Django(四)-搭建第一个应用(3)

一、问题详情页

html 复制代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>展示某个投票的问题和不带结果的选项列表</title>
</head>
<body>

<form action="{% url 'polls:vote' question.id %}"  method="post">
{% csrf_token %}
<fieldset>
    <legend><h1>{{ question.question_text }}</h1></legend>
    {% if error_message %}<p><strong> {{ error_message }}</strong> </p> {% endif %}

    {% 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>
        <li>{{ choice.choice_text }}</li>
    {% endfor %}
</fieldset>
<input type="submit" value="Vote">
</form>
</body>
</html>

二、问题结果页

html 复制代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1> {{ question.question_text }}</h1>
<ul>
    {% for choice in question.choice_set.all %}

        <li> {{ choice.choice_test }} -- {{ choice.votes }}</li>
    {%  endfor %}
</ul>

{# 跳转到某一问题的投票详情页#}
<a href="{% url 'polls:detail' question.id %}">vote again?</a>

</body>
</html>

三、投票处理器视图

python 复制代码

# 3.投票处理器：用于响应用户为某个问题的特定选项投票的操作
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):
        return render(
            request,
            "polls/detail.html",
            {
                "quesiton":question,
                "error_message":"You didn't select a choice"
            }
        )
    else:
        selected_choice.votes = F("votes") + 1
        selected_choice.save()
        return HttpResponseRedirect(reverse("polls:results",args=(question.id,)))

四、引入通用视图之前的urlCONF

python 复制代码

from django.urls import path

from . import views

# 为视图函数配置url
# name
# 设置app的命名空间,主要是为了区分不同app下相同名字的视图
app_name = "polls"
urlpatterns = [
    # 当 Django 响应一个请求时，它会从 urlpatterns 的第一项开始，按顺序依次匹配列表中的项，直到找到匹配的项。
    # 比如URLconf 在处理请求 https://www.example.com/myapp/ 时，它会尝试匹配 myapp/
    path("",views.index,name= "index"),

    path("<int:question_id>/",views.detail,name = "detail"),
    path("<int:question_id>/results/", views.results, name = "results"),
    path("<int:question_id>/vote/", views.vote, name = "vote"),
]

五、引入通用视图

python 复制代码

from django.db.models import F
from django.http import HttpResponse, Http404,HttpResponseRedirect
from django.shortcuts import render, get_object_or_404
from django.urls import reverse
from django.views.generic import ListView
from django.views import generic

# Create your views here.

from .models import Question,Choice

class indexView(generic.ListView):
    # 默认情况下，ListView使用一个叫做 <app name>/<model name>_list.html的默认模板
    # 因此默认模板为polls/index_list.html
    # 此例我本手动指定template_name为"polls/index.html"

    template_name = "polls/index.html"

    # 默认的上下文变量名(其对应的值会传递到index.html)为question_list(命名规则:模板名小写_list)
    # 因为之前的代码中,在index.html中引用的变量名都是latest_question_list,因此使用context_object_name覆盖默认的行为
    context_object_name = "latest_question_list"

    # 如果不重写get_queryset,而使用默认的 model = Question
    # 其实等价于 Question.objects.all()
    def get_queryset(self):
        """返回最近5个发布的问题"""
        return Question.objects.order_by("-pub_date")[:5]



    # latest_question_list = Question.objects.order_by("-pub_date")[:5]
    # context = {"latest_question_list":latest_question_list}
    # return  render(request,"polls/index.html",context)

    # output = ", ".join([q.question_text for q in latest_question_list])
    # return HttpResponse(output)


# 1.问题详情页：展示某个投票的问题和不带结果的选项列表
class detailView(generic.DetailView):
    model =  Question
    template_name = "polls/detail.html"

    # 404异常处理-传统方式
    # try:
    #     question = Question.objects.get(pk=question_id)
    # except Question.DoesNotExist:
    #     raise Http404("Quesition does not exit")

    # 404异常处理-利用Django提供的函数
    # question = get_object_or_404(Question,pk=question_id)
    # return render(request,"polls/detail.html",{"question":question})

# 2.问题结果页：展示某个投票的结果
class resultsView(generic.DetailView):
    model = Question
    template_name = "polls/result.html"

    # question = get_object_or_404(Question,pk= question_id)
    # return render(request,"polls/result.html",{"question":question})


# 3.投票处理器：用于响应用户为某个问题的特定选项投票的操作
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):
        return render(
            request,
            "polls/detail.html",
            {
                "quesiton":question,
                "error_message":"You didn't select a choice"
            }
        )
    else:
        selected_choice.votes = F("votes") + 1
        selected_choice.save()
        return HttpResponseRedirect(reverse("polls:results",args=(question.id,)))

六、引入通用视图之后的urlCONF

第二和第三个模式的路径字符串中匹配的模式名称已从 <question_id> 更改为 <pk>。这是因为我们将使用 DetailView 通用视图来替换我们的 detail() 和 results() 视图，它期望从 URL 中捕获的主键值被称为 "pk"。

python 复制代码

from django.urls import path

from . import views

# 为视图函数配置url
# name
# 设置app的命名空间,主要是为了区分不同app下相同名字的视图
app_name = "polls"
urlpatterns = [
    # 当 Django 响应一个请求时，它会从 urlpatterns 的第一项开始，按顺序依次匹配列表中的项，直到找到匹配的项。
    # 比如URLconf 在处理请求 https://www.example.com/myapp/ 时，它会尝试匹配 myapp/
    path("",views.indexView.as_view(),name= "index"),

    path("<int:pk>/",views.detailView.as_view(),name = "detail"),
    path("<int:pk>/results/", views.resultsView.as_view(), name = "results"),
    path("<int:question_id>/vote/", views.vote, name = "vote"),
]