diff --git a/lib/common/appstart/background_initialize.dart b/lib/common/appstart/background_initialize.dart
index 169b6196..6a3c4adf 100644
--- a/lib/common/appstart/background_initialize.dart
+++ b/lib/common/appstart/background_initialize.dart
@@ -9,7 +9,7 @@ import 'package:kiwi/kiwi.dart';
 
 class BackgroundInitialize {
   Future<void> setupBackgroundScheduling() async {
-    var scheduler;
+    WorkSchedulerService scheduler;
     if (Platform.isAndroid) {
       scheduler = BackgroundWorkScheduler();
     } else {
diff --git a/lib/common/background/background_work_scheduler.dart b/lib/common/background/background_work_scheduler.dart
index fb085800..602ffea7 100644
--- a/lib/common/background/background_work_scheduler.dart
+++ b/lib/common/background/background_work_scheduler.dart
@@ -5,12 +5,13 @@ import 'package:kiwi/kiwi.dart';
 import 'package:workmanager/workmanager.dart';
 
 class BackgroundWorkScheduler extends WorkSchedulerService {
-  Map<String, TaskCallback> _taskCallbacks = {};
+  final Map<String, TaskCallback> _taskCallbacks = {};
 
   BackgroundWorkScheduler() {
     _setupBackgroundScheduling();
   }
 
+  @override
   Future<void> scheduleOneShotTaskIn(
       Duration delay, String id, String name) async {
     print(
@@ -25,6 +26,7 @@ class BackgroundWorkScheduler extends WorkSchedulerService {
     );
   }
 
+  @override
   Future<void> scheduleOneShotTaskAt(
     DateTime date,
     String id,
@@ -33,11 +35,13 @@ class BackgroundWorkScheduler extends WorkSchedulerService {
     await scheduleOneShotTaskIn(date.difference(DateTime.now()), id, name);
   }
 
+  @override
   Future<void> cancelTask(String id) async {
     await Workmanager.cancelByUniqueName(id);
     print("Cancelled task $id");
   }
 
+  @override
   Future<void> schedulePeriodic(
     Duration delay,
     String id, [
@@ -60,10 +64,12 @@ class BackgroundWorkScheduler extends WorkSchedulerService {
     );
   }
 
+  @override
   void registerTask(TaskCallback task) {
     _taskCallbacks[task.getName()] = task;
   }
 
+  @override
   Future<void> executeTask(String id) async {
     await _taskCallbacks[id]?.run();
   }
diff --git a/lib/common/background/void_background_work_scheduler.dart b/lib/common/background/void_background_work_scheduler.dart
index 0e22d69a..6f1ee414 100644
--- a/lib/common/background/void_background_work_scheduler.dart
+++ b/lib/common/background/void_background_work_scheduler.dart
@@ -6,6 +6,7 @@ class VoidBackgroundWorkScheduler extends WorkSchedulerService {
     print("Background scheduling is not available!");
   }
 
+  @override
   Future<void> scheduleOneShotTaskIn(Duration delay, String id, String name) {
     print(
       "Did not schedule one shot task: $id. With a delay of ${delay.inMinutes} minutes.",
@@ -14,6 +15,7 @@ class VoidBackgroundWorkScheduler extends WorkSchedulerService {
     return Future.value();
   }
 
+  @override
   Future<void> scheduleOneShotTaskAt(
     DateTime date,
     String id,
@@ -22,12 +24,14 @@ class VoidBackgroundWorkScheduler extends WorkSchedulerService {
     await scheduleOneShotTaskIn(date.difference(DateTime.now()), id, name);
   }
 
+  @override
   Future<void> cancelTask(String id) {
     print("Cancelled task $id");
 
     return Future.value();
   }
 
+  @override
   Future<void> schedulePeriodic(
     Duration delay,
     String id, [
@@ -40,8 +44,10 @@ class VoidBackgroundWorkScheduler extends WorkSchedulerService {
     return Future.value();
   }
 
+  @override
   void registerTask(TaskCallback task) {}
 
+  @override
   Future<void> executeTask(String id) {
     return Future.value();
   }
diff --git a/lib/common/data/database_access.dart b/lib/common/data/database_access.dart
index 9cb431e5..9eec93c1 100644
--- a/lib/common/data/database_access.dart
+++ b/lib/common/data/database_access.dart
@@ -6,10 +6,10 @@ import 'package:path_provider/path_provider.dart';
 import 'package:sqflite/sqflite.dart';
 
 class DatabaseAccess {
-  static final _databaseName = "Database.db";
+  static const String _databaseName = "Database.db";
   static Database _databaseInstance;
 
-  static final String idColumnName = "id";
+  static const String idColumnName = "id";
 
   Future<Database> get _database async {
     if (_databaseInstance != null) return _databaseInstance;
@@ -18,9 +18,10 @@ class DatabaseAccess {
     return _databaseInstance;
   }
 
-  _initDatabase() async {
-    Directory documentsDirectory = await getApplicationDocumentsDirectory();
-    String path = join(documentsDirectory.path, _databaseName);
+  Future<Database> _initDatabase() async {
+    final Directory documentsDirectory =
+        await getApplicationDocumentsDirectory();
+    final String path = join(documentsDirectory.path, _databaseName);
 
     return await openDatabase(path,
         version: SqlScripts.databaseMigrationScripts.length,
@@ -28,13 +29,13 @@ class DatabaseAccess {
         onUpgrade: _onUpgrade);
   }
 
-  Future _onCreate(Database db, int version) async {
+  Future<void> _onCreate(Database db, int version) async {
     print("Initializing Database with version: $version");
 
     await _onUpgrade(db, 1, version);
   }
 
-  Future _onUpgrade(Database db, int oldVersion, int newVersion) async {
+  Future<void> _onUpgrade(Database db, int oldVersion, int newVersion) async {
     print("Migrating database version: $oldVersion -> $newVersion");
 
     for (var i = oldVersion; i <= newVersion; i++) {
diff --git a/lib/common/data/preferences/secure_storage_access.dart b/lib/common/data/preferences/secure_storage_access.dart
index 5ffe14fa..ec8e7442 100644
--- a/lib/common/data/preferences/secure_storage_access.dart
+++ b/lib/common/data/preferences/secure_storage_access.dart
@@ -1,7 +1,7 @@
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 
 class SecureStorageAccess {
-  final _secureStorage = new FlutterSecureStorage();
+  final _secureStorage = const FlutterSecureStorage();
 
   Future<void> set(String key, String value) async {
     await _secureStorage.write(key: key, value: value);
diff --git a/lib/common/i18n/localizations.dart b/lib/common/i18n/localizations.dart
index 453814e7..a555e50d 100644
--- a/lib/common/i18n/localizations.dart
+++ b/lib/common/i18n/localizations.dart
@@ -310,12 +310,12 @@ class L {
     return Localizations.of<L>(context, L);
   }
 
-  static Map<String, Map<String, String>> _localizedValues = {
+  static final Map<String, Map<String, String>> _localizedValues = {
     "de": de,
     "en": en
   };
 
-  _getValue(String key) {
+  String _getValue(String key) {
     return _localizedValues[_language][key] ?? "";
   }
 
diff --git a/lib/common/ui/colors.dart b/lib/common/ui/colors.dart
index f127c67e..a17ba1de 100644
--- a/lib/common/ui/colors.dart
+++ b/lib/common/ui/colors.dart
@@ -73,16 +73,16 @@ class ColorPalettes {
   }
 
   static const MaterialColor main = MaterialColor(0xffff061c, <int, Color>{
-    050: const Color(0xFFff838e),
-    100: const Color(0xFFff6a77),
-    200: const Color(0xFFff5160),
-    300: const Color(0xFFff3849),
-    400: const Color(0xFFff1f33),
-    500: const Color(0xffff061c),
-    600: const Color(0xFFe60519),
-    700: const Color(0xFFcc0516),
-    800: const Color(0xFFb30414),
-    900: const Color(0xFF990411),
+    050: Color(0xFFff838e),
+    100: Color(0xFFff6a77),
+    200: Color(0xFFff5160),
+    300: Color(0xFFff3849),
+    400: Color(0xFFff1f33),
+    500: Color(0xffff061c),
+    600: Color(0xFFe60519),
+    700: Color(0xFFcc0516),
+    800: Color(0xFFb30414),
+    900: Color(0xFF990411),
   });
 
   static const MaterialColor secondary = MaterialColor(0xFFCECED0, <int, Color>{
diff --git a/lib/common/ui/notification_api.dart b/lib/common/ui/notification_api.dart
index bb4b02f6..08f12a59 100644
--- a/lib/common/ui/notification_api.dart
+++ b/lib/common/ui/notification_api.dart
@@ -8,7 +8,7 @@ class NotificationApi {
       FlutterLocalNotificationsPlugin();
 
   Future<void> initialize() async {
-    var initializationSettingsAndroid = AndroidInitializationSettings(
+    var initializationSettingsAndroid = const AndroidInitializationSettings(
       'outline_event_note_24',
     );
 
@@ -44,7 +44,7 @@ class NotificationApi {
       ticker: 'ticker',
     );
 
-    var iOSPlatformChannelSpecifics = IOSNotificationDetails();
+    var iOSPlatformChannelSpecifics = const IOSNotificationDetails();
 
     var platformChannelSpecifics = NotificationDetails(
       androidPlatformChannelSpecifics,
diff --git a/lib/common/ui/rate_in_store.dart b/lib/common/ui/rate_in_store.dart
index 9ab6d61d..fab9a120 100644
--- a/lib/common/ui/rate_in_store.dart
+++ b/lib/common/ui/rate_in_store.dart
@@ -10,7 +10,8 @@ class RateInStore {
   RateInStore(this._preferencesProvider);
 
