Django学习笔记

在project中创建app

• 一个Django包含了很多的app，每个app都有一个文件夹

1. python3 manage.py startapp appname创建一个文件夹。
2. 文件夹下添加view.py文件
3. 文件夹下添加urls.py文件
4. 在主app中urls.py中包含这个app中urls

在app使用model(database table)

• model 的class variables就是database中列

1. models.py 增加model(table)
2. 主app中settings.py INSTALLED_APPS中添加 app
3. python3 manage.py makemigrations appname
4. python3 manage.py migrate

创建template

避免每次修改view都需要改动python的代码

1. 在app文件夹中创建一个template/appname/index.html的文件
2. 更新views.py(loader载入模板，render映射模板)

template教程 docs.djangoproject.com/en/3.2/topi…

Example with LTE admin

1. pip3 install django django-adminlte-3

2. django-admin startproject demoproject to create a project.

3. set ALLOWED_HOSTS = ["*"] in setttings.py to allow all ip.

4. python3 manage.py startapp myapp to create an app

5. create a myapp/template/myapp/show.html

   {% extends 'adminlte/base.html' %}
   
   {% block title %}Overview{% endblock %}
   {% block content %}
   <canvas id="myChart" width="400" height="400"></canvas>
   <script src="https://cdn.jsdelivr.net/npm/chart.js@2.9.0"></script>
   <script>
   var ctx = document.getElementById('myChart').getContext('2d');
   var myChart = new Chart(ctx, {
       type: 'bar',
       data: {
           labels: {{x}},
           datasets: [{
               label: '# of Votes',
               data: {{y}},
               backgroundColor: [
                   'rgba(255, 99, 132, 0.2)',
                   'rgba(54, 162, 235, 0.2)',
                   'rgba(255, 206, 86, 0.2)',
                   'rgba(75, 192, 192, 0.2)',
                   'rgba(153, 102, 255, 0.2)',
                   'rgba(255, 159, 64, 0.2)'
               ],
               borderColor: [
                   'rgba(255, 99, 132, 1)',
                   'rgba(54, 162, 235, 1)',
                   'rgba(255, 206, 86, 1)',
                   'rgba(75, 192, 192, 1)',
                   'rgba(153, 102, 255, 1)',
                   'rgba(255, 159, 64, 1)'
               ],
               borderWidth: 1
           }]
       },
       options: {
           scales: {
               y: {
                   beginAtZero: true
               }
           }
       }
   });
   </script>
   {% endblock %}
   

6. edit views.py in myapp folder

   from django.shortcuts import render
   from django.http import HttpResponse
   from .models import MyOwnData
   # Create your views here.
   def index(request):
       if not MyOwnData.objects.count():
           for i in range(10):
               item = MyOwnData()
               item.x = i
               item.y = 2*i
               item.save()
       x =list(MyOwnData.objects.values_list("x",flat=True))
       y = list(MyOwnData.objects.values_list("y",flat=True))
       return render(request,"myapp/show.html",{"x":x,"y":y})
   

7. add urls.py in myapp folder

   from django.urls import path
   from . import views
   
   urlpatterns = [
       path('', views.index, name='index'),
   ]
   

8. edit urls.py in main app folder to register

   from django.contrib import admin
   from django.urls import path, include
   
   urlpatterns = [
       path('myapp/', include('myapp.urls')),
       path('admin/', admin.site.urls),
   ]
   

9. add models.py in myapp folder

   from django.db import models
   
   # Create your models here.
   class MyOwnData(models.Model):
       x = models.FloatField(default=0.0)
       y = models.FloatField(default=0.0)
   

10. edit settings.py to register model

    INSTALLED_APPS = [
        'adminlte3',
        'myapp.apps.MyappConfig',
        'django.contrib.admin',
        'django.contrib.auth',
        'django.contrib.contenttypes',
        'django.contrib.sessions',
        'django.contrib.messages',
        'django.contrib.staticfiles',
    ]
    

11. python3 manage.py makemigrations myapp && python3 manage.py migrate

12. python3 manage.py runserver 0:6000