Django-1.8.3新建一個簡單的News app——01初探urls views

上一篇，已經在F盤根目錄下建立了mysites文件，接下在cmd中輸入下列代碼：

F:\>cd mysites

F:\mysites>django-admin startapp news

此時F:/mysites/下爲：

F:/mysites
│  manage.py
│
├─mysites
│      settings.py
│      urls.py
│      wsgi.py
│      __init__.py
│
└─news
    │  admin.py
    │  models.py
    │  tests.py
    │  views.py
    │  __init__.py
    │
    └─migrations
            __init__.py

打開mysites/mysites/settings.py，在INSTALLED_APP中，添加 news

INSTALLED_APPS = (
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
   <span style="color:#ff0000;"> 'news', </span>    # 就是這個貨啦，每次添加後不要忘記 "<span style="color:#ff0000;">,</span>"
)

可以先到cmd中 python manage.py runserver， 就會出現如下信息：

F:\mysites>python manage.py runserver
Performing system checks...

System check identified no issues (0 silenced).

You have unapplied migrations; your app may not work properly until they are applied.
Run 'python manage.py migrate' to apply them.
August 27, 2015 - 18:24:42
Django version 1.8.3, using settings 'mysites.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.

此時，就可以在瀏覽器輸入 http://127.0.0.1:8000/，會看到下述信息。

再打開mysites/mysites/urls.py，輸入下列代碼：

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
   <span style="color:#ff0000;"> url(r'^news/', include('news.urls')),   # 這貨的目的就是，正則匹配 ^news/，url符合該正則的，就調用 news/urls.py 的相關方法。</span>
]

新建mysites/news/urls.py

from django.conf.urls import url
from news import views

urlpatterns = [
    url(r'^$', views.index),
]

下面以 http://127.0.0.1:8000/news 大概說一下我對這兩個urls.py的理解，

1.  當着瀏覽器中輸入上述鏈接時， 在mysites/mysites/urls.py中，正則匹配到，告知具體方法不知道，你自己去‘news.urls’中去找

2. 然後轉入news/urls.py， 發現正則匹配到了，告知調用 views下的index方法（當然此時，index我們還未設置）。如果沒有匹配的，網頁就會報錯啦。

我們再去設置news/views.py

from django.shortcuts import render
from django.http import HttpResponse
# Create your views here.
def index(request):
    return HttpResponse('Hello Django')

此時，在瀏覽器中輸入 http://127.0.0.1:8000/news 就會出現Hello Django 啦

當然也可return HttpResponse('<h1>HELLO DJANGO</h1>')