   Future<void> showRateInStoreDialogIfNeeded(BuildContext context) async {
-    var countdown = await _preferencesProvider.getRateInStoreLaunchCountdown();
+    final countdown =
+        await _preferencesProvider.getRateInStoreLaunchCountdown();
 
     if (countdown <= 0) {
       if (await _preferencesProvider.getDontShowRateNowDialog()) return;
@@ -27,15 +28,15 @@ class RateInStore {
       barrierDismissible: false,
       builder: (BuildContext context) {
         return AlertDialog(
-          buttonPadding: EdgeInsets.all(0),
-          actionsPadding: EdgeInsets.all(0),
-          contentPadding: EdgeInsets.all(0),
+          buttonPadding: const EdgeInsets.all(0),
+          actionsPadding: const EdgeInsets.all(0),
+          contentPadding: const EdgeInsets.all(0),
           title: Text(L.of(context).rateDialogTitle),
           content: Column(
             mainAxisSize: MainAxisSize.min,
             children: <Widget>[
               Padding(
-                padding: EdgeInsets.all(24),
+                padding: const EdgeInsets.all(24),
                 child: Text(L.of(context).rateDialogMessage),
               ),
               Padding(
@@ -52,7 +53,7 @@ class RateInStore {
   ButtonBar _buildButtonBar(BuildContext context) {
     return ButtonBar(
       mainAxisSize: MainAxisSize.max,
-      buttonPadding: EdgeInsets.fromLTRB(5, 0, 5, 0),
+      buttonPadding: const EdgeInsets.fromLTRB(5, 0, 5, 0),
       children: <Widget>[
         FlatButton(
           child: Text(L.of(context).rateDialogDoNotRateButton.toUpperCase()),
diff --git a/lib/common/ui/widgets/error_display.dart b/lib/common/ui/widgets/error_display.dart
index 38bd1968..6cefef8f 100644
--- a/lib/common/ui/widgets/error_display.dart
+++ b/lib/common/ui/widgets/error_display.dart
@@ -34,7 +34,7 @@ class ErrorDisplay extends StatelessWidget {
               : Container(
                   width: double.infinity,
                 ),
-          duration: Duration(milliseconds: 300),
+          duration: const Duration(milliseconds: 300),
         ),
       ],
     );
diff --git a/lib/common/util/cancelable_mutex.dart b/lib/common/util/cancelable_mutex.dart
index 8a540688..5335981a 100644
--- a/lib/common/util/cancelable_mutex.dart
+++ b/lib/common/util/cancelable_mutex.dart
@@ -2,7 +2,7 @@ import 'package:mutex/mutex.dart';
 import 'cancellation_token.dart';
 
 class CancelableMutex {
-  Mutex _mutex = Mutex();
+  final Mutex _mutex = Mutex();
   CancellationToken _token;
   CancellationToken get token => _token;
 
diff --git a/lib/date_management/data/calendar_access.dart b/lib/date_management/data/calendar_access.dart
index 16300fb4..66fb76e3 100644
--- a/lib/date_management/data/calendar_access.dart
+++ b/lib/date_management/data/calendar_access.dart
@@ -51,7 +51,7 @@ class CalendarAccess {
     List<DateEntry> dateEntries,
     Calendar calendar,
   ) async {
-    if ((dateEntries ?? []).length == 0) return;
+    if ((dateEntries ?? []).isEmpty) return;
 
     var existingEvents =
         await _getExistingEventsFromCalendar(dateEntries, calendar);
@@ -70,7 +70,7 @@ class CalendarAccess {
     var isAllDay = isAtMidnight(entry.dateAndTime);
 
     var start = entry.dateAndTime;
-    var end = isAllDay ? start : start.add(Duration(minutes: 30));
+    var end = isAllDay ? start : start.add(const Duration(minutes: 30));
 
     await _deviceCalendarPlugin.createOrUpdateEvent(Event(
       calendar.id,
@@ -90,9 +90,9 @@ class CalendarAccess {
         .where((element) => element.title == entry.description)
         .toList();
 
-    var id;
+    String id;
 
-    if (existingEvent.length > 0) {
+    if (existingEvent.isNotEmpty) {
       id = existingEvent[0].eventId;
     }
     return id;
diff --git a/lib/date_management/data/date_entry_entity.dart b/lib/date_management/data/date_entry_entity.dart
index 8d0ee44f..3c82cc13 100644
--- a/lib/date_management/data/date_entry_entity.dart
+++ b/lib/date_management/data/date_entry_entity.dart
@@ -14,12 +14,12 @@ class DateEntryEntity extends DatabaseEntity {
 
   @override
   void fromMap(Map<String, dynamic> map) {
-    var date;
+    DateTime date;
     if (map["date"] != null) {
       date = DateTime.fromMillisecondsSinceEpoch(map["date"]);
     }
 
-    _dateEntry = new DateEntry(
+    _dateEntry = DateEntry(
       comment: map["comment"],
       dateAndTime: date,
       description: map["description"],
diff --git a/lib/date_management/data/date_entry_repository.dart b/lib/date_management/data/date_entry_repository.dart
index 9c975f14..7a4f675b 100644
--- a/lib/date_management/data/date_entry_repository.dart
+++ b/lib/date_management/data/date_entry_repository.dart
@@ -104,7 +104,7 @@ class DateEntryRepository {
 
     for (var row in rows) {
       dateEntries.add(
-        new DateEntryEntity.fromMap(row).asDateEntry(),
+        DateEntryEntity.fromMap(row).asDateEntry(),
       );
     }
 
diff --git a/lib/date_management/service/parsing/all_dates_extract.dart b/lib/date_management/service/parsing/all_dates_extract.dart
index 511369a5..3a4e01b4 100644
--- a/lib/date_management/service/parsing/all_dates_extract.dart
+++ b/lib/date_management/service/parsing/all_dates_extract.dart
@@ -10,7 +10,7 @@ class AllDatesExtract {
       return _extractAllDates(body, databaseName);
     } catch (e) {
       if (e.runtimeType is ParseException) rethrow;
-      throw new ParseException.withInner(e);
+      throw ParseException.withInner(e);
     }
   }
 
diff --git a/lib/date_management/ui/calendar_export_page.dart b/lib/date_management/ui/calendar_export_page.dart
index f58cf0e1..b120e11a 100644
--- a/lib/date_management/ui/calendar_export_page.dart
+++ b/lib/date_management/ui/calendar_export_page.dart
@@ -60,7 +60,7 @@ class _CalendarExportPageState extends State<CalendarExportPage> {
                       L.of(context).dateManagementExportToCalendarDescription)),
             ),
             _buildCalendarList(),
-            Divider(
+            const Divider(
               height: 1,
             ),
             _buildExportButton()
@@ -106,7 +106,7 @@ class _CalendarExportPageState extends State<CalendarExportPage> {
             Container(
               width: 24,
               height: 24,
-              decoration: new BoxDecoration(
+              decoration: BoxDecoration(
                 shape: BoxShape.circle,
                 color: isSelected ? Color(calendar.color) : Colors.transparent,
                 border: Border.all(
@@ -143,8 +143,8 @@ class _CalendarExportPageState extends State<CalendarExportPage> {
           builder:
               (BuildContext context, CalendarExportViewModel viewModel, _) =>
                   viewModel.isExporting
-                      ? Padding(
-                          padding: const EdgeInsets.all(8.0),
+                      ? const Padding(
+                          padding: EdgeInsets.all(8.0),
                           child: SizedBox(
                               height: 32,
                               width: 32,
diff --git a/lib/date_management/ui/date_management_page.dart b/lib/date_management/ui/date_management_page.dart
index 37ab8f35..815271cf 100644
--- a/lib/date_management/ui/date_management_page.dart
+++ b/lib/date_management/ui/date_management_page.dart
@@ -25,11 +25,11 @@ class DateManagementPage extends StatelessWidget {
           DateFilterOptions(viewModel: viewModel),
           Stack(
             children: <Widget>[
-              Divider(),
+              const Divider(),
               AnimatedSwitcher(
-                  duration: Duration(milliseconds: 200),
+                  duration: const Duration(milliseconds: 200),
                   child: viewModel.isLoading
-                      ? LinearProgressIndicator()
+                      ? const LinearProgressIndicator()
                       : Container()),
             ],
           ),
@@ -52,7 +52,7 @@ class DateManagementPage extends StatelessWidget {
                 _,
               ) =>
                   AnimatedSwitcher(
-                      duration: Duration(milliseconds: 200),
+                      duration: const Duration(milliseconds: 200),
                       child: Column(
                         key: ValueKey(
                             viewModel?.dateSearchParameters?.toString() ?? ""),
@@ -146,7 +146,7 @@ class DateManagementPage extends StatelessWidget {
       builder: (context) => DateDetailBottomSheet(
         dateEntry: entry,
       ),
-      shape: RoundedRectangleBorder(
+      shape: const RoundedRectangleBorder(
         borderRadius: BorderRadius.vertical(top: Radius.circular(12.0)),
       ),
     );
@@ -154,7 +154,7 @@ class DateManagementPage extends StatelessWidget {
 
   Widget buildErrorDisplay(BuildContext context) {
     return PropertyChangeConsumer(
-      properties: [
+      properties: const [
         "updateFailed",
       ],
       builder: (BuildContext context, DateManagementViewModel model,
diff --git a/lib/date_management/ui/viewmodels/date_management_view_model.dart b/lib/date_management/ui/viewmodels/date_management_view_model.dart
index d2387734..2c4b1765 100644
--- a/lib/date_management/ui/viewmodels/date_management_view_model.dart
+++ b/lib/date_management/ui/viewmodels/date_management_view_model.dart
@@ -198,7 +198,7 @@ class DateManagementViewModel extends BaseViewModel {
     }
 
     _errorResetTimer = Timer(
-      Duration(seconds: 5),
+      const Duration(seconds: 5),
       () {
         _updateFailed = false;
         notifyListeners("updateFailed");
diff --git a/lib/date_management/ui/widgets/date_detail_bottom_sheet.dart b/lib/date_management/ui/widgets/date_detail_bottom_sheet.dart
index d3dbffb1..48dfdaad 100644
--- a/lib/date_management/ui/widgets/date_detail_bottom_sheet.dart
+++ b/lib/date_management/ui/widgets/date_detail_bottom_sheet.dart
@@ -32,10 +32,9 @@ class DateDetailBottomSheet extends StatelessWidget {
                 child: Container(
                   height: 8,
                   width: 30,
-                  decoration: new BoxDecoration(
+                  decoration: BoxDecoration(
                       color: colorSeparator(),
-                      borderRadius:
-                          new BorderRadius.all(const Radius.circular(4))),
+                      borderRadius: const BorderRadius.all(Radius.circular(4))),
                   child: null,
                 ),
               ),
diff --git a/lib/date_management/ui/widgets/date_filter_options.dart b/lib/date_management/ui/widgets/date_filter_options.dart
index 9ce30ff6..3d620202 100644
--- a/lib/date_management/ui/widgets/date_filter_options.dart
+++ b/lib/date_management/ui/widgets/date_filter_options.dart
@@ -25,7 +25,7 @@ class _DateFilterOptionsState extends State<DateFilterOptions> {
     return AnimatedCrossFade(
       secondChild: _fixAbsorbPointer(_buildExpanded()),
       firstChild: _fixAbsorbPointer(_buildCollapsed()),
-      duration: Duration(milliseconds: 200),
+      duration: const Duration(milliseconds: 200),
       crossFadeState:
           _isExpanded ? CrossFadeState.showSecond : CrossFadeState.showFirst,
     );
@@ -37,7 +37,7 @@ class _DateFilterOptionsState extends State<DateFilterOptions> {
     // More details here: https://github.com/flutter/flutter/issues/10168
     return Stack(
       children: [
-        Positioned.fill(
+        const Positioned.fill(
           child: AbsorbPointer(),
         ),
         widget
@@ -66,7 +66,7 @@ class _DateFilterOptionsState extends State<DateFilterOptions> {
               height: 36,
               child: FlatButton(
                 child: Icon(Icons.tune),
-                padding: EdgeInsets.all(0),
+                padding: const EdgeInsets.all(0),
                 materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
                 onPressed: () {
                   setState(() {
@@ -208,8 +208,8 @@ class _DateFilterOptionsState extends State<DateFilterOptions> {
             minWidth: 36,
             height: 36,
             child: FlatButton(
-              child: Icon(Icons.check),
-              padding: EdgeInsets.all(0),
+              child: const Icon(Icons.check),
+              padding: const EdgeInsets.all(0),
               materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
               onPressed: () {
                 setState(() {
diff --git a/lib/dualis/service/dualis_scraper.dart b/lib/dualis/service/dualis_scraper.dart
index f84dc299..736d9300 100644
--- a/lib/dualis/service/dualis_scraper.dart
+++ b/lib/dualis/service/dualis_scraper.dart
@@ -13,7 +13,7 @@ import 'package:dhbwstudentapp/schedule/service/schedule_source.dart';
 import 'package:http/http.dart';
 
 class DualisScraper {
-  static final String dualisEndpoint = "https://dualis.dhbw.de";
+  static const String dualisEndpoint = "https://dualis.dhbw.de";
 
