Merge pull request #677 from sseu-buhzzi/20260510/fix-missing-sem-start-date

fix: avoid setting `thisSemesterStartDate` when it is missing

Author: w568w

lib/page/subpage_timetable.dart

@@ -683,8 +683,11 @@ class SemesterSelectionButtonState extends State<SemesterSelectionButton> {
     }
     SettingsProvider.getInstance().semesterStartDates =
         semesterBundle.startDates;
-    SettingsProvider.getInstance().thisSemesterStartDate =
-        semesterBundle.startDates.parseStartDate(chosenSemester);
+    semesterBundle.startDates
+        .parseStartDate(chosenSemester)
+        ?.apply(
+          (sd) => SettingsProvider.getInstance().thisSemesterStartDate = sd,
+        );
   }
 
   @override

lib/provider/settings_provider.dart

@@ -179,7 +179,11 @@ class SettingsProvider with ChangeNotifier {
   }
 
   set timetableSemester(String? value) {
-    preferences!.setString(KEY_TIMETABLE_SEMESTER, value!);
+    if (value != null) {
+      preferences!.setString(KEY_TIMETABLE_SEMESTER, value);
+    } else {
+      preferences!.remove(KEY_TIMETABLE_SEMESTER);
+    }
     notifyListeners();
   }
 
@@ -356,7 +360,11 @@ class SettingsProvider with ChangeNotifier {
   }
 
   set thisSemesterStartDate(String? value) {
-    preferences!.setString(KEY_THIS_SEMESTER_START_DATE, value!);
+    if (value != null) {
+      preferences!.setString(KEY_THIS_SEMESTER_START_DATE, value);
+    } else {
+      preferences!.remove(KEY_THIS_SEMESTER_START_DATE);
+    }
     notifyListeners();
   }
 
@@ -369,7 +377,11 @@ class SettingsProvider with ChangeNotifier {
   }
 
   set semesterStartDates(SemesterStartDates? value) {
-    preferences!.setString(KEY_SEMESTER_START_DATES, jsonEncode(value!));
+    if (value != null) {
+      preferences!.setString(KEY_SEMESTER_START_DATES, jsonEncode(value));
+    } else {
+      preferences!.remove(KEY_SEMESTER_START_DATES);
+    }
     notifyListeners();
   }
 

lib/repository/fdu/edu_service_repository.dart

@@ -29,9 +29,6 @@ import 'package:flutter/widgets.dart';
 import 'neo_login_tool.dart';
 
 class EduServiceRepository extends BaseRepositoryWithDio {
-  static const String COURSE_TABLE_URL =
-      'https://fdjwgl.fudan.edu.cn/student/for-std/course-table';
-
   static String getSemesterCourseTableUrl(String semesterId) =>
       'https://fdjwgl.fudan.edu.cn/student/for-std/course-table/semester/$semesterId/print-data';