我面临一个奇怪的问题，至少对于一个python / django noob来说这很奇怪;）
从我的 models.py 调用django.core.urlresolvers.reverse（）引发'NoneType'对象无法调用。当我从shell执行相同的行时，它工作正常。
我完全不知道为什么会这样。
贝壳：
$ from django.core.urlresolvers import reverse
$ reverse('images:view', args=[1])
'/images/1/'
models.py
from django.db import models
from django.core.urlresolvers import reverse
class Image(models.Model):
image = models.ImageField(upload_to='images')
image_caption = models.CharField(max_length=80, verbose_name='Caption')
uploaded_at = models.DateTimeField(auto_now_add=True, verbose_name='Date Uploaded')
modified_at = models.DateTimeField(auto_now=True, verbose_name='Date Modified')
def __str__(self):
return self.image_caption
def edit_image(self):
return '<a href="%s">Edit</a>' % reverse('images:view', args=[self.id])
edit_image.short_description = 'Edit Image'
edit_image.allow_tags = True
admin.py 在此处重新edit_image
from django.contrib import admin
from images.models import Image
class ImageAdmin(admin.ModelAdmin):
search_fields = ['image_caption']
list_display = ['id', 'image_caption', 'edit_image']
admin.site.register(Image, ImageAdmin)
url我试图在图片命名空间内反转
url(r'^(?P<pk>\d+)/$', views.DetailView.as_view(), name='view'),
我尝试了什么？
TRACEBACK
Template error:
In template /home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/contrib/admin/templates/admin/change_list.html, error at line 91
'NoneType' object is not callable
81 : {% endif %}
82 : {% endblock %}
83 :
84 : <form id="changelist-form" action="" method="post"{% if cl.formset.is_multipart %} enctype="multipart/form-data"{% endif %}>{% csrf_token %}
85 : {% if cl.formset %}
86 : <div>{{ cl.formset.management_form }}</div>
87 : {% endif %}
88 :
89 : {% block result_list %}
90 : {% if action_form and actions_on_top and cl.full_result_count %}{% admin_actions %}{% endif %}
91 : {% result_list cl %}
92 : {% if action_form and actions_on_bottom and cl.full_result_count %}{% admin_actions %}{% endif %}
93 : {% endblock %}
94 : {% block pagination %}{% pagination cl %}{% endblock %}
95 : </form>
96 : </div>
97 : </div>
98 : {% endblock %}
99 :
Traceback:
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/core/handlers/base.py" in get_response
139. response = response.render()
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/response.py" in render
105. self.content = self.rendered_content
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/response.py" in rendered_content
82. content = template.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in render
140. return self._render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in _render
134. return self.nodelist.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in render
840. bit = self.render_node(node, context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/debug.py" in render_node
78. return node.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/loader_tags.py" in render
123. return compiled_parent._render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in _render
134. return self.nodelist.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in render
840. bit = self.render_node(node, context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/debug.py" in render_node
78. return node.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/loader_tags.py" in render
123. return compiled_parent._render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in _render
134. return self.nodelist.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in render
840. bit = self.render_node(node, context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/debug.py" in render_node
78. return node.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/loader_tags.py" in render
62. result = block.nodelist.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in render
840. bit = self.render_node(node, context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/debug.py" in render_node
78. return node.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/loader_tags.py" in render
62. result = block.nodelist.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in render
840. bit = self.render_node(node, context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/debug.py" in render_node
78. return node.render(context)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/template/base.py" in render
1196. _dict = func(*resolved_args, **resolved_kwargs)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/contrib/admin/templatetags/admin_list.py" in result_list
288. 'results': list(results(cl))}
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/contrib/admin/templatetags/admin_list.py" in results
266. yield ResultList(None, items_for_result(cl, res, None))
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/contrib/admin/templatetags/admin_list.py" in __init__
258. super(ResultList, self).__init__(*items)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/contrib/admin/templatetags/admin_list.py" in items_for_result
185. f, attr, value = lookup_field(field_name, result, cl.model_admin)
File "/home/ankit/Desktop/Python/Workspace/VirtualEnv3.3.2/local/lib/python3.3/dist-packages/django/contrib/admin/util.py" in lookup_field
258. value = attr()
File "/home/ankit/Desktop/Python/Workspace/SnapShare/images/models.py" in edit_image
30. return '<a href="%s">Edit</a>' % reverse('images:view', args=[self.id])
Exception Type: TypeError at /admin/images/image/
Exception Value: 'NoneType' object is not callable
Python版本： 3.3.2
Django版本： 1.6.2
提前致谢：）
答案 0 :(得分：0)
在模型的方法中使用reverse_lazy应该可以解决问题（即使你尝试过）。这应该允许您在最终加载URL时使用callable。
将模型方法移动到ModelAdmin方法，这里是“copy-paste-ready”片段：
class ImageAdmin(admin.ModelAdmin):
# ... the rest of the class ... #
def edit_image(self, obj):
return '<a href="%s">Edit</a>' % reverse('images:view', args=[obj.id])
edit_image.short_description = 'Edit Image'
edit_image.allow_tags = True
在模型中使用reverse可能是导致此行为的原因。
模型可能过早加载（在urlconf完成之前），因此反向方法尚未定义。