   Future<DualisSession> login(
     String user,
diff --git a/lib/dualis/service/parsing/all_modules_extract.dart b/lib/dualis/service/parsing/all_modules_extract.dart
index 2cdff162..81bd1e06 100644
--- a/lib/dualis/service/parsing/all_modules_extract.dart
+++ b/lib/dualis/service/parsing/all_modules_extract.dart
@@ -10,7 +10,7 @@ class AllModulesExtract {
       return _extractAllModules(body);
     } catch (e) {
       if (e.runtimeType is ParseException) rethrow;
-      throw new ParseException.withInner(e);
+      throw ParseException.withInner(e);
     }
   }
 
@@ -40,7 +40,7 @@ class AllModulesExtract {
     var name = cells[1].innerHtml.trim();
     var nameHyperlink = cells[1].getElementsByTagName("a");
 
-    if (nameHyperlink.length != 0) {
+    if (nameHyperlink.isNotEmpty) {
       name = nameHyperlink[0].innerHtml;
     }
 
@@ -49,7 +49,7 @@ class AllModulesExtract {
     var grade = cells[4].innerHtml;
     var state = cells[5].children[0].attributes["alt"];
 
-    var stateEnum;
+    ExamState stateEnum;
 
     if (state == "Bestanden") {
       stateEnum = ExamState.Passed;
diff --git a/lib/dualis/service/parsing/exams_from_module_details_extract.dart b/lib/dualis/service/parsing/exams_from_module_details_extract.dart
index 52895ea9..f592e4d3 100644
--- a/lib/dualis/service/parsing/exams_from_module_details_extract.dart
+++ b/lib/dualis/service/parsing/exams_from_module_details_extract.dart
@@ -26,14 +26,14 @@ class ExamsFromModuleDetailsExtract {
     for (var row in tableExamsRows) {
       // Save the try for all following exams
       var level01s = row.getElementsByClassName("level01");
-      if (level01s.length > 0) {
+      if (level01s.isNotEmpty) {
         currentTry = level01s[0].innerHtml;
         continue;
       }
 
       // Save the module for all following exams
       var level02s = row.getElementsByClassName("level02");
-      if (level02s.length > 0) {
+      if (level02s.isNotEmpty) {
         currentModule = level02s[0].innerHtml;
         continue;
       }
diff --git a/lib/dualis/service/parsing/login_redirect_url_extract.dart b/lib/dualis/service/parsing/login_redirect_url_extract.dart
index bf088fb3..847edff5 100644
--- a/lib/dualis/service/parsing/login_redirect_url_extract.dart
+++ b/lib/dualis/service/parsing/login_redirect_url_extract.dart
@@ -6,7 +6,7 @@ class LoginRedirectUrlExtract {
 
     var metaTags = document.getElementsByTagName("meta");
 
-    var redirectContent;
+    String redirectContent;
 
     for (var metaTag in metaTags) {
       if (!metaTag.attributes.containsKey("http-equiv")) continue;
diff --git a/lib/dualis/service/parsing/modules_from_course_result_page_extract.dart b/lib/dualis/service/parsing/modules_from_course_result_page_extract.dart
index 31a11c85..bb1ca1e8 100644
--- a/lib/dualis/service/parsing/modules_from_course_result_page_extract.dart
+++ b/lib/dualis/service/parsing/modules_from_course_result_page_extract.dart
@@ -55,7 +55,7 @@ class ModulesFromCourseResultPageExtract {
 
     status = trimAndEscapeString(status);
 
-    var statusEnum;
+    ExamState statusEnum;
 
     if (status == "bestanden") {
       statusEnum = ExamState.Passed;
diff --git a/lib/dualis/service/parsing/semesters_from_course_result_page_extract.dart b/lib/dualis/service/parsing/semesters_from_course_result_page_extract.dart
index f9b62b7b..bca07e91 100644
--- a/lib/dualis/service/parsing/semesters_from_course_result_page_extract.dart
+++ b/lib/dualis/service/parsing/semesters_from_course_result_page_extract.dart
@@ -32,7 +32,7 @@ class SemestersFromCourseResultPageExtract {
       var id = option.attributes["value"];
       var name = option.innerHtml;
 
-      var detailsUrl;
+      String detailsUrl;
 
       if (url != null) {
         detailsUrl = url + id;
diff --git a/lib/dualis/ui/dualis_navigation_entry.dart b/lib/dualis/ui/dualis_navigation_entry.dart
index a7c3ce6a..2169d633 100644
--- a/lib/dualis/ui/dualis_navigation_entry.dart
+++ b/lib/dualis/ui/dualis_navigation_entry.dart
@@ -56,7 +56,7 @@ class DualisNavigationEntry extends NavigationEntry {
                       tooltip: L.of(context).helpButtonTooltip,
                     )
                   : IconButton(
-                      icon: Icon(CustomIcons.logout),
+                      icon: const Icon(CustomIcons.logout),
                       onPressed: () async {
                         await _viewModel.logout();
                       },
diff --git a/lib/dualis/ui/dualis_page.dart b/lib/dualis/ui/dualis_page.dart
index cbe28871..1c477dda 100644
--- a/lib/dualis/ui/dualis_page.dart
+++ b/lib/dualis/ui/dualis_page.dart
@@ -40,7 +40,7 @@ class DualisPage extends StatelessWidget {
     }
 
     return AnimatedSwitcher(
-      duration: Duration(milliseconds: 200),
+      duration: const Duration(milliseconds: 200),
       child: widget,
     );
   }
diff --git a/lib/dualis/ui/exam_results_page/exam_results_page.dart b/lib/dualis/ui/exam_results_page/exam_results_page.dart
index 83f6aabd..e8a28b56 100644
--- a/lib/dualis/ui/exam_results_page/exam_results_page.dart
+++ b/lib/dualis/ui/exam_results_page/exam_results_page.dart
@@ -31,7 +31,7 @@ class ExamResultsPage extends StatelessWidget {
                   Padding(
                     padding: const EdgeInsets.fromLTRB(24, 0, 0, 0),
                     child: PropertyChangeConsumer(
-                      properties: [
+                      properties: const [
                         "currentSemesterName",
                         "allSemesterNames",
                       ],
@@ -58,7 +58,7 @@ class ExamResultsPage extends StatelessWidget {
               ),
             ),
             PropertyChangeConsumer(
-              properties: ["currentSemester"],
+              properties: const ["currentSemester"],
               builder: (
                 BuildContext context,
                 StudyGradesViewModel model,
@@ -66,8 +66,8 @@ class ExamResultsPage extends StatelessWidget {
               ) =>
                   model.currentSemester != null
                       ? buildModulesColumn(context, model)
-                      : Padding(
-                          padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
+                      : const Padding(
+                          padding: EdgeInsets.fromLTRB(0, 16, 0, 0),
                           child: Center(child: CircularProgressIndicator()),
                         ),
             ),
@@ -93,7 +93,7 @@ class ExamResultsPage extends StatelessWidget {
         key: ValueKey("semester_${viewModel.currentSemester?.name}"),
         children: buildModulesDataTables(context, viewModel),
       ),
-      duration: Duration(milliseconds: 200),
+      duration: const Duration(milliseconds: 200),
     );
   }
 
@@ -163,7 +163,7 @@ class ExamResultsPage extends StatelessWidget {
           child: Align(
             alignment: Alignment.bottomLeft,
             child: Padding(
-              padding: EdgeInsets.fromLTRB(0, 0, 10, 16),
+              padding: const EdgeInsets.fromLTRB(0, 0, 10, 16),
               child: Text(
                 (module.name ?? ""),
                 style: Theme.of(context).textTheme.subtitle2,
@@ -182,7 +182,7 @@ class ExamResultsPage extends StatelessWidget {
           child: Align(
             alignment: Alignment.bottomLeft,
             child: Padding(
-              padding: EdgeInsets.fromLTRB(0, 0, 10, 16),
+              padding: const EdgeInsets.fromLTRB(0, 0, 10, 16),
               child: Text(
                   "${L.of(context).dualisExamResultsCreditsColumnHeader}:  ${module.credits}"),
             ),
diff --git a/lib/dualis/ui/study_overview/study_overview_page.dart b/lib/dualis/ui/study_overview/study_overview_page.dart
index b731af4c..1cd0f267 100644
--- a/lib/dualis/ui/study_overview/study_overview_page.dart
+++ b/lib/dualis/ui/study_overview/study_overview_page.dart
@@ -36,7 +36,7 @@ class StudyOverviewPage extends StatelessWidget {
             style: Theme.of(context).textTheme.headline6,
           ),
           PropertyChangeConsumer(
-            properties: ["studyGrades"],
+            properties: const ["studyGrades"],
             builder: (
               BuildContext context,
               StudyGradesViewModel model,
@@ -126,7 +126,7 @@ class StudyOverviewPage extends StatelessWidget {
             ),
           ),
           PropertyChangeConsumer(
-            properties: ["allModules"],
+            properties: const ["allModules"],
             builder: (
               BuildContext context,
               StudyGradesViewModel model,
@@ -142,8 +142,8 @@ class StudyOverviewPage extends StatelessWidget {
   }
 
   Padding buildProgressIndicator() {
-    return Padding(
-      padding: const EdgeInsets.all(24),
+    return const Padding(
+      padding: EdgeInsets.all(24),
       child: Center(child: CircularProgressIndicator()),
     );
   }
@@ -190,7 +190,7 @@ class StudyOverviewPage extends StatelessWidget {
         numeric: true,
       ),
       DataColumn(
-        label: Text(""),
+        label: const Text(""),
         numeric: true,
         tooltip: L.of(context).dualisOverviewPassedColumnHeader,
       ),
diff --git a/lib/dualis/ui/viewmodels/study_grades_view_model.dart b/lib/dualis/ui/viewmodels/study_grades_view_model.dart
index aa46977e..9235d7c8 100644
--- a/lib/dualis/ui/viewmodels/study_grades_view_model.dart
+++ b/lib/dualis/ui/viewmodels/study_grades_view_model.dart
@@ -26,19 +26,19 @@ class StudyGradesViewModel extends BaseViewModel {
 
   StudyGrades _studyGrades;
   StudyGrades get studyGrades => _studyGrades;
-  CancelableMutex _studyGradesCancellationToken = CancelableMutex();
+  final CancelableMutex _studyGradesCancellationToken = CancelableMutex();
 
   List<Module> _allModules;
   List<Module> get allModules => _allModules;
-  CancelableMutex _allModulesCancellationToken = CancelableMutex();
+  final CancelableMutex _allModulesCancellationToken = CancelableMutex();
 
   List<String> _semesterNames;
   List<String> get allSemesterNames => _semesterNames;
-  CancelableMutex _semesterNamesCancellationToken = CancelableMutex();
+  final CancelableMutex _semesterNamesCancellationToken = CancelableMutex();
 
   Semester _currentSemester;
   Semester get currentSemester => _currentSemester;
-  CancelableMutex _currentSemesterCancellationToken = CancelableMutex();
+  final CancelableMutex _currentSemesterCancellationToken = CancelableMutex();
 
