Django属性错误：'int‘对象没有属性'essay_question’- Django测验应用程序

Question

当我将Django测验应用集成到我的项目中时，我一直收到这个错误，并且不知道如何解决它。我可以创建测验并在列表中查看它们，但是一旦我按下“开始测验”按钮，我就会收到这个错误。我需要在我的项目中进行哪些更改才能解决此问题？

下面是完整的回溯：

Environment:

Request Method: GET
Request URL: http://127.0.0.1:8000/quizzes/testquiz/take/

Django Version: 1.9.1
Python Version: 2.7.10
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'myapp',
 'essay',
 'quiz',
 'multichoice',
 'true_false',
 'bootstrapform']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "/home/john/.virtualenvs/lfs/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  149.                     response = self.process_exception_by_middleware(e, request)

File "/home/john/.virtualenvs/lfs/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  147.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/home/john/.virtualenvs/lfs/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  68.             return self.dispatch(request, *args, **kwargs)

File "/home/john/myapp/quiz/views.py" in dispatch
  148.                                                         self.quiz)

File "/home/john/myapp/quiz/models.py" in user_sitting
  341.             sitting = self.new_sitting(user, quiz)

File "/home/john/myapp/quiz/models.py" in new_sitting
  312.         if len(question_set) == 0:

File "/home/john/.virtualenvs/lfs/local/lib/python2.7/site-packages/django/db/models/query.py" in __len__
  240.         self._fetch_all()

File "/home/john/.virtualenvs/lfs/local/lib/python2.7/site-packages/django/db/models/query.py" in _fetch_all
  1074.             self._result_cache = list(self.iterator())

File "/home/john/.virtualenvs/lfs/local/lib/python2.7/site-packages/model_utils/managers.py" in iterator
  80.                     sub_obj = self._get_sub_obj_recurse(obj, s)

File "/home/john/.virtualenvs/lfs/local/lib/python2.7/site-packages/model_utils/managers.py" in _get_sub_obj_recurse
  153.             node = getattr(obj, rel)

Exception Type: AttributeError at /quizzes/testquiz/take/
Exception Value: 'int' object has no attribute 'essay_question'

以下是essay应用程序的模型：

from __future__ import unicode_literals
from django.utils.encoding import python_2_unicode_compatible
from django.utils.translation import ugettext as _
from quiz.models import Question


@python_2_unicode_compatible
class Essay_Question(Question):

    def check_if_correct(self, guess):
        return False

    def get_answers(self):
        return False

    def get_answers_list(self):
        return False

    def answer_choice_to_string(self, guess):
        return str(guess)

    def __str__(self):
        return self.content

    class Meta:
        verbose_name = _("Essay style question")
        verbose_name_plural = _("Essay style questions")

编辑:问题模型如下：

@python_2_unicode_compatible
class Question(models.Model):
    """
    Base class for all question types.
    Shared properties placed here.
    """

    quiz = models.ManyToManyField(Quiz,
                                  verbose_name=_("Quiz"),
                                  blank=True)

    category = models.ForeignKey(Category,
                                 verbose_name=_("Category"),
                                 blank=True,
                                 null=True)

    sub_category = models.ForeignKey(SubCategory,
                                     verbose_name=_("Sub-Category"),
                                     blank=True,
                                     null=True)

    figure = models.ImageField(upload_to='uploads/%Y/%m/%d',
                               blank=True,
                               null=True,
                               verbose_name=_("Figure"))

    content = models.CharField(max_length=1000,
                               blank=False,
                               help_text=_("Enter the question text that "
                                           "you want displayed"),
                               verbose_name=_('Question'))

    explanation = models.TextField(max_length=2000,
                                   blank=True,
                                   help_text=_("Explanation to be shown "
                                               "after the question has "
                                               "been answered."),
                                   verbose_name=_('Explanation'))

    objects = InheritanceManager()

    class Meta:
        verbose_name = _("Question")
        verbose_name_plural = _("Questions")
        ordering = ['category']

    def __str__(self):
        return self.content

可以在此处找到其他模型和视图：https://github.com/tomwalker/django_quiz

任何帮助都是非常感谢的。

Answer 1

纵观您的代码，我认为问题出在您的SittingManager中。您正在执行以下操作：

 question_set = question_set.values_list('id', flat=True)

 if len(question_set) == 0:
    ...

我会推荐：

question_ids = question_set.values_list('id', flat=True)

if question_set.count() == 0:
    ...

# or less performant
# if len(list(question_ids)):
#    ...

并在您的进一步评估中与question_ids合作。有关这方面的更多信息，请浏览文档here

Answer 2

如果你运行的是Django1.9，这是一个Sportlich报告的issue with django-quiz-app-0.5.1。要修复它，请将从第306行开始的quiz/models.py中的代码更改为：

    if quiz.random_order is True:
        question_set = quiz.question_set.all() \
                                        .select_subclasses() \
                                        .order_by('?')
    else:
        question_set = quiz.question_set.all() \
                                        .select_subclasses()

至：

    if quiz.random_order is True:
        question_set = quiz.question_set.all() \
                                        .order_by('?')
    else:
        question_set = quiz.question_set.all()