Replace isDarkThemeEnabled with Theme.of(context).isDarkTheme

app/lib/account/register_account_section.dart

@@ -67,7 +67,7 @@ class RegisterAccountSection extends StatelessWidget {
           Text(
             "Melde dich jetzt an und übertrage deine Daten! Die Anmeldung ist aus datenschutzrechtlichen Gründen erst ab 16 Jahren erlaubt.",
             style: TextStyle(
-                color: isDarkThemeEnabled(context)
+                color: Theme.of(context).isDarkTheme
                     ? Colors.grey
                     : Colors.grey[600],
                 fontSize: 10),
@@ -218,7 +218,7 @@ class _SignUpButton extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final color =
-        isDarkThemeEnabled(context) ? Colors.grey[400] : Colors.grey[800];
+        Theme.of(context).isDarkTheme ? Colors.grey[400] : Colors.grey[800];
     return InkWell(
       borderRadius: _borderRadius,
       onTap: onTap,

app/lib/account/use_account_on_multiple_devices_instruction.dart

@@ -23,7 +23,7 @@ class UseAccountOnMultipleDevicesInstructions extends StatelessWidget {
       body: DefaultTextStyle(
         textAlign: TextAlign.center,
         style: TextStyle(
-          color: isDarkThemeEnabled(context) ? Colors.white : Colors.black,
+          color: Theme.of(context).isDarkTheme ? Colors.white : Colors.black,
           fontFamily: rubik,
         ),
         child: SingleChildScrollView(

app/lib/activation_code/activation_code_page.dart

@@ -60,7 +60,7 @@ class _EnterActivationCodeAppBar extends StatelessWidget
       ),
       centerTitle: true,
       backgroundColor:
-          isDarkThemeEnabled(context) ? null : Theme.of(context).primaryColor,
+          Theme.of(context).isDarkTheme ? null : Theme.of(context).primaryColor,
       iconTheme: const IconThemeData(color: Colors.white),
       actions: const [],
       bottom: const EnterActivationCodeTextField(),

app/lib/auth/email_and_password_link_page.dart

@@ -36,7 +36,7 @@ Future<void> handleEmailAndPasswordLinkSubmit(BuildContext context) async {
 }
 
 TextStyle _hintTextStyle(BuildContext context) => TextStyle(
-    color: isDarkThemeEnabled(context)
+    color: Theme.of(context).isDarkTheme
         ? Colors.grey
         : Colors.grey[600]!.withOpacity(0.75),
     fontSize: 11.5);
@@ -168,7 +168,7 @@ class BackIcon extends StatelessWidget {
       left: 5,
       child: SafeArea(
         child: IconButton(
-          color: isDarkThemeEnabled(context)
+          color: Theme.of(context).isDarkTheme
               ? Colors.grey
               : darkBlueColor.withOpacity(0.4),
           icon: Icon(themeIconData(Icons.arrow_back,

app/lib/auth/login_page.dart

@@ -495,7 +495,8 @@ class _ResetPasswordButton extends StatelessWidget {
           child: Text(
             'Passwort zurücksetzen',
             style: TextStyle(
-              color: isDarkThemeEnabled(context) ? Colors.grey : Colors.black54,
+              color:
+                  Theme.of(context).isDarkTheme ? Colors.grey : Colors.black54,
             ),
           ),
         );
@@ -534,7 +535,7 @@ class _LoginWithQrCodeButton extends StatelessWidget {
         "assets/icons/qr-code.svg",
         width: 24,
         height: 24,
-        color: isDarkThemeEnabled(context) ? Colors.white : Colors.black,
+        color: Theme.of(context).isDarkTheme ? Colors.white : Colors.black,
       ),
       text: "Über einen Qr-Code einloggen",
       onTap: () => Navigator.pushNamed(context, SignInWithQrCodePage.tag),
@@ -557,7 +558,7 @@ class _LoginWithAppleButton extends StatelessWidget {
         "assets/logo/apple-logo.svg",
         width: 24,
         height: 24,
-        color: isDarkThemeEnabled(context) ? Colors.white : Colors.black,
+        color: Theme.of(context).isDarkTheme ? Colors.white : Colors.black,
       ),
       onTap: onLogin,
       text: 'Über Apple anmelden',
@@ -601,7 +602,7 @@ class _SignWithOAuthButton extends StatelessWidget {
                     child: Text(
                       text.toUpperCase(),
                       style: TextStyle(
-                        color: isDarkThemeEnabled(context)
+                        color: Theme.of(context).isDarkTheme
                             ? Colors.white
                             : Colors.grey[800],
                         fontWeight: FontWeight.w500,