   String _currentSemesterName;
   String get currentSemesterName => _currentSemesterName;
@@ -200,7 +200,7 @@ class StudyGradesViewModel extends BaseViewModel {
 
   Future _loadInitialSemester() async {
     if (_semesterNames == null) return;
-    if (_semesterNames.length == 0) return;
+    if (_semesterNames.isEmpty) return;
 
     var lastViewedSemester = await _preferencesProvider.getLastViewedSemester();
 
@@ -231,7 +231,7 @@ class StudyGradesViewModel extends BaseViewModel {
     _currentSemester = null;
     _currentSemesterName = null;
     _currentLoadingSemesterName = null;
-    
+
     notifyListeners();
 
     print("Logged out");
diff --git a/lib/dualis/ui/widgets/grade_state_icon.dart b/lib/dualis/ui/widgets/grade_state_icon.dart
index 4cee7f66..8c3e1236 100644
--- a/lib/dualis/ui/widgets/grade_state_icon.dart
+++ b/lib/dualis/ui/widgets/grade_state_icon.dart
@@ -13,9 +13,9 @@ class GradeStateIcon extends StatelessWidget {
   Widget build(BuildContext context) {
     switch (state) {
       case ExamState.Passed:
-        return Icon(Icons.check, color: Colors.green);
+        return const Icon(Icons.check, color: Colors.green);
       case ExamState.Failed:
-        return Icon(Icons.close, color: Colors.red);
+        return const Icon(Icons.close, color: Colors.red);
       case ExamState.Pending:
         return Container();
     }
diff --git a/lib/dualis/ui/widgets/login_form_widget.dart b/lib/dualis/ui/widgets/login_form_widget.dart
index 802841b8..507e6961 100644
--- a/lib/dualis/ui/widgets/login_form_widget.dart
+++ b/lib/dualis/ui/widgets/login_form_widget.dart
@@ -55,8 +55,10 @@ class _LoginFormState extends State<LoginForm> {
   bool _loginFailed = false;
   bool _isLoading = false;
 
-  TextEditingController _usernameEditingController = TextEditingController();
-  TextEditingController _passwordEditingController = TextEditingController();
+  final TextEditingController _usernameEditingController =
+      TextEditingController();
+  final TextEditingController _passwordEditingController =
+      TextEditingController();
 
   _LoginFormState(
     this._onLogin,
@@ -143,7 +145,7 @@ class _LoginFormState extends State<LoginForm> {
             child: Padding(
               padding: const EdgeInsets.fromLTRB(0, 24, 0, 0),
               child: _isLoading
-                  ? CircularProgressIndicator()
+                  ? const CircularProgressIndicator()
                   : FlatButton.icon(
                       textColor: Theme.of(context).accentColor,
                       onPressed: () async {
diff --git a/lib/schedule/background/background_schedule_update.dart b/lib/schedule/background/background_schedule_update.dart
index 5c270487..4e2af319 100644
--- a/lib/schedule/background/background_schedule_update.dart
+++ b/lib/schedule/background/background_schedule_update.dart
@@ -63,7 +63,7 @@ class BackgroundScheduleUpdate extends TaskCallback {
   @override
   Future<void> schedule() async {
     await scheduler.schedulePeriodic(
-      Duration(hours: 4),
+      const Duration(hours: 4),
       getName(),
     );
   }
diff --git a/lib/schedule/business/schedule_diff_calculator.dart b/lib/schedule/business/schedule_diff_calculator.dart
index 312909cd..077bdc17 100644
--- a/lib/schedule/business/schedule_diff_calculator.dart
+++ b/lib/schedule/business/schedule_diff_calculator.dart
@@ -75,12 +75,12 @@ class ScheduleDiffCalculator {
         (ScheduleEntry e) => e.title == intersectingTitle,
       );
 
-      if (newElementsWithName.length == 0 && oldElementsWithName.length >= 1) {
+      if (newElementsWithName.isEmpty && oldElementsWithName.isNotEmpty) {
         oldEntries.addAll(oldElementsWithName);
         continue;
       }
 
-      if (oldElementsWithName.length == 0 && newElementsWithName.length >= 1) {
+      if (oldElementsWithName.isEmpty && newElementsWithName.isNotEmpty) {
         newEntries.addAll(newElementsWithName);
         continue;
       }
@@ -169,9 +169,9 @@ class ScheduleDiff {
   ScheduleDiff({this.addedEntries, this.removedEntries, this.updatedEntries});
 
   bool didSomethingChange() {
-    return addedEntries.length != 0 ||
-        removedEntries.length != 0 ||
-        updatedEntries.length != 0;
+    return addedEntries.isNotEmpty ||
+        removedEntries.isNotEmpty ||
+        updatedEntries.isNotEmpty;
   }
 }
 
diff --git a/lib/schedule/data/schedule_entry_entity.dart b/lib/schedule/data/schedule_entry_entity.dart
index c533bc76..2f532d8f 100644
--- a/lib/schedule/data/schedule_entry_entity.dart
+++ b/lib/schedule/data/schedule_entry_entity.dart
@@ -14,17 +14,17 @@ class ScheduleEntryEntity extends DatabaseEntity {
 
   @override
   void fromMap(Map<String, dynamic> map) {
-    var startDate;
+    DateTime startDate;
     if (map["start"] != null) {
       startDate = DateTime.fromMillisecondsSinceEpoch(map["start"]);
     }
 
-    var endDate;
+    DateTime endDate;
     if (map["end"] != null) {
       endDate = DateTime.fromMillisecondsSinceEpoch(map["end"]);
     }
 
-    _scheduleEntry = new ScheduleEntry(
+    _scheduleEntry = ScheduleEntry(
         id: map["id"],
         start: startDate,
         end: endDate,
diff --git a/lib/schedule/data/schedule_entry_repository.dart b/lib/schedule/data/schedule_entry_repository.dart
index b31304e0..029c0013 100644
--- a/lib/schedule/data/schedule_entry_repository.dart
+++ b/lib/schedule/data/schedule_entry_repository.dart
@@ -9,7 +9,7 @@ class ScheduleEntryRepository {
   ScheduleEntryRepository(this._database);
 
   Future<Schedule> queryScheduleForDay(DateTime date) async {
-    return queryScheduleBetweenDates(date, date.add(Duration(days: 1)));
+    return queryScheduleBetweenDates(date, date.add(const Duration(days: 1)));
   }
 
   Future<Schedule> queryScheduleBetweenDates(
@@ -27,7 +27,7 @@ class ScheduleEntryRepository {
 
     for (var row in rows) {
       schedule.addEntry(
-        new ScheduleEntryEntity.fromMap(row).asScheduleEntry(),
+        ScheduleEntryEntity.fromMap(row).asScheduleEntry(),
       );
     }
 
@@ -47,9 +47,9 @@ class ScheduleEntryRepository {
       ],
     );
 
-    if (rows.length == 0) return null;
+    if (rows.isEmpty) return null;
 
-    return new ScheduleEntryEntity.fromMap(rows[0]).asScheduleEntry();
+    return ScheduleEntryEntity.fromMap(rows[0]).asScheduleEntry();
   }
 
   Future<ScheduleEntry> queryNextScheduleEntry(DateTime dateTime) async {
diff --git a/lib/schedule/data/schedule_query_information_entity.dart b/lib/schedule/data/schedule_query_information_entity.dart
index 329a4c2d..abd0d5e2 100644
--- a/lib/schedule/data/schedule_query_information_entity.dart
+++ b/lib/schedule/data/schedule_query_information_entity.dart
@@ -16,23 +16,23 @@ class ScheduleQueryInformationEntity extends DatabaseEntity {
 
   @override
   void fromMap(Map<String, dynamic> map) {
-    var startDate;
+    DateTime startDate;
     if (map["start"] != null) {
       startDate = DateTime.fromMillisecondsSinceEpoch(map["start"]);
     }
 
-    var endDate;
+    DateTime endDate;
     if (map["end"] != null) {
       endDate = DateTime.fromMillisecondsSinceEpoch(map["end"]);
     }
 
-    var queryTimeDate;
+    DateTime queryTimeDate;
     if (map["end"] != null) {
       queryTimeDate = DateTime.fromMillisecondsSinceEpoch(map["queryTime"]);
     }
 
     _scheduleQueryInformation =
-        new ScheduleQueryInformation(startDate, endDate, queryTimeDate);
+        ScheduleQueryInformation(startDate, endDate, queryTimeDate);
   }
 
   @override
diff --git a/lib/schedule/model/schedule.dart b/lib/schedule/model/schedule.dart
index d97a321d..450637d7 100644
--- a/lib/schedule/model/schedule.dart
+++ b/lib/schedule/model/schedule.dart
@@ -3,7 +3,7 @@ import 'package:dhbwstudentapp/schedule/model/schedule_entry.dart';
 class Schedule {
   final List<ScheduleEntry> entries;
 
-  Schedule() : entries = List<ScheduleEntry>();
+  Schedule() : entries = <ScheduleEntry>[];
   Schedule.fromList(this.entries);
 
   void addEntry(ScheduleEntry entry) {
@@ -28,7 +28,7 @@ class Schedule {
   }
 
   DateTime getStartDate() {
-    if (entries.length == 0) return null;
+    if (entries.isEmpty) return null;
 
     var date = entries?.reduce((ScheduleEntry a, ScheduleEntry b) {
       return a.start.isBefore(b.start) ? a : b;
@@ -38,7 +38,7 @@ class Schedule {
   }
 
   DateTime getEndDate() {
-    if (entries.length == 0) return null;
+    if (entries.isEmpty) return null;
 
     var date = entries?.reduce((ScheduleEntry a, ScheduleEntry b) {
       return a.end.isAfter(b.end) ? a : b;
diff --git a/lib/schedule/service/error_report_schedule_source_decorator.dart b/lib/schedule/service/error_report_schedule_source_decorator.dart
index eaad2112..7671de8c 100644
--- a/lib/schedule/service/error_report_schedule_source_decorator.dart
+++ b/lib/schedule/service/error_report_schedule_source_decorator.dart
@@ -34,8 +34,10 @@ class ErrorReportScheduleSourceDecorator extends ScheduleSource {
     }
   }
 
+  @override
   void setEndpointUrl(String url) => _scheduleSource.setEndpointUrl(url);
 
+  @override
   void validateEndpointUrl(String url) =>
       _scheduleSource.validateEndpointUrl(url);
 }
diff --git a/lib/schedule/service/rapla/rapla_response_parser.dart b/lib/schedule/service/rapla/rapla_response_parser.dart
index 0cea4133..17bad382 100644
--- a/lib/schedule/service/rapla/rapla_response_parser.dart
+++ b/lib/schedule/service/rapla/rapla_response_parser.dart
@@ -95,7 +95,7 @@ class RaplaResponseParser {
     // selected year in the date selector
     var comboBoxes = document.getElementsByTagName("select");
 
