项目结构
1.建立项目
File -->> New Project...
第一个Location是项目所在的目录，第二个Location是项目独立的Python运行环境，我们称之为Virtualenv。Base interpreter是Python安装目录下的python.exe。 刚创建的Django项目如下所示：
在Terminal窗口输入命令python manage.py runserver也可以启动项目。
在浏览器中访问http://127.0.0.1:8000/，看到下面这个页面表明项目到目前为止一切正常。
2.创建应用程序
Django项目由一系列应用程序组成，它们协同工作，让项目成为一个整体。
实际上，PyCharm的Terminal窗口已经处于Django项目独立的运行环境，执行python manage.py startapp learning_logs命令创建一个应用程序：
创建完应用程序后，就可以在项目中看到新增的应用程序的目录。
2.1 定义模型
# untitled/learning_logs/models.pyfrom django.db import modelsclass Topic(models.Model): """A topic the user is learning about.""" text = models.CharField(max_length=200) date_added = models.DateTimeField(auto_now_add=True) def __str__(self): """Return a string representation of the model.""" return self.textclass Entry(models.Model): """Something specific learned about a topic.""" topic = models.ForeignKey('Topic', on_delete=models.CASCADE) text = models.TextField() date_added = models.DateTimeField(auto_now_add=True) class Meta: verbose_name_plural = 'entries' def __str__(self): """Return a string representation of the model.""" return self.text[:50] + "..." 2.2 激活模型
# untitled/untitled/settings.py# ···# Application definitionINSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', # 我的应用程序 'learning_logs',]# ···
2.3 创建数据库
接着，先后执行命令python manage.py makemigrations learning_logs和python manage.py migrate，前者生成一个文件0001_initial.py告诉Django如何修改数据库，后者就让Django修改数据库了。
2.4 Django管理网站
为应用程序定义模型时，Django提供的管理网站让你能够轻松地处理模型。
创建超级用户：
向管理网站注册模型：
# untitled/learning_logs/admin.pyfrom django.contrib import admin# Register your models here.from learning_logs.models import Topic, Entryadmin.site.register(Topic)admin.site.register(Entry)
使用超级用户访问管理网站http://127.0.0.1:8000/admin/。
我们可以在管理网站管理模型的数据：
2.5 Django shell
输入一些数据后，就可通过交互式终端会话以编程方式查看这些数据了。这种交互式环境称为Django shell，是测试项目和排除其故障的理想之地。
3.创建网页
使用Django创建网页的过程通常分三个阶段：定义URL、编写视图和编写模板。
每个URL都被映射到特定的视图——视图函数获取并处理网页所需的数据。视图函数通常调用一个模板，后者生成浏览器能够理解的网页。3.1 映射URL
http://127.0.0.1:8000/默认返回Django网站，我们修改这一点，将这个URL映射到“学习笔记”的主页。
# untitled/untitled/urls.pyfrom django.contrib import adminfrom django.urls import pathfrom django.conf.urls import include, urlurlpatterns = [ path('admin/', admin.site.urls), url(r'', include('learning_logs.urls', namespace='learning_logs'))] """定义learning_logs的URL模式"""# untitled/learning_logs/urls.pyfrom django.conf.urls import urlfrom . import viewsapp_name = 'learning_logs'urlpatterns = [ # 主页 url(r'^$', views.index, name='index'),]
3.2 编写视图
# untitled/learning_logs/views.pyfrom django.shortcuts import render# Create your views here.def index(request): """学习笔记的主页""" return render(request, 'learning_logs/index.html')
3.3 编写模板
Learning Log
Learning Log helps you keep track of your learning, for my topic you're learning about.
3.3.1 父模板
{% block content %}{% endblock %}
3.3.2 子模板
{% extends "learning_logs/base.html" %}{% block content %} Learning Log helps you keep track of your learning, for any topic you're learning about.
{% endblock content %} 显示所有主题的页面
"""定义learning_logs的URL模式"""# untitled/learning_logs/urls.pyfrom django.conf.urls import urlfrom . import viewsapp_name = 'learning_logs'urlpatterns = [ # 主页 url(r'^$', views.index, name='index'), url(r'^topics/$', views.topics, name='topics'),]
# untitled/learning_logs/views.py#···def topics(request): topics = Topic.objects.order_by('date_added') context = {'topics' : topics} return render(request, 'learning_logs/topics.html', context)# ··· {% extends "learning_logs/base.html" %}{% block content %} Topics
- {% for topic in topics %}
- { { topic }} {% empty %}
- No topics have been added yet. {% endfor %}
显示特定主题的页面
"""定义learning_logs的URL模式"""# untitled/learning_logs/urls.pyfrom django.conf.urls import urlfrom . import viewsapp_name = 'learning_logs'urlpatterns = [ # 主页 url(r'^$', views.index, name='index'), url(r'^topics/$', views.topics, name='topics'), url(r'^topics/(?P\d+)/$', views.topic, name='topic'),]
# untitled/learning_logs/views.py#···def topic(request, topic_id): """Show a single topic, and all its entries.""" topic = Topic.objects.get(id=topic_id) entries = topic.entry_set.order_by('-date_added') context = {'topic': topic, 'entries': entries} return render(request, 'learning_logs/topic.html', context)#··· {% extends 'learning_logs/base.html' %}{% block content %} Topic: {
{ topic }} Entries:
- {% for entry in entries %}
-
{
{ entry.date_added|date:'M d, Y H:i' }}{
{ entry.text|linebreaks }} {% empty %} - There are no entries for this topic yet. {% endfor %}
参考资料：《Python编程从入门到实践》—【美】Eric Matthes 著