我在模板渲染期间收到“NoReverseMatch”错误

Question

Currently reading the Python Crash Course by Eric Matthes and I'm trying to code a simple learning lo using python and Django, but I keep getting an error when I try to enter the topics URL. The error seems to come from the base.html(the template), it says that learning_logs is not a registered namespace, even tho I have written it as a variable named app_name and have included it in the URLs.

Here's the code:

main urls.py:

from django.contrib import admin
from django.urls import path , include , re_path

app_name = 'learning_logs'

urlpatterns = [
    path('admin/', admin.site.urls),
    path('' , include(("learning_logs.urls", app_name ) ))
]

urls.py:

from django.urls import path , re_path
from . import views

app_name = 'learning_logs'
urlpatterns = [
    #Home page
    path('', views.index, name='index'),
    path('topics/', views.topics , name='topics'),
    re_path(r'^topics/(?P<topic_id>\d+)/$' , views.topic , name = 'topic'),
    re_path(r'^new_topic/$' , views.new_topic , name = 'new_topic'),
    re_path(r'^new_entry/(?P<topic_id>\d+)/$' , views.new_entry , name = 'new_entry'),
]

base.html:

     <p>
        <a href="{% url 'learning_logs:index' %}">Learning Log</a>
        <a href="{% url 'learning_logs:topics' %}">Topics</a>
    </p>

    {% block content %}
    {% endblock content %}

Error:

Answer 1

I think you need to fix the declarations in the main urls.py by removing the app_name and fixing the include.

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('' , include('learning_logs.urls'))
]

Answer 2

Just fix the main urls.py file as the following:

from django.contrib import admin
from django.urls import path , include , re_path


urlpatterns = [
    path('admin/', admin.site.urls),
    path('' , include(("learning_logs.urls", app_name='learning_logs') ))
]

Note the named parameter app_name= in include