-    var year;
+    String year;
     for (var box in comboBoxes) {
       if (box.attributes.containsKey("name") &&
           box.attributes["name"] == "year") {
@@ -129,7 +129,7 @@ class RaplaResponseParser {
     var timeAndClassName = value.getElementsByTagName("a");
 
     if (tooltip.length != 1) return null;
-    if (timeAndClassName.length == 0) return null;
+    if (timeAndClassName.isEmpty) return null;
 
     var start = _parseTime(timeAndClassName[0].text.substring(0, 5), date);
     var end = _parseTime(timeAndClassName[0].text.substring(7, 12), date);
@@ -167,7 +167,7 @@ class RaplaResponseParser {
 
     var resource = _extractResources(value);
 
-    var scheduleEntry = new ScheduleEntry(
+    var scheduleEntry = ScheduleEntry(
       start: start,
       end: end,
       title: trimAndEscapeString(title),
@@ -193,7 +193,7 @@ class RaplaResponseParser {
   }
 
   Map<String, String> _parsePropertiesTable(Element infotable) {
-    var map = Map<String, String>();
+    var map = <String, String>{};
     var labels = infotable.getElementsByClassName(LABEL_CLASS);
     var values = infotable.getElementsByClassName(VALUE_CLASS);
 
diff --git a/lib/schedule/service/rapla/rapla_schedule_source.dart b/lib/schedule/service/rapla/rapla_schedule_source.dart
index 7ac13bd2..b4afd933 100644
--- a/lib/schedule/service/rapla/rapla_schedule_source.dart
+++ b/lib/schedule/service/rapla/rapla_schedule_source.dart
@@ -7,12 +7,13 @@ import 'package:http/http.dart';
 import 'package:http_client_helper/http_client_helper.dart' as http;
 
 class RaplaScheduleSource extends ScheduleSource {
-  final RaplaResponseParser responseParser = new RaplaResponseParser();
+  final RaplaResponseParser responseParser = RaplaResponseParser();
 
   String raplaUrl;
 
   RaplaScheduleSource({this.raplaUrl});
 
+  @override
   void setEndpointUrl(String url) {
     raplaUrl = url;
   }
diff --git a/lib/schedule/ui/dailyschedule/widgets/daily_schedule_entry_widget.dart b/lib/schedule/ui/dailyschedule/widgets/daily_schedule_entry_widget.dart
index 45c5db3d..9c0fe1e1 100644
--- a/lib/schedule/ui/dailyschedule/widgets/daily_schedule_entry_widget.dart
+++ b/lib/schedule/ui/dailyschedule/widgets/daily_schedule_entry_widget.dart
@@ -58,7 +58,7 @@ class DailyScheduleEntryWidget extends StatelessWidget {
           Expanded(
             flex: 7,
             child: Card(
-              margin: EdgeInsets.all(0),
+              margin: const EdgeInsets.all(0),
               elevation: 8,
               color: scheduleEntryTypeToColor(context, scheduleEntry.type),
               child: Padding(
diff --git a/lib/schedule/ui/notification/next_day_information_notification.dart b/lib/schedule/ui/notification/next_day_information_notification.dart
index 2b07d2b4..9ba2e251 100644
--- a/lib/schedule/ui/notification/next_day_information_notification.dart
+++ b/lib/schedule/ui/notification/next_day_information_notification.dart
@@ -51,9 +51,9 @@ class NextDayInformationNotification extends TaskCallback {
     );
   }
 
-  _getNotificationMessage(
+  String _getNotificationMessage(
       int daysToNextEntry, ScheduleEntry nextScheduleEntry, DateFormat format) {
-    var message;
+    String message;
     if (daysToNextEntry == 0) {
       message = interpolate(
         _localization.notificationNextClassNextClassAtMessage,
diff --git a/lib/schedule/ui/schedule_navigation_entry.dart b/lib/schedule/ui/schedule_navigation_entry.dart
index 95289ce0..1c0fa0db 100644
--- a/lib/schedule/ui/schedule_navigation_entry.dart
+++ b/lib/schedule/ui/schedule_navigation_entry.dart
@@ -42,7 +42,7 @@ class ScheduleNavigationEntry extends NavigationEntry {
       PropertyChangeProvider(
         value: _viewModel,
         child: PropertyChangeConsumer(
-            properties: ["didSetupProperly"],
+            properties: const ["didSetupProperly"],
             builder: (BuildContext _, ScheduleViewModel __, Set<Object> ___) =>
                 _viewModel.didSetupProperly
                     ? Container()
diff --git a/lib/schedule/ui/viewmodels/weekly_schedule_view_model.dart b/lib/schedule/ui/viewmodels/weekly_schedule_view_model.dart
index 74b69f00..8d3e278d 100644
--- a/lib/schedule/ui/viewmodels/weekly_schedule_view_model.dart
+++ b/lib/schedule/ui/viewmodels/weekly_schedule_view_model.dart
@@ -36,6 +36,7 @@ class WeeklyScheduleViewModel extends BaseViewModel {
   Timer _updateNowTimer;
 
   final CancelableMutex _updateMutex = CancelableMutex();
+  
   DateTime lastRequestedStart;
   DateTime lastRequestedEnd;
 
@@ -92,7 +93,7 @@ class WeeklyScheduleViewModel extends BaseViewModel {
 
   Future goToToday() async {
     currentDateStart = toStartOfDay(toMonday(DateTime.now()));
-    currentDateEnd = currentDateStart.add(Duration(days: 5));
+    currentDateEnd = currentDateStart.add(const Duration(days: 5));
 
     await updateSchedule(currentDateStart, currentDateEnd);
   }
@@ -166,13 +167,13 @@ class WeeklyScheduleViewModel extends BaseViewModel {
     return null;
   }
 
-  void _cancelErrorInFuture() async {
+  void _cancelErrorInFuture() {
     if (_errorResetTimer != null) {
       _errorResetTimer.cancel();
     }
 
     _errorResetTimer = Timer(
-      Duration(seconds: 5),
+      const Duration(seconds: 5),
       () {
         updateFailed = false;
         notifyListeners("updateFailed");
@@ -182,7 +183,7 @@ class WeeklyScheduleViewModel extends BaseViewModel {
 
   void ensureUpdateNowTimerRunning() {
     if (_updateNowTimer == null || !_updateNowTimer.isActive) {
-      _updateNowTimer = Timer.periodic(Duration(minutes: 1), (_) {
+      _updateNowTimer = Timer.periodic(const Duration(minutes: 1), (_) {
         notifyListeners("now");
       });
     }
diff --git a/lib/schedule/ui/weeklyschedule/schedule_entry_detail_bottom_sheet.dart b/lib/schedule/ui/weeklyschedule/schedule_entry_detail_bottom_sheet.dart
index 5a760d91..8847e812 100644
--- a/lib/schedule/ui/weeklyschedule/schedule_entry_detail_bottom_sheet.dart
+++ b/lib/schedule/ui/weeklyschedule/schedule_entry_detail_bottom_sheet.dart
@@ -36,10 +36,9 @@ class ScheduleEntryDetailBottomSheet extends StatelessWidget {
                 child: Container(
                   height: 8,
                   width: 30,
-                  decoration: new BoxDecoration(
+                  decoration: BoxDecoration(
                       color: colorSeparator(),
-                      borderRadius:
-                          new BorderRadius.all(const Radius.circular(4))),
+                      borderRadius: const BorderRadius.all(Radius.circular(4))),
                   child: null,
                 ),
               ),
diff --git a/lib/schedule/ui/weeklyschedule/weekly_schedule_page.dart b/lib/schedule/ui/weeklyschedule/weekly_schedule_page.dart
index e9712bbf..fcd6fe24 100644
--- a/lib/schedule/ui/weeklyschedule/weekly_schedule_page.dart
+++ b/lib/schedule/ui/weeklyschedule/weekly_schedule_page.dart
@@ -45,7 +45,7 @@ class _WeeklySchedulePageState extends State<WeeklySchedulePage> {
       builder: (context) => ScheduleEntryDetailBottomSheet(
         scheduleEntry: entry,
       ),
-      shape: RoundedRectangleBorder(
+      shape: const RoundedRectangleBorder(
         borderRadius: BorderRadius.vertical(top: Radius.circular(12.0)),
       ),
     );
@@ -81,12 +81,12 @@ class _WeeklySchedulePageState extends State<WeeklySchedulePage> {
                       Padding(
                         padding: const EdgeInsets.all(8.0),
                         child: PropertyChangeConsumer(
-                          properties: ["weekSchedule", "now"],
+                          properties: const ["weekSchedule", "now"],
                           builder: (BuildContext context,
                               WeeklyScheduleViewModel model, Set properties) {
                             return PageTransitionSwitcher(
                               reverse: !model.didUpdateScheduleIntoFuture,
-                              duration: Duration(milliseconds: 300),
+                              duration: const Duration(milliseconds: 300),
                               transitionBuilder: (Widget child,
                                       Animation<double> animation,
                                       Animation<double> secondaryAnimation) =>
@@ -118,11 +118,11 @@ class _WeeklySchedulePageState extends State<WeeklySchedulePage> {
                         ),
                       ),
                       PropertyChangeConsumer(
-                        properties: ["isUpdating"],
+                        properties: const ["isUpdating"],
                         builder: (BuildContext context,
                             WeeklyScheduleViewModel model, Set properties) {
                           return model.isUpdating
-                              ? LinearProgressIndicator()
+                              ? const LinearProgressIndicator()
                               : Container();
                         },
                       ),
@@ -160,7 +160,7 @@ class _WeeklySchedulePageState extends State<WeeklySchedulePage> {
 
   Widget buildErrorDisplay(BuildContext context) {
     return PropertyChangeConsumer(
-      properties: [
+      properties: const [
         "updateFailed",
       ],
       builder: (BuildContext context, WeeklyScheduleViewModel model,
diff --git a/lib/schedule/ui/weeklyschedule/widgets/schedule_entry_widget.dart b/lib/schedule/ui/weeklyschedule/widgets/schedule_entry_widget.dart
index 2e1a9d59..55bbc649 100644
--- a/lib/schedule/ui/weeklyschedule/widgets/schedule_entry_widget.dart
+++ b/lib/schedule/ui/weeklyschedule/widgets/schedule_entry_widget.dart
@@ -23,7 +23,7 @@ class ScheduleEntryWidget extends StatelessWidget {
     return Card(
       color: color,
       elevation: 5,
-      margin: EdgeInsets.fromLTRB(2, 0, 2, 0),
+      margin: const EdgeInsets.fromLTRB(2, 0, 2, 0),
       child: InkWell(
         onTap: () {
           if (onScheduleEntryTap != null) onScheduleEntryTap(scheduleEntry);
diff --git a/lib/schedule/ui/weeklyschedule/widgets/schedule_widget.dart b/lib/schedule/ui/weeklyschedule/widgets/schedule_widget.dart
index 66b62a15..b39a4691 100644
--- a/lib/schedule/ui/weeklyschedule/widgets/schedule_widget.dart
+++ b/lib/schedule/ui/weeklyschedule/widgets/schedule_widget.dart
@@ -120,7 +120,7 @@ class ScheduleWidget extends StatelessWidget {
     double hourHeight,
     double minuteHeight,
   ) {
-    var labelWidgets = List<Widget>();
+    var labelWidgets = <Widget>[];
 
     for (var i = displayStartHour; i < displayEndHour; i++) {
       var hourLabelText = i.toString() + ":00";
@@ -177,9 +177,9 @@ class ScheduleWidget extends StatelessWidget {
   List<Widget> buildEntryWidgets(
       double hourHeight, double minuteHeight, double width, int columns) {
     if (schedule == null) return <Widget>[];
-    if (schedule.entries.length == 0) return <Widget>[];
+    if (schedule.entries.isEmpty) return <Widget>[];
 
