修复中途退出考试报错问题

Quest.py

@@ -63,6 +63,7 @@ class ExamApp:
 
     def init_main_menu(self):
         self.clear_screen()
+        self.is_submitted = True
         tk.Label(self.root, text="选择考试级别").pack(pady=20)
         for level in ['A', 'B', 'C']:
             tk.Button(self.root, text=f"级别 {level}", command=lambda l=level: self.start_exam(l)).pack(pady=10)
@@ -203,6 +204,10 @@ class ExamApp:
             mins, secs = divmod(self.time_left, 60)
             self.timer_score_label.config(text=f"剩余时间：{mins:02}:{secs:02}")
             self.root.after(1000, self.update_timer)
+        elif self.is_submitted:
+            return
+        else:
+            self.submit_exam()
 
     def clear_screen(self):
         for widget in self.root.winfo_children():