NoReverseMatch - 'viewflow‘不是已注册的命名空间

Question

当尝试从官方烹饪书运行自定义UI应用程序("parcel")以获得视图流时，我得到以下错误：

/parcel/ NoReverseMatch /5/start/21/detail/ 'viewflow‘不是已注册的命名空间

我拍了张截图：

​

这是回溯：

Environment:


Request Method: GET
Request URL: http://localhost:8000/parcel/delivery/5/start/21/detail/

Django Version: 1.10.7
Python Version: 3.4.0
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'material',
 'material.frontend',
 'viewflow',
 'viewflow.frontend',
 'apps.parcel']
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.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']


Template error:
In template /Users/paul/delete-viewflows/templates/parcel/delivery/task_detail.html, error at line 0
   'viewflow' is not a registered namespace   1 : {% extends 'viewflow/flow/base_task.html' %}
   2 : {% load viewflow %}
   3 : 
   4 : {% block nav_parcels_cls %}class="active"{% endblock %}
   5 : 
   6 : {% block task_actions %}
   7 : {% flowurl activation.task 'execute' user=request.user as execute_url %}
   8 : {% if execute_url %}
   9 : <a href="{{ execute_url }}" class="btn primary">Execute</a>
   10 : {% endif %}


Traceback:

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/urls/base.py" in reverse
  77.                 extra, resolver = resolver.namespace_dict[ns]

During handling of the above exception ('viewflow'), another exception occurred:

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/core/handlers/exception.py" in inner
  42.             response = get_response(request)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/core/handlers/base.py" in _get_response
  217.                 response = self.process_exception_by_middleware(e, request)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/core/handlers/base.py" in _get_response
  215.                 response = response.render()

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/response.py" in render
  109.             self.content = self.rendered_content

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/response.py" in rendered_content
  86.         content = template.render(context, self._request)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/backends/django.py" in render
  66.             return self.template.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  208.                     return self._render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in _render
  199.         return self.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  174.         return compiled_parent._render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in _render
  199.         return self.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  174.         return compiled_parent._render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in _render
  199.         return self.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  174.         return compiled_parent._render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in _render
  199.         return self.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  174.         return compiled_parent._render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in _render
  199.         return self.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  174.         return compiled_parent._render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in _render
  199.         return self.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  70.                 result = block.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  70.                 result = block.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/loader_tags.py" in render
  70.                 result = block.nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/defaulttags.py" in render
  209.                     nodelist.append(node.render_annotated(context))

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/defaulttags.py" in render
  315.                 return nodelist.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  994.                 bit = node.render_annotated(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render_annotated
  961.             return self.render(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in render
  1044.             output = self.filter_expression.resolve(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in resolve
  711.                 obj = self.var.resolve(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in resolve
  852.             value = self._resolve_lookup(context)

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/template/base.py" in _resolve_lookup
  915.                             current = current()

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/viewflow/frontend/apps.py" in index_url
  55.         return reverse('viewflow:index')

File "/Users/paul/.pyenv/versions/dj-viewflow/lib/python3.4/site-packages/django/urls/base.py" in reverse
  87.                     raise NoReverseMatch("%s is not a registered namespace" % key)

Exception Type: NoReverseMatch at /parcel/delivery/5/start/21/detail/
Exception Value: 'viewflow' is not a registered namespace

我试图在我的项目urls中寻找一个视图流中的urls.py，但是什么也找不到。

我怎么才能解决这个问题？

Answer 1

UPDATE：有关实际正确答案，请参见下面的注释。

问题是我错过了urls.py项目的urls.py。这是在示例代码中缺少的。这是工作的urls.py

from django.contrib import admin
from django.conf.urls import include, url
from django.views import generic
from material.frontend import urls as frontend_urls

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url('^$', generic.TemplateView.as_view(template_name='parcel/index.html')),
    url('^parcel/', include('apps.parcel.urls', namespace='parcel')),
    url('^accounts/', include('django.contrib.auth.urls')),
    url(r'', include(frontend_urls)),
]