is_paginated 对于 Django 中基于类的视图不能正常工作

Question

book_list.html

{% extends "base.html" %}
{% block content %}
<h3> Available books </h3>
{% if book_list %}
<ul>
    {% for book in book_list %}
     <li> <a href = "{{ book.get_absolute_url }}">{{book.title }}</a>    <small> by {{book.author }}</small></li>
     <p>{{ book.summary }}
    {% endfor %}
<ul>
{% endif %}
{% if is_paginated %}
  <div class="pagination">
      <span class="page-links">
          {% if page_obj.has_previous %}
              <a href="{{ request.path }}?page={{ page_obj.previous_page_number }}">previous</a>
          {% endif %}
          <span class="page-current">
              Page {{ page_obj.number }} of {{ page_obj.paginator.num_pages }}.
          </span>
          {% if page_obj.has_next %}
              <a href="{{ request.path }}?page={{ page_obj.next_page_number }}">next</a>
          {% endif %}
      </span>
  </div>
{% else %}
      <h4> pagination not working</h4>
{% endif %}
{% endblock %}

views.py 中的类：

class BookListView(generic.ListView):
  model = Book
  paginate_by = 2
  queryset =Book.objects.all()

urls.py：

 urlpatterns =[
 url('^$',views.index, name ='index'),  # matching with an empty string 
 url('^books/$',views.BookListView.as_view(),name ='books'), #the one to which I am adding the paginator
 url('^book/(?P<pk>\d+)/$',views.BookDetailView.as_view(),name='book-detail'),

]

图书模型：

class Book(models.Model):
  title=models.CharField(max_length=100)
  author = models.ForeignKey('Author',on_delete=models.SET_NULL,null = True)
  summary = models.TextField(max_length=200,help_text="Enter the description")
  isbn = models.CharField('ISBN',max_length=13 ,help_text='13 Character <a href="https://www.isbn-international.org/content/what-isbn">ISBN number</a>' )
  genre = models.ManyToManyField(Genre,help_text = 'selct a genre for this book')

  class Meta:
     ordering =["title"]
  def __str__(self):
     return self.title

  def get_absolute_url(self):
     return reverse('book-detail',args=[str(self.id)] )  

book_list 完美呈现，问题出在分页器上，is_paginated 条件不起作用，它执行 else 语句，我已经尝试了 3 个多小时，但找不到解决方案，我在做什么这里不见了？
Django 版本：1.11.2 蟒蛇：3.5

编辑： 更新 1：问题是 paginate_by 值是两个，并且要显示的总项目也是两个因此它没有启动 is_paginated 标签，当我添加一个项目超过 paginate_by 值时它工作正常。

Answer 1

使用这个，你的 if 条件有问题

{% extends "base.html" %}
{% block content %}
<h3> Available books </h3>
{% if object_list %}
    <ul>
        {% for book in object_list %}
         <li> <a href = "{{ book.get_absolute_url }}">{{book.title }}</a>    <small> by {{book.author }}</small></li>
         <p>{{ book.summary }}
        {% endfor %}
    <ul>

    {% if is_paginated %}
      <div class="pagination">
          <span class="page-links">
              {% if page_obj.has_previous %}
                  <a href="{{ request.path }}?page={{ page_obj.previous_page_number }}">previous</a>
              {% endif %}
              <span class="page-current">
                  Page {{ page_obj.number }} of {{ page_obj.paginator.num_pages }}.
              </span>
              {% if page_obj.has_next %}
                  <a href="{{ request.path }}?page={{ page_obj.next_page_number }}">next</a>
              {% endif %}
          </span>
      </div>
    {% else %}
          <h4> pagination not working</h4>
    {% endif %}
        {% else %}
        <h4> No book</h4>
{% endif %}
{% endblock %}