app/lib/blackboard/blackboard_card.dart

@@ -202,7 +202,8 @@ class _TipIcon extends StatelessWidget {
       child: Tooltip(
         message: tooltip,
         child: Icon(icon,
-            color: isDarkThemeEnabled(context) ? Colors.grey : Colors.grey[700],
+            color:
+                Theme.of(context).isDarkTheme ? Colors.grey : Colors.grey[700],
             size: 20),
       ),
     );

app/lib/blackboard/blackboard_dialog.dart

@@ -122,7 +122,7 @@ class __BlackboardDialogState extends State<_BlackboardDialog> {
           ? warnUserAboutLeavingForm(context)
           : Future.value(true),
       child: Scaffold(
-        backgroundColor: isDarkThemeEnabled(context) ? null : Colors.white,
+        backgroundColor: Theme.of(context).isDarkTheme ? null : Colors.white,
         body: Column(
           children: <Widget>[
             _AppBar(
@@ -264,7 +264,7 @@ class _AppBar extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return Material(
-      color: isDarkThemeEnabled(context)
+      color: Theme.of(context).isDarkTheme
           ? Theme.of(context).appBarTheme.backgroundColor
           : Theme.of(context).primaryColor,
       elevation: 1,

app/lib/blackboard/details/blackboard_details.dart

@@ -285,10 +285,8 @@ class _Title extends StatelessWidget {
       padding: const EdgeInsets.only(top: 8),
       child: SelectableText(
         title!,
-        style: Theme.of(context)
-            .textTheme
-            .headlineMedium!
-            .copyWith(color: isDarkThemeEnabled(context) ? null : Colors.black),
+        style: Theme.of(context).textTheme.headlineMedium!.copyWith(
+            color: Theme.of(context).isDarkTheme ? null : Colors.black),
       ),
     );
   }
@@ -394,8 +392,9 @@ class __UserReadTileState extends State<_UserReadTile> {
       child: Container(
         decoration: BoxDecoration(
           shape: BoxShape.circle,
-          color:
-              isDarkThemeEnabled(context) ? Colors.grey[400] : Colors.grey[300],
+          color: Theme.of(context).isDarkTheme
+              ? Colors.grey[400]
+              : Colors.grey[300],
         ),
         width: 30,
         height: 30,
@@ -439,7 +438,7 @@ class _Text extends StatelessWidget {
         theme.copyWith(
           textTheme: theme.textTheme.copyWith(
               bodyMedium: flowingText.copyWith(
-                  color: isDarkThemeEnabled(context)
+                  color: Theme.of(context).isDarkTheme
                       ? Colors.white
                       : Colors.black)),
         ),
@@ -449,7 +448,7 @@ class _Text extends StatelessWidget {
       //   // immer weiß ist. Ticket: https://github.com/flutter/flutter_markdown/issues/198
 
