入门笔记翻译整理自：https://docs.djangoproject.com/en/1.8/
*该笔记将使用一个关于投票网络应用（poll application）的例子来阐述Django的用法。
表单和通用视图（Forms&Generic Views）
1. 简单的表单
修改detail.html中的代码，使之含有<form>元素：
1 # polls/templates/polls/detail.html 2 3 <h1>{{ question.question_text }}</h1> 4 5 {% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %} 6 7 <form action="{%url 'polls:vote' question.id %}" method="post"> 8 {% csrf_token %} 9 {% for choice in question.choice_set.all %} 10 <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{choice.id }}" /> 11 <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br /> 12 {% endfor %} 13 <input type="submit" value="Vote" /> 14 </form>
以上代码：首先，为选项生成了radio按钮；其次，当你创建数据服务端（data server-side）的表单时，要始终使用method="post"；然后，forloop.counter对循环进行计数；最后，由于使用了POST方法，我们需要关心跨站请求伪造（Cross Site Request Forgeries），不过Django提供了对此的保护机制。
我们在入门基础【三】中创建了如下代码：
1 # polls/urls.py 2 3 url(r'^(?P<question_id>[0-9]+/vote/$', views.vote, name='vote'),
向polls/views.py中添加如下代码：
1 # polls/views.py 2 3 from django.shortcuts import get_object_or_404, render 4 from django.http import HttpResponseRedirect, HttpResponse 5 from django.core.urlresolvers import reverse 6 7 from .models import Choice, Question 8 # ... 9 def vote(request, question_id): 10 p = get_object_or_404(Question, pk=question_id) 11 try: 12 selected_choice = p.choice_set.get(pk=request.POST['choice']) 13 except (KeyError, Choice.DoesNotExist): 14 # Redisplay the question voting form. 15 return render(request, 'polls/detail.html',{ 16 'question': p, 17 ''error_message': "You didn't select a choice.", 18 }) 19 else: 20 selected_choice.vote += 1 21 selected_choice.save() 22 # Always return an HttpResponseRedirect after successfully dealing 23 # with POST data. This prevents data from being posted twice if a 24 # user hits the Back button. 25 return HttpResponseRedirect(reverse('polls:results', args=(p.id,)))
当有人在问题下投票后，vote()视图会重新定向至结果页面，该页面视图如下：
1 # polls/views.py 2 3 from django.shortcuts import get_object_or_404, render 4 5 def results(request, question_id): 6 question = get_object_or_404(Question, pk=question_id) 7 return render(request, 'polls/results.html', {'question': question})
现在，创建polls/results.html模板：
1 # polls/templates/polls/results.html 2 3 <h1>{{ question.question_text }}</h1> 4 5 <ul> 6 {% for choice in question.choice_set.all %} 7 <li>{{ choice.choice_text }} -- {{ choice.votes }} vote {{ choice.votes | pluralize }}</li> 8 {% endfor %} 9 </ul> 10 11 <a href="{% url 'polls:detail' question.id %}">Vote again?</a>
2. 使用通用视图
注意到，detail()和results()视图很简单，并且冗余。index()视图也很相似。
这些视图代表了一种常见情形：根据URL中的被传递参数，从数据库中获取数据，载入模板，返回渲染后的模板。对于此类情形，可以使用Django提供的通用视图系统。
为了使用通用视图进行代码简化，我们需要进行以下改变：
1.转换URLconf；2.删除陈旧不必要的视图；3.引入基于通用视图的新视图
3. 修改URLconf
1 # polls/urls.py 2 3 from django.conf.urls import url 4 5 from . import views 6 7 ulrpatterns = [ 8 url(r'^$', views.IndexView.as_view(), name='index'), 9 url(r'^(?P<pk>[0-9]+)/$', views.DetailView.as_view(), name='detail'), 10 url(r'^(?P<pk>[0-9]+)/results/$', views.ResultsView.as_view(), name='results'), 11 url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'), 12 ]
注意第二和第三个模式从question_id变成了pk。
4. 修改Views
1 # polls/views.py 2 3 from django.shortcuts import get_object_or_404, render 4 from django.http import HttpResponseRedirect 5 from django.core.urlresolvers import reverse 6 from django.views import generic 7 8 from .models import Choice, Question 9 10 class IndexView(generic.ListView): 11 template_name = 'polls/index.html' 12 context_object_name = 'latest_question_list' 13 14 def get_queryset(self): 15 """Return the last five published questions.""" 16 return Question.objects.order_by('-pub_date')[:5] 17 18 class DetailView(generic.DetailView): 19 model = Question 20 template_name = 'polls/detail.html' 21 22 class ResultsView(generic.DetailView): 23 model = Question 24 template_name = 'polls/results.html' 25 26 def vote(request, question_id): 27 ... # same as above
-- The End --