-    var entryWidgets = List<Widget>();
+    var entryWidgets = <Widget>[];
 
     var columnWidth = width / columns;
 
diff --git a/lib/schedule/ui/widgets/enter_rapla_url_dialog.dart b/lib/schedule/ui/widgets/enter_rapla_url_dialog.dart
index 18ac5f06..7dc21ef7 100644
--- a/lib/schedule/ui/widgets/enter_rapla_url_dialog.dart
+++ b/lib/schedule/ui/widgets/enter_rapla_url_dialog.dart
@@ -11,8 +11,8 @@ class EnterRaplaUrlDialog {
   final ScheduleSourceSetup _scheduleSource;
 
   final TextEditingController _urlTextController = TextEditingController();
-  ValueNotifier<bool> _hasUrlError = ValueNotifier<bool>(false);
-  ValueNotifier<String> _url = ValueNotifier<String>("");
+  final ValueNotifier<bool> _hasUrlError = ValueNotifier<bool>(false);
+  final ValueNotifier<String> _url = ValueNotifier<String>("");
 
   EnterRaplaUrlDialog(this._preferencesProvider, this._scheduleSource) {
     _loadUrl();
diff --git a/lib/schedule/ui/widgets/schedule_empty_state.dart b/lib/schedule/ui/widgets/schedule_empty_state.dart
index 1b03ad34..01c96972 100644
--- a/lib/schedule/ui/widgets/schedule_empty_state.dart
+++ b/lib/schedule/ui/widgets/schedule_empty_state.dart
@@ -21,7 +21,7 @@ class ScheduleEmptyState extends StatelessWidget {
               boxShadow: [
                 BoxShadow(
                   color: Theme.of(context).dividerColor,
-                  offset: Offset(0.0, 1.0),
+                  offset: const Offset(0.0, 1.0),
                   blurRadius: 1.0,
                 ),
               ],
diff --git a/lib/ui/main_page.dart b/lib/ui/main_page.dart
index db337fc0..1df6468a 100644
--- a/lib/ui/main_page.dart
+++ b/lib/ui/main_page.dart
@@ -23,7 +23,7 @@ class MainPage extends StatefulWidget {
 class _MainPageState extends State<MainPage> with NavigatorObserver {
   bool _rateDialogShown = false;
 
-  ValueNotifier<int> _currentEntryIndex = ValueNotifier<int>(0);
+  final ValueNotifier<int> _currentEntryIndex = ValueNotifier<int>(0);
 
   NavigationEntry get currentEntry =>
       navigationEntries[_currentEntryIndex.value];
diff --git a/lib/ui/navigation/router.dart b/lib/ui/navigation/router.dart
index 2bb8e124..72c5fe58 100644
--- a/lib/ui/navigation/router.dart
+++ b/lib/ui/navigation/router.dart
@@ -18,7 +18,7 @@ final List<NavigationEntry> navigationEntries = [
 Route<dynamic> generateDrawerRoute(RouteSettings settings) {
   print("=== === === === === === Navigating to: ${settings.name}");
 
-  var widget;
+  WidgetBuilder widget;
 
   for (var route in navigationEntries) {
     if (route.route == settings.name) {
@@ -34,17 +34,17 @@ Route<dynamic> generateDrawerRoute(RouteSettings settings) {
 
   return PageRouteBuilder(
     settings: settings,
-    transitionDuration: Duration(milliseconds: 200),
+    transitionDuration: const Duration(milliseconds: 200),
     pageBuilder: (context, animation, secondaryAnimation) => widget(context),
     transitionsBuilder: (context, animation, secondaryAnimation, child) {
-      var offsetBegin = Offset(0.0, 0.005);
-      var offsetEnd = Offset.zero;
-      var offsetTween = Tween(begin: offsetBegin, end: offsetEnd)
+      const offsetBegin = Offset(0.0, 0.005);
+      final offsetEnd = Offset.zero;
+      final offsetTween = Tween(begin: offsetBegin, end: offsetEnd)
           .chain(CurveTween(curve: Curves.fastOutSlowIn));
 
-      var opacityBegin = 0.0;
-      var opacityEnd = 1.0;
-      var opacityTween = Tween(begin: opacityBegin, end: opacityEnd)
+      const opacityBegin = 0.0;
+      const opacityEnd = 1.0;
+      final opacityTween = Tween(begin: opacityBegin, end: opacityEnd)
           .chain(CurveTween(curve: Curves.fastOutSlowIn));
 
       return SlideTransition(
@@ -63,11 +63,11 @@ Route<dynamic> generateDrawerRoute(RouteSettings settings) {
 
 Route<dynamic> generateRoute(RouteSettings settings) {
   print("=== === === === === === Navigating to: ${settings.name}");
-  var target;
+  Widget target;
 
   switch (settings.name) {
     case "onboarding":
-      target = OnboardingPage();
+      target = const OnboardingPage();
       break;
     case "main":
       target = MainPage();
diff --git a/lib/ui/onboarding/onboarding_page.dart b/lib/ui/onboarding/onboarding_page.dart
index 5984f72b..56d3cf7f 100644
--- a/lib/ui/onboarding/onboarding_page.dart
+++ b/lib/ui/onboarding/onboarding_page.dart
@@ -29,7 +29,7 @@ class _OnboardingPageState extends State<OnboardingPage>
   void initState() {
     super.initState();
 
-    viewModel = new OnboardingViewModel(
+    viewModel = OnboardingViewModel(
       KiwiContainer().resolve(),
       KiwiContainer().resolve(),
     );
@@ -39,7 +39,7 @@ class _OnboardingPageState extends State<OnboardingPage>
         await _controller.animateTo(
             viewModel.currentStep / viewModel.onboardingSteps,
             curve: Curves.ease,
-            duration: Duration(milliseconds: 300));
+            duration: const Duration(milliseconds: 300));
       },
       ["currentStep"],
     );
@@ -54,7 +54,7 @@ class _OnboardingPageState extends State<OnboardingPage>
       child: Scaffold(
         body: Stack(
           children: <Widget>[
-            buildContent(),
+            _buildContent(),
             OnboardingPageBackground(controller: _controller.view),
           ],
         ),
@@ -63,13 +63,13 @@ class _OnboardingPageState extends State<OnboardingPage>
     );
   }
 
-  Widget buildContent() {
+  Widget _buildContent() {
     return GestureDetector(
       onPanEnd: (details) {
         if (details.velocity.pixelsPerSecond.dx > 10) {
-          navigateBack(context);
+          _navigateBack(context);
         } else if (details.velocity.pixelsPerSecond.dx < -10) {
-          navigateNext(context);
+          _navigateNext(context);
         }
       },
       behavior: HitTestBehavior.translucent,
@@ -81,13 +81,13 @@ class _OnboardingPageState extends State<OnboardingPage>
               mainAxisSize: MainAxisSize.max,
               mainAxisAlignment: MainAxisAlignment.spaceBetween,
               children: <Widget>[
-                buildActiveOnboardingPage(model),
+                _buildActiveOnboardingPage(model),
                 OnboardingButtonBar(
                   onPrevious: () {
-                    navigateBack(context);
+                    _navigateBack(context);
                   },
                   onNext: () {
-                    navigateNext(context);
+                    _navigateNext(context);
                   },
                   viewModel: viewModel,
                 ),
@@ -99,7 +99,7 @@ class _OnboardingPageState extends State<OnboardingPage>
     );
   }
 
-  Widget buildActiveOnboardingPage(OnboardingViewModel model) {
+  Widget _buildActiveOnboardingPage(OnboardingViewModel model) {
     var contentWidgets = {
       OnboardingSteps.Start: () => SelectAppFeaturesWidget(
             viewModel: viewModel,
@@ -124,7 +124,7 @@ class _OnboardingPageState extends State<OnboardingPage>
     return IntrinsicHeight(
       child: PageTransitionSwitcher(
         reverse: !model.didStepForward,
-        duration: Duration(milliseconds: 300),
+        duration: const Duration(milliseconds: 300),
         transitionBuilder: (
           Widget child,
           Animation<double> animation,
@@ -141,7 +141,7 @@ class _OnboardingPageState extends State<OnboardingPage>
     );
   }
 
-  void navigateNext(BuildContext context) {
+  void _navigateNext(BuildContext context) {
     if (viewModel.currentStep == viewModel.onboardingSteps - 1) {
       viewModel.save();
 
@@ -156,7 +156,7 @@ class _OnboardingPageState extends State<OnboardingPage>
     }
   }
 
-  void navigateBack(BuildContext context) {
+  void _navigateBack(BuildContext context) {
     viewModel.previousPage();
   }
 }
diff --git a/lib/ui/onboarding/viewmodels/onboarding_rapla_view_model.dart b/lib/ui/onboarding/viewmodels/onboarding_rapla_view_model.dart
index c1d47383..887fce82 100644
--- a/lib/ui/onboarding/viewmodels/onboarding_rapla_view_model.dart
+++ b/lib/ui/onboarding/viewmodels/onboarding_rapla_view_model.dart
@@ -23,7 +23,7 @@ class OnboardingRaplaViewModel extends OnboardingViewModelBase {
 
   void _validateUrl() {
     try {
-      new RaplaScheduleSource().validateEndpointUrl(_raplaUrl);
+      RaplaScheduleSource().validateEndpointUrl(_raplaUrl);
       urlHasError = false;
     } catch (e) {
       urlHasError = true;
diff --git a/lib/ui/onboarding/viewmodels/onboarding_view_model.dart b/lib/ui/onboarding/viewmodels/onboarding_view_model.dart
index 3db9ee7d..3d7c057a 100644
--- a/lib/ui/onboarding/viewmodels/onboarding_view_model.dart
+++ b/lib/ui/onboarding/viewmodels/onboarding_view_model.dart
@@ -21,7 +21,7 @@ class OnboardingViewModel extends BaseViewModel {
     OnboardingSteps.Dualis: true,
   };
 
-  Map<OnboardingSteps, OnboardingViewModelBase> _viewModels = {};
+  final Map<OnboardingSteps, OnboardingViewModelBase> _viewModels = {};
   OnboardingViewModelBase get currentViewModel => _viewModels[_currentPage];
 
   bool get useRapla => usedAppFeatures[OnboardingSteps.Rapla];
@@ -85,7 +85,7 @@ class OnboardingViewModel extends BaseViewModel {
   }
 
   void _setCurrentPage() {
-    var activeFeatures = <OnboardingSteps>[];
+    final activeFeatures = <OnboardingSteps>[];
 
     for (var feature in OnboardingSteps.values) {
       if (usedAppFeatures[feature]) {
diff --git a/lib/ui/onboarding/widgets/dots_indicator.dart b/lib/ui/onboarding/widgets/dots_indicator.dart
index e195e028..76d1b35c 100644
--- a/lib/ui/onboarding/widgets/dots_indicator.dart
+++ b/lib/ui/onboarding/widgets/dots_indicator.dart
@@ -20,7 +20,7 @@ class DotsIndicator extends StatelessWidget {
           child: Container(
             width: 7.0,
             height: 7.0,
-            decoration: new BoxDecoration(
+            decoration: BoxDecoration(
               shape: BoxShape.circle,
               color: i == currentStep
                   ? Theme.of(context).accentColor
diff --git a/lib/ui/onboarding/widgets/dualis_login_page.dart b/lib/ui/onboarding/widgets/dualis_login_page.dart
index f4651745..7c840e41 100644
--- a/lib/ui/onboarding/widgets/dualis_login_page.dart
+++ b/lib/ui/onboarding/widgets/dualis_login_page.dart
@@ -6,6 +6,10 @@ import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:property_change_notifier/property_change_notifier.dart';
 