       //   p: flowingText.copyWith(
-      //       color: isDarkThemeEnabled(context) ? Colors.white : Colors.black),
+      //       color: Theme.of(context).isDarkTheme ? Colors.white : Colors.black),
       //   a: linkStyle(context, 15),
       // ),
       onTapLink: (url, _, __) => launchURL(url, context: context),

app/lib/calendrical_events/page/calendrical_events_page.dart

@@ -140,7 +140,7 @@ class _EventListFABSheet extends StatelessWidget {
             const SizedBox(height: 20),
             Text("Neu erstellen",
                 style: TextStyle(
-                    color: isDarkThemeEnabled(context)
+                    color: Theme.of(context).isDarkTheme
                         ? Colors.grey[100]
                         : Colors.grey[800],
                     fontSize: 18)),

app/lib/dashboard/dashboard_page.dart

@@ -90,7 +90,7 @@ class _DashboardPageState extends State<DashboardPage> {
       appBarConfiguration: SliverAppBarConfiguration(
         title: const _AppBarTitle(),
         backgroundColor:
-            isDarkThemeEnabled(context) ? ElevationColors.dp8 : blueColor,
+            Theme.of(context).isDarkTheme ? ElevationColors.dp8 : blueColor,
         expandedHeight: 210,
         elevation: 1,
         pinned: true,

app/lib/dashboard/sections/dashboard_tip.dart

@@ -39,7 +39,7 @@ class _DashboardTipCard extends StatelessWidget {
         child: AnnouncementCard(
           key: ValueKey(dashboardTip),
           padding: const EdgeInsets.all(0),
-          color: isDarkThemeEnabled(context)
+          color: Theme.of(context).isDarkTheme
               ? Colors.deepOrange[700]!
               : Colors.amberAccent,
           title: dashboardTip.title,

app/lib/dashboard/timetable/lesson_card.dart

@@ -9,7 +9,7 @@
 part of '../dashboard_page.dart';
 
 Color _getLessonCardTextColor(BuildContext context) =>
-    isDarkThemeEnabled(context) ? Colors.lightBlue : darkBlueColor;
+    Theme.of(context).isDarkTheme ? Colors.lightBlue : darkBlueColor;
 
 class _LessonCard extends StatelessWidget {
   const _LessonCard(this.view, {Key? key}) : super(key: key);
@@ -54,7 +54,7 @@ class _LessonCard extends StatelessWidget {
                     CircleAvatar(
                       radius: 17.5,
                       backgroundColor: isNow
-                          ? isDarkThemeEnabled(context)
+                          ? Theme.of(context).isDarkTheme
                               ? Theme.of(context).cardColor
                               : Colors.white
                           : color.withOpacity(0.2),

app/lib/dashboard/timetable/lesson_row.dart

@@ -107,7 +107,7 @@ class _EmptyStateMsg extends StatelessWidget {
             text,
             style: TextStyle(
                 fontSize: 18,
-                color: isDarkThemeEnabled(context)
+                color: Theme.of(context).isDarkTheme
                     ? Colors.lightBlue
                     : darkBlueColor),
             textAlign: TextAlign.center,

app/lib/dashboard/widgets/blackboard_card_dashboard.dart

@@ -131,7 +131,7 @@ class _Title extends StatelessWidget {
     return Text(
       title,
       style: TextStyle(
-          color: isDarkThemeEnabled(context)
+          color: Theme.of(context).isDarkTheme
               ? Colors.lightBlue[100]
               : darkBlueColor,
           fontWeight: FontWeight.w500,

app/lib/dashboard/widgets/dashboard_fab.dart

@@ -84,7 +84,7 @@ class _DashboardFabSheet extends StatelessWidget {
             const SizedBox(height: 20),
             Text("Neu erstellen",
                 style: TextStyle(
-                    color: isDarkThemeEnabled(context)
+                    color: Theme.of(context).isDarkTheme
                         ? Colors.grey[100]
                         : Colors.grey[800],
                     fontSize: 18)),

app/lib/dashboard/widgets/section.dart

@@ -28,7 +28,7 @@ class _Section extends StatelessWidget {
             padding: const EdgeInsets.fromLTRB(22, 18, 12, 6),
             child: DefaultTextStyle(
               style: TextStyle(
-                color: isDarkThemeEnabled(context)
+                color: Theme.of(context).isDarkTheme
                     ? Colors.lightBlue
                     : darkBlueColor,
                 fontSize: 18,

