投票URL
polls/urls.py：
# ex: /polls/5/vote/ url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),
创建投票form表单
polls/templates/polls/detail.html：
<h1>{{ question.question_text }}</h1>
{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}
<form action="{% url 'polls:vote' question.id %}" method="post">
{% csrf_token %}
{% for choice in question.choice_set.all %}
<input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}"/>
<label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br/>
{% endfor %}
<input type="submit" value="Vote"/>
</form>
代码解释：
{{ forloop.counter }} : for 循环次数
{% csrf_token %} : 解决POST请求跨域问题 Cross Site Request Forgeries
{% if %} {% endif %}:判断
{% for %} {% endfor %}:循环
投票Views 逻辑处理
投票 views vote in polls/views.py：
from django.http import HttpResponse, HttpResponseRedirect
from django.urls import reverse
def vote(request, question_id):
question = get_object_or_404(Question, pk=question_id)
try:
selected_choice = question.choice_set.get(pk=request.POST['choice'])
except (KeyError, Choice.DoesNotExist):
# Redisplay the question voting form.
return render(request, 'polls/detail.html', {
'question': question,
'error_message': "You didn't select a choice.",
})
else:
selected_choice.votes += 1
selected_choice.save()
# Always return an HttpResponseRedirect after successfully dealing
# with POST data. This prevents data from being posted twice if a
# user hits the Back button.
return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))
代码解释：
request.POST,request.GET： 分别可获得POST或GET方法的参数值，如上 request.POST['choice'] 可取得POST请求中，name值为choice的Value值。若POST参数中没有choice，则会产生KeyError。
HttpResponseRedirect：重定向跳转，提交成功后进行自动重定向跳转是web 开发的一个良好实践。防止数据提交两次。
投票结果页 Views 逻辑处理
views results in polls/views.py:
from django.shortcuts import get_object_or_404, render
def results(request, question_id):
question = get_object_or_404(Question, pk=question_id)
return render(request, 'polls/results.html', {'question': question})
投票结果显示 template
polls/templates/polls/results.html：
<h1>{{ question.question_text }}</h1>
<ul>
{% for choice in question.choice_set.all %}
<li>{{ choice.choice_text }} -- {{ choice.votes }} vote{{ choice.votes|pluralize }}</li>
{% endfor %}
</ul>
<a href="{% url 'polls:detail' question.id %}">Vote again?</a>
实现结果
1、访问detail.html：http://localhost:8000/polls/1/
2、选择后，点击vote投票，跳转到结果页 results.html
