Django2.2帮助文档的第一个例子：一个简易的投票系统—Prat3_4

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发布于 2020-03-06 10:25:28

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发布于 2020-03-06 10:25:28

文章被收录于专栏：小明的数据分析笔记本

原文链接

https://docs.djangoproject.com/en/2.2/intro/tutorial01/

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开始搭建简易投票系统

创建项目

django-admin startproject mysite

创建app

cd mysite
django-admin startapp polls

在polls文件夹下新建一个urls.py，写上如下代码

from django.urls import path
from . import views


urlpatterns = [
    path('',views.index,name='index'),
]

在mysite文件夹下的urls.py文件夹下写上代码

from django.contrib import admin
from django.urls import path
from django.urls import include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('polls/',include('polls.urls')),
]

在polls文件夹下新建一个templates文件夹
在templates文件夹下新建一个index.html文件，在文件里写些内容

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>这是index页面</title>
</head>
<body>
<h1>这是index页面</h1>
</body>
</html>

在mysite文件夹下的settings.py文件中添加模板文件夹的路径

os.path.join(BASE_DIR,'polls/templates')

在polls文件夹下的views.py文件中添加代码

from django.shortcuts import render

# Create your views here.

def index(request):
    return render(request,'index.html')

试着运行服务器

python manage.py runserver

返回结果

image.png

注册app，在mysite文件夹下的settings.py文件中写入

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'polls.apps.PollsConfig',
]

在polls文件夹下的models.py文件中写入如下代码

import datetime
from django.db import models
from django.utils import timezone
# Create your models here.

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')

    def __str__(self):
        return self.question_text

    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)


class Choice(models.Model):
    question = models.ForeignKey(Question,on_delete = models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return self.choice_text

迁移数据库

python manage.py makemigrations polls
python manage.py sqlmigrate polls 0001
python manage.py migrate

用shell添加问题

from polls.models import Choice, Question
Question.objects.all()
from django.utils import timezone
q = Question(question_text="你的性别是?", pub_date=timezone.now())
q.save()
q.choice_set.create(choice_text='男', votes=0)
q.choice_set.create(choice_text='女', votes=0)
q.choice_set.create(choice_text='不告诉你', votes=0)
q = Question(question_text="你喜欢的运动是?", pub_date=timezone.now())
q.choice_set.create(choice_text='篮球', votes=0)
q.choice_set.create(choice_text='足球', votes=0)
q.choice_set.create(choice_text='排球', votes=0)
q.choice_set.create(choice_text='不告诉你', votes=0)
Question.objects.all()
Choice.objects.all()

创建超级管理员用户

python manage.py createsuperuser

依次输入用户名，邮箱，密码

运行服务器

python manage.py runserver

访问 http://127.0.0.1:8000/admin/ 结果

image.png

在polls文件夹下的admin.py文件中添加

from django.contrib import admin

# Register your models here.


from .models import Question

admin.site.register(Question)

刷新，重新访问http://127.0.0.1:8000/admin/

结果

image.png

image.png

更改views.py文件中的代码

from django.shortcuts import render
from django.shortcuts import get_object_or_404
from .models import Question

# Create your views here.

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

def detail(request,question_id):
    question = get_object_or_404(Question,pk=question_id)
    return render(request,'detail.html',context={'question':question})

更改polls文件夹下urls.py的代码

from django.urls import path
from . import views


urlpatterns = [
    path('',views.index,name='index'),
    path('<int:question_id>/',views.detail,name="detail"),
]

更改index.html文件中的代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>这是index页面</title>
</head>
<body>
<h1>这是index页面</h1>
{% if latest_question_list %}
    <ul>
        {% for question in latest_question_list %}
            <li><a href="{{ question.id }}">{{ question.question_text }}</a></li>
        {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}
</body>
</html>

在templates文件夹下新建文件detail.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>这是详情页面</title>
</head>
<body>
<h1>这是详情页面</h1>
<h2>{{ question.question_text }}</h2>
<ul>
{% for choice in question.choice_set.all %}
    <li>{{ choice.choice_text }}</li>
{% endfor %}
</ul>
</body>
</html>

结果

image.png

image.png

在polls文件夹下新建static文件夹，然后在这个文件夹下新建style.css文件

li a {
    color:green
}

最终代码 index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>这是index页面</title>
</head>
<body>
{% load static %}
<link rel="stylesheet" type="text/css" href="{% static 'style.css' %}">
<h1>这是index页面</h1>
{% if latest_question_list %}
    <ul>
        {% for question in latest_question_list %}
            <li><a href="{{ question.id }}">{{ question.question_text }}</a></li>
        {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}
</body>
</html>

detail.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>这是详情页面</title>
</head>
<body>
<h1>这是详情页面</h1>
<h2>{{ question.question_text }}</h2>
{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}

<form action="{% url '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 }}</labelfor>
    {% endfor %}
    <input type="submit" value="Vote">
</form>
<ul>
{% for choice in question.choice_set.all %}
    <li>{{ choice.choice_text }}</li>
{% endfor %}
</ul>
</body>
</html>

results.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>这是结果页面</title>
</head>
<body>
<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 'detail' question.id %}"> Vote again ?</a>
</body>
</html>

urls.py

from django.urls import path
from . import views


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

views.py

from django.shortcuts import render
from django.shortcuts import get_object_or_404
from django.http import Http404
from django.http import HttpResponseRedirect
from django.urls import reverse
from .models import Question


# Create your views here.

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

def detail(request,question_id):
    try:
        question = get_object_or_404(Question,pk=question_id)
    except Question.DoesNotExist:
        raise Http404("Question does not exist!")
    return render(request,'detail.html',context={'question':question})

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,'detail.html',context={'question':question,
                                                     'error_message':"You did not select a choice!"})
    else:
        selected_choice.votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('results',args=(question_id,)))

def results(request,question_id):
    question = get_object_or_404(Question,pk=question_id)
    return render(request,'results.html',context={'question':question})

model.py

import datetime
from django.db import models
from django.utils import timezone
# Create your models here.

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')

    def __str__(self):
        return self.question_text

    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)


class Choice(models.Model):
    question = models.ForeignKey(Question,on_delete = models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return self.choice_text