app/lib/feedback/feedback_box_page.dart

@@ -111,15 +111,15 @@ class _AnonymousCheckbox extends StatelessWidget {
                 child: Row(
                   children: <Widget>[
                     Icon(Icons.security,
-                        color: isDarkThemeEnabled(context)
+                        color: Theme.of(context).isDarkTheme
                             ? Colors.grey
                             : Colors.grey[600]),
                     const SizedBox(width: 16),
                     Flexible(
                       child: Text(
                         "Ich möchte mein Feedback anonym abschicken",
                         style: TextStyle(
-                            color: isDarkThemeEnabled(context)
+                            color: Theme.of(context).isDarkTheme
                                 ? Colors.grey[400]
                                 : Colors.grey[600],
                             fontSize: 16),

app/lib/filesharing/widgets/file_sharing_page_fab.dart

@@ -186,7 +186,7 @@ class __FABModalBottomSheetContentState
             const SizedBox(height: 20),
             Text("Neu erstellen",
                 style: TextStyle(
-                    color: isDarkThemeEnabled(context)
+                    color: Theme.of(context).isDarkTheme
                         ? Colors.grey[100]
                         : Colors.grey[800],
                     fontSize: 18)),

app/lib/filesharing/widgets/filesharing_headline.dart

@@ -21,7 +21,7 @@ class FileSharingHeadline extends StatelessWidget {
       child: Text(
         title!,
         style: TextStyle(
-            color: isDarkThemeEnabled(context)
+            color: Theme.of(context).isDarkTheme
                 ? Colors.grey[400]
                 : Colors.grey[700],
             fontWeight: FontWeight.w600),

app/lib/filesharing/widgets/sheet.dart

@@ -107,8 +107,9 @@ class FileSheet extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final TextStyle greyTextStyle = TextStyle(
-        color:
-            isDarkThemeEnabled(context) ? Colors.grey[400] : Colors.grey[600]);
+        color: Theme.of(context).isDarkTheme
+            ? Colors.grey[400]
+            : Colors.grey[600]);
     final api = BlocProvider.of<SharezoneContext>(context).api;
     return SafeArea(
       left: true,

app/lib/groups/group_join/group_join_page.dart

@@ -61,7 +61,7 @@ class GroupJoinAppBar extends StatelessWidget implements PreferredSizeWidget {
       automaticallyImplyLeading: withBackIcon,
       centerTitle: true,
       backgroundColor:
-          isDarkThemeEnabled(context) ? null : Theme.of(context).primaryColor,
+          Theme.of(context).isDarkTheme ? null : Theme.of(context).primaryColor,
       iconTheme: const IconThemeData(color: Colors.white),
       actions: const [_SupportIcon()],
       bottom: const GroupJoinTextField(),

app/lib/groups/src/pages/course/course_card.dart

@@ -194,7 +194,7 @@ class CourseCardRedesign extends StatelessWidget {
                     maxLines: 2,
                     overflow: TextOverflow.ellipsis,
                     style: TextStyle(
-                      color: isDarkThemeEnabled(context)
+                      color: Theme.of(context).isDarkTheme
                           ? Colors.lightBlue[100]
                           : darkBlueColor,
                       fontSize: 18,

app/lib/groups/src/pages/course/course_edit/course_edit_page.dart

@@ -113,7 +113,7 @@ class _CourseEditPage extends StatelessWidget {
     final courseNameNode = FocusNode();
     return Scaffold(
       appBar: AppBar(title: const Text("Kurs bearbeiten")),
-      backgroundColor: isDarkThemeEnabled(context) ? null : Colors.white,
+      backgroundColor: Theme.of(context).isDarkTheme ? null : Colors.white,
       body: SingleChildScrollView(
         padding: const EdgeInsets.all(8)
             .add(const EdgeInsets.symmetric(horizontal: 4)),