+///
+/// Widget which provides a username and password text field to input login
+/// credentials.
+///
 class DualisLoginCredentialsPage extends StatefulWidget {
   @override
   _DualisLoginCredentialsPageState createState() =>
@@ -14,8 +18,10 @@ class DualisLoginCredentialsPage extends StatefulWidget {
 
 class _DualisLoginCredentialsPageState
     extends State<DualisLoginCredentialsPage> {
-  TextEditingController _usernameEditingController = TextEditingController();
-  TextEditingController _passwordEditingController = TextEditingController();
+  final TextEditingController _usernameEditingController =
+      TextEditingController();
+  final TextEditingController _passwordEditingController =
+      TextEditingController();
 
   @override
   Widget build(BuildContext context) {
@@ -73,7 +79,7 @@ class _DualisLoginCredentialsPageState
                     : Container(),
               ),
               viewModel.isLoading
-                  ? SizedBox(
+                  ? const SizedBox(
                       width: 16,
                       height: 16,
                       child: CircularProgressIndicator(
@@ -81,7 +87,7 @@ class _DualisLoginCredentialsPageState
                       ),
                     )
                   : viewModel.loginSuccess
-                      ? Icon(
+                      ? const Icon(
                           Icons.check,
                           color: Colors.green,
                         )
@@ -121,8 +127,8 @@ class _DualisLoginCredentialsPageState
           ),
         ),
       ),
-      Padding(
-        padding: const EdgeInsets.fromLTRB(0, 16, 0, 16),
+      const Padding(
+        padding: EdgeInsets.fromLTRB(0, 16, 0, 16),
         child: Divider(),
       ),
       Padding(
diff --git a/lib/ui/onboarding/widgets/onboarding_button_bar.dart b/lib/ui/onboarding/widgets/onboarding_button_bar.dart
index 14acb6cb..c2d06c3b 100644
--- a/lib/ui/onboarding/widgets/onboarding_button_bar.dart
+++ b/lib/ui/onboarding/widgets/onboarding_button_bar.dart
@@ -47,7 +47,7 @@ class OnboardingButtonBar extends StatelessWidget {
     bool isFirstPage = viewModel.currentStep == 0;
 
     return AnimatedSwitcher(
-      duration: Duration(milliseconds: 100),
+      duration: const Duration(milliseconds: 100),
       child: isFirstPage
           ? Container()
           : FlatButton.icon(
@@ -62,7 +62,7 @@ class OnboardingButtonBar extends StatelessWidget {
   Widget _buildNextButton(BuildContext context) {
     bool isLastPage = viewModel.currentStep == viewModel.onboardingSteps - 1;
 
-    var buttonText;
+    String buttonText;
     var buttonColor = Theme.of(context).accentColor;
 
     if (isLastPage) {
@@ -76,7 +76,7 @@ class OnboardingButtonBar extends StatelessWidget {
     }
 
     return AnimatedSwitcher(
-      duration: Duration(milliseconds: 100),
+      duration: const Duration(milliseconds: 100),
       child: FlatButton.icon(
         key: ValueKey(buttonText),
         onPressed: onNext,
diff --git a/lib/ui/onboarding/widgets/onboarding_page_background.dart b/lib/ui/onboarding/widgets/onboarding_page_background.dart
index fa36e3db..b2fdc4f3 100644
--- a/lib/ui/onboarding/widgets/onboarding_page_background.dart
+++ b/lib/ui/onboarding/widgets/onboarding_page_background.dart
@@ -27,7 +27,7 @@ class OnboardingPageBackground extends StatelessWidget {
         ).animate(
           CurvedAnimation(
             parent: controller,
-            curve: Interval(
+            curve: const Interval(
               0.0,
               1,
               curve: Curves.linear,
@@ -40,7 +40,7 @@ class OnboardingPageBackground extends StatelessWidget {
         ).animate(
           CurvedAnimation(
             parent: controller,
-            curve: Interval(
+            curve: const Interval(
               0.0,
               1,
               curve: Curves.linear,
@@ -53,7 +53,7 @@ class OnboardingPageBackground extends StatelessWidget {
         ).animate(
           CurvedAnimation(
             parent: controller,
-            curve: Interval(
+            curve: const Interval(
               0.0,
               1,
               curve: Curves.linear,
@@ -66,7 +66,7 @@ class OnboardingPageBackground extends StatelessWidget {
         ).animate(
           CurvedAnimation(
             parent: controller,
-            curve: Interval(
+            curve: const Interval(
               0.0,
               1,
               curve: Curves.linear,
@@ -85,7 +85,7 @@ class OnboardingPageBackground extends StatelessWidget {
               height: 500,
               color: colorOnboardingDecorationForeground(context),
             ),
-            offset: Offset(20, -450),
+            offset: const Offset(20, -450),
           ),
           angle: toRadian(angleTopForeground.value),
         ),
@@ -96,7 +96,7 @@ class OnboardingPageBackground extends StatelessWidget {
               height: 500,
               color: colorOnboardingDecorationBackground(context),
             ),
-            offset: Offset(20, -480),
+            offset: const Offset(20, -480),
           ),
           angle: toRadian(angleTopBackground.value),
         ),
diff --git a/lib/ui/onboarding/widgets/rapla_url_page.dart b/lib/ui/onboarding/widgets/rapla_url_page.dart
index 67e817e5..2a6c7419 100644
--- a/lib/ui/onboarding/widgets/rapla_url_page.dart
+++ b/lib/ui/onboarding/widgets/rapla_url_page.dart
@@ -11,7 +11,7 @@ class RaplaUrlPage extends StatefulWidget {
 }
 
 class _RaplaUrlPageState extends State<RaplaUrlPage> {
-  final TextEditingController _urlTextController = new TextEditingController();
+  final TextEditingController _urlTextController = TextEditingController();
 
   @override
   Widget build(BuildContext context) {
@@ -28,8 +28,8 @@ class _RaplaUrlPageState extends State<RaplaUrlPage> {
             ),
           ),
         ),
-        Padding(
-          padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
+        const Padding(
+          padding: EdgeInsets.fromLTRB(0, 16, 0, 0),
           child: Divider(),
         ),
         Text(
diff --git a/lib/ui/onboarding/widgets/select_app_features.dart b/lib/ui/onboarding/widgets/select_app_features.dart
index 7dd87e58..7623ef1f 100644
--- a/lib/ui/onboarding/widgets/select_app_features.dart
+++ b/lib/ui/onboarding/widgets/select_app_features.dart
@@ -24,8 +24,8 @@ class SelectAppFeaturesWidget extends StatelessWidget {
             ),
           ),
         ),
-        Padding(
-          padding: const EdgeInsets.fromLTRB(0, 16, 0, 0),
+        const Padding(
+          padding: EdgeInsets.fromLTRB(0, 16, 0, 0),
           child: Divider(),
         ),
         PropertyChangeConsumer(
diff --git a/lib/ui/pager_widget.dart b/lib/ui/pager_widget.dart
index 82cb3a29..5d74cf33 100644
--- a/lib/ui/pager_widget.dart
+++ b/lib/ui/pager_widget.dart
@@ -45,7 +45,7 @@ class _PagerWidgetState extends State<PagerWidget> {
   Widget build(BuildContext context) {
     return Scaffold(
       body: AnimatedSwitcher(
-        duration: Duration(milliseconds: 300),
+        duration: const Duration(milliseconds: 300),
         child: Column(
           key: ValueKey(_currentPage),
           children: <Widget>[
diff --git a/lib/ui/root_page.dart b/lib/ui/root_page.dart
index 0e8ad1d6..cdb3b479 100644
--- a/lib/ui/root_page.dart
+++ b/lib/ui/root_page.dart
@@ -36,7 +36,7 @@ class _RootPageState extends State<RootPage> {
   Widget build(BuildContext context) {
     return PropertyChangeProvider(
       child: PropertyChangeConsumer(
-        properties: ["isDarkMode", "isOnboarding"],
+        properties: const ["isDarkMode", "isOnboarding"],
         builder: (BuildContext context, RootViewModel model, Set properties) =>
             MaterialApp(
           theme: ColorPalettes.buildTheme(model.isDarkMode),
@@ -49,9 +49,9 @@ class _RootPageState extends State<RootPage> {
             GlobalCupertinoLocalizations.delegate,
             DefaultCupertinoLocalizations.delegate,
           ],
-          supportedLocales: [
-            const Locale('en'),
-            const Locale('de'),
+          supportedLocales: const [
+            Locale('en'),
+            Locale('de'),
           ],
           onGenerateRoute: generateRoute,
         ),
diff --git a/lib/ui/settings/settings_page.dart b/lib/ui/settings/settings_page.dart
index 5d68dad2..a8f3a874 100644
--- a/lib/ui/settings/settings_page.dart
+++ b/lib/ui/settings/settings_page.dart
@@ -12,6 +12,10 @@ import 'package:property_change_notifier/property_change_notifier.dart';
 import 'package:url_launcher/url_launcher.dart';
 import 'package:kiwi/kiwi.dart';
 
+///
+/// Widget for the application settings route. Provides access to many settings
+/// of the app
+///
 class SettingsPage extends StatefulWidget {
   @override
   _SettingsPageState createState() => _SettingsPageState();
@@ -20,7 +24,8 @@ class SettingsPage extends StatefulWidget {
 class _SettingsPageState extends State<SettingsPage> {
   final SettingsViewModel settingsViewModel = SettingsViewModel(
     KiwiContainer().resolve(),
-    KiwiContainer().resolve<TaskCallback>(NextDayInformationNotification.name),
+    KiwiContainer().resolve<TaskCallback>(NextDayInformationNotification.name)
+        as NextDayInformationNotification,
   );
 
   @override
@@ -86,7 +91,7 @@ class _SettingsPageState extends State<SettingsPage> {
           launch(ApplicationSourceCodeUrl);
         },
       ),
-      Divider(),
+      const Divider(),
     ];
   }
 
@@ -102,7 +107,7 @@ class _SettingsPageState extends State<SettingsPage> {
           ).show(context);
         },
       ),
-      Divider(),
+      const Divider(),
     ];
   }
 
