart';
+import 'package:nc_photos/event/event.dart';
+import 'package:nc_photos/pref.dart';
 import 'package:nc_photos/theme.dart';
 import 'package:nc_photos/widget/account_picker_dialog.dart';
 import 'package:nc_photos/widget/settings.dart';
@@ -63,6 +67,19 @@ class HomeSliverAppBar extends StatelessWidget {
       automaticallyImplyLeading: false,
       actions: (actions ?? []) +
           [
+            Switch(
+              value: Theme.of(context).brightness == Brightness.dark,
+              onChanged: _onDarkModeChanged,
+              activeColor: AppTheme.getAppBarDarkModeSwitchColor(context),
+              inactiveThumbColor:
+                  AppTheme.getAppBarDarkModeSwitchColor(context),
+              activeTrackColor:
+                  AppTheme.getAppBarDarkModeSwitchTrackColor(context),
+              activeThumbImage:
+                  const AssetImage("assets/ic_dark_mode_switch_24dp.png"),
+              inactiveThumbImage:
+                  const AssetImage("assets/ic_dark_mode_switch_24dp.png"),
+            ),
             PopupMenuButton(
               tooltip: MaterialLocalizations.of(context).moreButtonTooltip,
               itemBuilder: (context) =>
@@ -89,6 +106,12 @@ class HomeSliverAppBar extends StatelessWidget {
     );
   }
 
+  void _onDarkModeChanged(bool value) {
+    Pref.inst().setDarkTheme(value).then((_) {
+      KiwiContainer().resolve<EventBus>().fire(ThemeChangedEvent());
+    });
+  }
+
   final Account account;
 
   /// Screen specific action buttons

lib/widget/my_app.dart

@@ -2,6 +2,8 @@ import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:logging/logging.dart';
+import 'package:nc_photos/event/event.dart';
+import 'package:nc_photos/pref.dart';
 import 'package:nc_photos/snack_bar_manager.dart';
 import 'package:nc_photos/theme.dart';
 import 'package:nc_photos/widget/album_viewer.dart';
@@ -14,9 +16,18 @@ import 'package:nc_photos/widget/sign_in.dart';
 import 'package:nc_photos/widget/splash.dart';
 import 'package:nc_photos/widget/viewer.dart';
 
-class MyApp extends StatelessWidget implements SnackBarHandler {
-  MyApp() {
+class MyApp extends StatefulWidget {
+  @override
+  createState() => _MyAppState();
+}
+
+class _MyAppState extends State<MyApp> implements SnackBarHandler {
+  @override
+  void initState() {
+    super.initState();
     SnackBarManager().registerHandler(this);
+    _themeChangedListener =
+        AppEventListener<ThemeChangedEvent>(_onThemeChangedEvent)..begin();
   }
 
   @override
@@ -25,6 +36,7 @@ class MyApp extends StatelessWidget implements SnackBarHandler {
       onGenerateTitle: (context) => AppLocalizations.of(context).appTitle,
       theme: _getLightTheme(),
       darkTheme: _getDarkTheme(),
+      themeMode: Pref.inst().isDarkTheme() ? ThemeMode.dark : ThemeMode.light,
       initialRoute: Splash.routeName,
       onGenerateRoute: _onGenerateRoute,
       scaffoldMessengerKey: _scaffoldMessengerKey,
@@ -34,6 +46,13 @@ class MyApp extends StatelessWidget implements SnackBarHandler {
     );
   }
 
+  @override
+  void dispose() {
+    super.dispose();
+    SnackBarManager().unregisterHandler(this);
+    _themeChangedListener.end();
+  }
+
   @override
   showSnackBar(SnackBar snackBar) =>
       _scaffoldMessengerKey.currentState?.showSnackBar(snackBar);
@@ -67,6 +86,10 @@ class MyApp extends StatelessWidget implements SnackBarHandler {
     return route;
   }
 
+  void _onThemeChangedEvent(ThemeChangedEvent ev) {
+    setState(() {});
+  }
+
   Route<dynamic> _handleBasicRoute(RouteSettings settings) {
     for (final e in _getRouter().entries) {
       if (e.key == settings.name) {
@@ -165,5 +188,7 @@ class MyApp extends StatelessWidget implements SnackBarHandler {
 
   final _scaffoldMessengerKey = GlobalKey<ScaffoldMessengerState>();
 
-  static final _log = Logger("widget.my_app.MyApp");
+  AppEventListener<ThemeChangedEvent> _themeChangedListener;
+
+  static final _log = Logger("widget.my_app.MyAppState");
 }