app/lib/groups/src/pages/course/create/course_template_page.dart

@@ -31,7 +31,7 @@ class CourseTemplatePage extends StatelessWidget {
         centerTitle: true,
         actions: const [CourseTemplatePageFinishButton()],
       ),
-      backgroundColor: isDarkThemeEnabled(context) ? null : Colors.white,
+      backgroundColor: Theme.of(context).isDarkTheme ? null : Colors.white,
       body: const SingleChildScrollView(
         child: SafeArea(child: CourseTemplatePageBody()),
       ),
@@ -227,7 +227,7 @@ class CreateCustomCourseSection extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return Container(
-      color: isDarkThemeEnabled(context)
+      color: Theme.of(context).isDarkTheme
           ? Theme.of(context).scaffoldBackgroundColor
           : Colors.grey[100],
       child: SafeArea(

app/lib/groups/src/pages/course/group_help.dart

@@ -126,7 +126,7 @@ class _HowToJoinAGroupState extends State<_HowToJoinAGroup> {
             if (value) {
               setState(() {
                 // Expansion is open: so let's make the svg black
-                _svgColor = isDarkThemeEnabled(context)
+                _svgColor = Theme.of(context).isDarkTheme
                     ? Colors.white
                     : Theme.of(context).colorScheme.secondary;
               });
@@ -168,7 +168,7 @@ class _HowToJoinAGroupState extends State<_HowToJoinAGroup> {
             if (value) {
               setState(() {
                 // Expansion is open: so let's make the svg black
-                _typeInPublicKeyIconColor = isDarkThemeEnabled(context)
+                _typeInPublicKeyIconColor = Theme.of(context).isDarkTheme
                     ? Colors.white
                     : Theme.of(context).colorScheme.secondary;
               });

app/lib/groups/src/pages/course/group_page.dart

@@ -353,7 +353,7 @@ class _JoinGroupTile extends StatelessWidget {
             children: <Widget>[
               const SizedBox(width: 16),
               Icon(iconData,
-                  color: isDarkThemeEnabled(context)
+                  color: Theme.of(context).isDarkTheme
                       ? Colors.white54
                       : Colors.grey[600]),
               const SizedBox(width: 22),

app/lib/groups/src/widgets/member_list.dart

@@ -139,7 +139,7 @@ class MemberTile extends StatelessWidget {
           : withReportOption
               ? ReportIcon(
                   item: ReportItemReference.user(memberData.id.toString()),
-                  color: isDarkThemeEnabled(context)
+                  color: Theme.of(context).isDarkTheme
                       ? Colors.grey
                       : Colors.grey[600],
                 )

app/lib/groups/src/widgets/sharecode_text.dart

@@ -28,7 +28,7 @@ class SharecodeText extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final style = TextStyle(
-      color: isDarkThemeEnabled(context) ? Colors.white : Colors.black,
+      color: Theme.of(context).isDarkTheme ? Colors.white : Colors.black,
       fontSize: 22,
       fontWeight: FontWeight.w500,
     );

app/lib/homework/shared/homework_tab_bar.dart

@@ -21,7 +21,7 @@ class HomeworkTabBar extends StatelessWidget implements PreferredSizeWidget {
     Color indicatorColor;
     if (context != null) {
       indicatorColor =
-          isDarkThemeEnabled(context) ? primaryColor : darkBlueColor;
+          Theme.of(context).isDarkTheme ? primaryColor : darkBlueColor;
     } else {
       // Ist egal, weil es ohne Kontext nur für preferredSize genutzt werden sollte
       indicatorColor = primaryColor;

app/lib/homework/student/student_homework_page.dart

@@ -30,7 +30,7 @@ class StudentHomeworkPage extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final bottomBarBackgroundColor =
-        isDarkThemeEnabled(context) ? Colors.grey[900] : Colors.grey[100];
+        Theme.of(context).isDarkTheme ? Colors.grey[900] : Colors.grey[100];
     return ChangeNotifierProvider<BottomOfScrollViewInvisibilityController>(
       create: (_) => BottomOfScrollViewInvisibilityController(),
       child: WillPopScope(