@@ -112,7 +117,7 @@ class _SettingsPageState extends State<SettingsPage> {
       return [
         TitleListTile(title: L.of(context).settingsNotificationsTitle),
         PropertyChangeConsumer(
-          properties: [
+          properties: const [
             "notifyAboutNextDay",
           ],
           builder:
@@ -125,7 +130,7 @@ class _SettingsPageState extends State<SettingsPage> {
           },
         ),
         PropertyChangeConsumer(
-          properties: [
+          properties: const [
             "notifyAboutScheduleChanges",
           ],
           builder:
@@ -137,7 +142,7 @@ class _SettingsPageState extends State<SettingsPage> {
             );
           },
         ),
-        Divider(),
+        const Divider(),
       ];
     } else {
       return [];
@@ -148,7 +153,7 @@ class _SettingsPageState extends State<SettingsPage> {
     return [
       TitleListTile(title: L.of(context).settingsDesign),
       PropertyChangeConsumer(
-        properties: [
+        properties: const [
           "isDarkMode",
         ],
         builder: (BuildContext context, RootViewModel model, Set properties) {
@@ -159,7 +164,7 @@ class _SettingsPageState extends State<SettingsPage> {
           );
         },
       ),
-      Divider(),
+      const Divider(),
     ];
   }
 }
diff --git a/lib/ui/settings/viewmodels/settings_view_model.dart b/lib/ui/settings/viewmodels/settings_view_model.dart
index 42ee2c24..f92f942c 100644
--- a/lib/ui/settings/viewmodels/settings_view_model.dart
+++ b/lib/ui/settings/viewmodels/settings_view_model.dart
@@ -2,20 +2,24 @@ import 'package:dhbwstudentapp/common/data/preferences/preferences_provider.dart
 import 'package:dhbwstudentapp/common/ui/viewmodels/base_view_model.dart';
 import 'package:dhbwstudentapp/schedule/ui/notification/next_day_information_notification.dart';
 
+///
+/// The view model for the settings page.
+///
 class SettingsViewModel extends BaseViewModel {
+  final PreferencesProvider _preferencesProvider;
+  final NextDayInformationNotification _nextDayInformationNotification;
+
   bool _notifyAboutNextDay = false;
   bool get notifyAboutNextDay => _notifyAboutNextDay;
 
   bool _notifyAboutScheduleChanges = false;
   bool get notifyAboutScheduleChanges => _notifyAboutScheduleChanges;
 
-  final PreferencesProvider _preferencesProvider;
-
-  final NextDayInformationNotification _nextDayInformationNotification;
-
   SettingsViewModel(
-      this._preferencesProvider, this._nextDayInformationNotification) {
-    loadPreferences();
+    this._preferencesProvider,
+    this._nextDayInformationNotification,
+  ) {
+    _loadPreferences();
   }
 
   Future<void> setNotifyAboutScheduleChanges(bool value) async {
@@ -39,7 +43,7 @@ class SettingsViewModel extends BaseViewModel {
       await _nextDayInformationNotification.cancel();
   }
 
-  Future<void> loadPreferences() async {
+  Future<void> _loadPreferences() async {
     _notifyAboutNextDay = await _preferencesProvider.getNotifyAboutNextDay();
     _notifyAboutScheduleChanges =
         await _preferencesProvider.getNotifyAboutScheduleChanges();
diff --git a/test/date_management/service/parsing/all_dates_extract_test.dart b/test/date_management/service/parsing/all_dates_extract_test.dart
index c61bffbd..feda9186 100644
--- a/test/date_management/service/parsing/all_dates_extract_test.dart
+++ b/test/date_management/service/parsing/all_dates_extract_test.dart
@@ -4,7 +4,7 @@ import 'package:dhbwstudentapp/date_management/service/parsing/all_dates_extract
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var allDatesPage = await new File(Directory.current.absolute.path +
+  var allDatesPage = await File(Directory.current.absolute.path +
           '/test/date_management/service/parsing/html_resources/all_dates.html')
       .readAsString();
 
diff --git a/test/dualis/service/parsing/all_modules_extract_test.dart b/test/dualis/service/parsing/all_modules_extract_test.dart
index fe0aa60e..faf73b78 100644
--- a/test/dualis/service/parsing/all_modules_extract_test.dart
+++ b/test/dualis/service/parsing/all_modules_extract_test.dart
@@ -6,7 +6,7 @@ import 'package:dhbwstudentapp/dualis/service/parsing/parsing_utils.dart';
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var studentResultsPage = await new File(Directory.current.absolute.path +
+  var studentResultsPage = await File(Directory.current.absolute.path +
           '/test/dualis/service/parsing/html_resources/student_results.html')
       .readAsString();
 
diff --git a/test/dualis/service/parsing/exams_from_module_details_extract_test.dart b/test/dualis/service/parsing/exams_from_module_details_extract_test.dart
index 2098f521..55e997c9 100644
--- a/test/dualis/service/parsing/exams_from_module_details_extract_test.dart
+++ b/test/dualis/service/parsing/exams_from_module_details_extract_test.dart
@@ -5,7 +5,7 @@ import 'package:dhbwstudentapp/dualis/service/parsing/parsing_utils.dart';
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var moduleDetailsPage = await new File(Directory.current.absolute.path +
+  var moduleDetailsPage = await File(Directory.current.absolute.path +
           '/test/dualis/service/parsing/html_resources/module_details.html')
       .readAsString();
 
diff --git a/test/dualis/service/parsing/modules_from_course_result_page_extract_test.dart b/test/dualis/service/parsing/modules_from_course_result_page_extract_test.dart
index b54d1fca..28bcc7d9 100644
--- a/test/dualis/service/parsing/modules_from_course_result_page_extract_test.dart
+++ b/test/dualis/service/parsing/modules_from_course_result_page_extract_test.dart
@@ -5,7 +5,7 @@ import 'package:dhbwstudentapp/dualis/service/parsing/parsing_utils.dart';
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var courseResultsPage = await new File(Directory.current.absolute.path +
+  var courseResultsPage = await File(Directory.current.absolute.path +
           '/test/dualis/service/parsing/html_resources/course_results.html')
       .readAsString();
 
diff --git a/test/dualis/service/parsing/semesters_from_course_result_page_extract_test.dart b/test/dualis/service/parsing/semesters_from_course_result_page_extract_test.dart
index 0815c692..261c3692 100644
--- a/test/dualis/service/parsing/semesters_from_course_result_page_extract_test.dart
+++ b/test/dualis/service/parsing/semesters_from_course_result_page_extract_test.dart
@@ -5,7 +5,7 @@ import 'package:dhbwstudentapp/dualis/service/parsing/semesters_from_course_resu
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var courseResultsPage = await new File(Directory.current.absolute.path +
+  var courseResultsPage = await File(Directory.current.absolute.path +
           '/test/dualis/service/parsing/html_resources/course_results.html')
       .readAsString();
 
diff --git a/test/dualis/service/parsing/study_grades_from_student_results_page_extract_test.dart b/test/dualis/service/parsing/study_grades_from_student_results_page_extract_test.dart
index 1f372e78..660e0747 100644
--- a/test/dualis/service/parsing/study_grades_from_student_results_page_extract_test.dart
+++ b/test/dualis/service/parsing/study_grades_from_student_results_page_extract_test.dart
@@ -5,7 +5,7 @@ import 'package:dhbwstudentapp/dualis/service/parsing/study_grades_from_student_
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var studentResultsPage = await new File(Directory.current.absolute.path +
+  var studentResultsPage = await File(Directory.current.absolute.path +
           '/test/dualis/service/parsing/html_resources/student_results.html')
       .readAsString();
 
diff --git a/test/dualis/service/parsing/urls_from_main_page_extract_test.dart b/test/dualis/service/parsing/urls_from_main_page_extract_test.dart
index 10d1347b..fef8e0d8 100644
--- a/test/dualis/service/parsing/urls_from_main_page_extract_test.dart
+++ b/test/dualis/service/parsing/urls_from_main_page_extract_test.dart
@@ -5,7 +5,7 @@ import 'package:dhbwstudentapp/dualis/service/parsing/urls_from_main_page_extrac
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var mainPage = await new File(Directory.current.absolute.path +
+  var mainPage = await File(Directory.current.absolute.path +
           '/test/dualis/service/parsing/html_resources/main_page.html')
       .readAsString();
 
diff --git a/test/schedule/business/schedule_diff_calculator_test.dart b/test/schedule/business/schedule_diff_calculator_test.dart
index dcb031cd..89b834d7 100644
--- a/test/schedule/business/schedule_diff_calculator_test.dart
+++ b/test/schedule/business/schedule_diff_calculator_test.dart
@@ -18,15 +18,15 @@ void main() {
   });
 
   test('Diff detect removed entry', () async {
-    var calculator = ScheduleDiffCalculator();
+    final calculator = ScheduleDiffCalculator();
 
-    var oldSchedule = generateSchedule();
-    var newSchedule = generateSchedule();
+    final oldSchedule = generateSchedule();
+    final newSchedule = generateSchedule();
 
-    var removedEntry = oldSchedule.entries[0];
+    final removedEntry = oldSchedule.entries[0];
     newSchedule.entries.removeAt(0);
 
-    var diff = calculator.calculateDiff(oldSchedule, newSchedule);
+    final diff = calculator.calculateDiff(oldSchedule, newSchedule);
 
     expect(diff.removedEntries.length, 1);
     expect(diff.removedEntries[0], removedEntry);
@@ -72,7 +72,7 @@ void main() {
       title: newSchedule.entries[0].title,
       professor: newSchedule.entries[0].professor,
       details: newSchedule.entries[0].details,
-      start: newSchedule.entries[0].start.add(Duration(minutes: 15)),
+      start: newSchedule.entries[0].start.add(const Duration(minutes: 15)),
       end: newSchedule.entries[0].end,
     );
     newSchedule.entries[0] = updatedEntry;
@@ -99,7 +99,7 @@ void main() {
       title: newSchedule.entries[0].title,
       professor: newSchedule.entries[0].professor,
       details: newSchedule.entries[0].details,
-      start: newSchedule.entries[0].start.add(Duration(minutes: 15)),
+      start: newSchedule.entries[0].start.add(const Duration(minutes: 15)),
       end: newSchedule.entries[0].end,
     );
     newSchedule.entries[0] = updatedEntry;
@@ -127,7 +127,7 @@ void main() {
       title: newSchedule.entries[2].title,
       professor: newSchedule.entries[2].professor,
       details: newSchedule.entries[2].details,
-      start: newSchedule.entries[2].start.add(Duration(minutes: 15)),
+      start: newSchedule.entries[2].start.add(const Duration(minutes: 15)),
       end: newSchedule.entries[2].end,
     );
     newSchedule.entries[2] = updatedEntry1;
@@ -138,7 +138,7 @@ void main() {
       title: newSchedule.entries[3].title,
       professor: newSchedule.entries[3].professor,
       details: newSchedule.entries[3].details,
-      start: newSchedule.entries[3].start.add(Duration(minutes: 15)),
+      start: newSchedule.entries[3].start.add(const Duration(minutes: 15)),
       end: newSchedule.entries[3].end,
     );
     newSchedule.entries[3] = updatedEntry2;
diff --git a/test/schedule/service/rapla/rapla_response_parser_test.dart b/test/schedule/service/rapla/rapla_response_parser_test.dart
index 1f05533d..6140197e 100644
--- a/test/schedule/service/rapla/rapla_response_parser_test.dart
+++ b/test/schedule/service/rapla/rapla_response_parser_test.dart
@@ -5,7 +5,7 @@ import 'package:dhbwstudentapp/schedule/service/rapla/rapla_response_parser.dart
 import 'package:test/test.dart';
 
 Future<void> main() async {
-  var raplaPage = await new File(Directory.current.absolute.path +
+  var raplaPage = await File(Directory.current.absolute.path +
           '/test/schedule/service/rapla/html_resources/rapla_response.html')
       .readAsString();