Python Django序列化返回一个空列表

你好，伙计，我是Django的新手。我使用RESTAPI和Django与我的android应用程序交互我在variable quest中获得了所需的数据。因为有多个问题，所以我使用filter而不是get

这是my Views.py：

class MapertablesViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows groups to be viewed or edited.
    """
    queryset = Mapertables.objects.all()
    serializer_class = MapertablesSerializer
    lookup_field = 'category_id'

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        #queryset = list(maps)
        #queryset =  serializers.serialize('json',maps)
        #print "AAAA ",queryset
        i = 0
        #quest ={}
        queryset = []
        queslist = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            #print 'qqqq  ',question.question_id
            #queryset =  serializers.serialize('json',[question,])
            choices = Choice.objects.filter(question=question.question_id)
            print choices
            #aaa = chain(question,choices)
            #print aaa
            #queryset =  serializers.serialize('json',[question,choices,])
            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            #data Here  {0: u'Highbury', 1: u'Selhurst Park', 2: u'The Dell', 3: u'Old Trafford', 'question': <Question: At which ground did Eric Cantona commit his "Kung Fu" kick ?>}
            serializer_class = CoustomeSerializer(queryset, many=True)
            print serializer_class.data
            #[]
            json = JSONRenderer().render(serializer_class.data)
            print 'JSON',json
            #[]
            i += 1

        queryset = queslist
        serializer_class = CoustomeSerializer(queryset,many=True)
        return queryset
        #print "questions",queslist
        #print "Ser ",ser.data

定义为显示以下内容的URL： 异常类型：KeyError 异常值：“类别\u id”

当我查询特定类别时，它返回： { “详细信息”：“未找到” }

Model.py文件如下所示：

from django.db import models

# Create your models here.
class Category(models.Model):
    category_name = models.CharField(max_length=200,default='1')
    def __str__(self):
        return self.category_name


class Question(models.Model):
    question_text = models.CharField(max_length=200)
    #category_name = models.ForeignKey(Category)
    pub_date = models.DateTimeField('date published')
    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)
    was_published_recently.admin_order_field = 'pub_date'
    was_published_recently.boolean = True
    was_published_recently.short_description = 'Published recently?'
    def __str__(self):
        return self.question_text


class Mapertables(models.Model):
    category_id = models.ForeignKey(Category)
    question_id = models.ForeignKey(Question)


class Choice(models.Model):
    question = models.ForeignKey(Question)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
    def __str__(self):
        return self.choice_text

我想从选项模块中获取所有与类别和选项相关的问题，这就是为什么get_queryset中的所有内容

请告诉我如何在MapertablesViewSet类中获取我所需的所有数据

---

如果您想让我发送完整的项目，请提前向我表示感谢，我将制作zip并将其上载到驱动器或其他地方。

您正在从

get\u queryset

方法返回一个空列表，因此列表视图中不会返回任何对象，

pk

无法检索特定对象

---

您似乎在

get\u queryset

方法中做了很多不相关的事情，它们可能是导致此问题的原因。您不应该在那里进行任何序列化，DRF将稍后为您处理。您应该在

filter\u queryset

方法中进行过滤，或者将其传递给DRF进行过滤。您也不能从该方法返回任何响应，只能返回一个queryset。

@Kevin Brown是对的，您不必担心序列化程序，也不必在

get\u queryset

方法上渲染任何内容，但我在您的

get\u queryset

方法中注意到，您没有向列表添加任何项目

queryset

，和

querylist

。我给你一个想法如下：

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        i = 0
        queryset = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            choices = Choice.objects.filter(question=question.question_id)
            print choices

            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            # Adding items to queryset list
            queryset.append(quest)
            i += 1

        # You should have values here on queryset list
        print queryset

        return queryset

---

至于URL，请确保将

category\u id

作为URL模式上的参数传递。类似于

url（r'^mapers/（？P\d+）/“

，如果您没有为此使用

路由器

。如果您将URL定义粘贴到这里会很好。好的，我希望它能帮助您更好地了解如何继续。

您看到quest和serializer_类的输出，这就是代码被破坏的地方。感谢您的时间。get_queryset中的内容是获取所有数据库e关于类别。我获取类别id并检索问题。获取问题的选项。是否有一种简单的方法。如果有，请提出建议。真的谢谢你。我还将研究filter_queryset

    def get_queryset(self):
        #print self.kwargs['category_id']
        maps = Mapertables.objects.filter(category_id=self.kwargs['category_id'])
        i = 0
        queryset = []
        for question in maps:
            quest = {}
            quest['question'] = question.question_id
            choices = Choice.objects.filter(question=question.question_id)
            print choices

            j = 0
            for option in choices:
                quest[j] = option.choice_text
                j += 1
            print 'data Here ',quest
            # Adding items to queryset list
            queryset.append(quest)
            i += 1

        # You should have values here on queryset list
        print queryset

        return queryset