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Django分页功能的实现代码详解

2019-11-25 12:11:45
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Django分页功能的实现

打开命令行窗口,创建Django工程,使用以下命令:

django-admin startproject djpage

cd djpage

python manage.py startapp demo

使用PyCharm打开工程,在工程的同名文件夹的settings.py文件,注册应用,添加模板路径,修改部分的settings.py内容如下:

INSTALLED_APPS = [  'django.contrib.admin',  'django.contrib.auth',  'django.contrib.contenttypes',  'django.contrib.sessions',  'django.contrib.messages',  'django.contrib.staticfiles',  'demo.apps.DemoConfig']TEMPLATES = [  {    'BACKEND': 'django.template.backends.django.DjangoTemplates',    'DIRS': [os.path.join(BASE_DIR,'templates')],    'APP_DIRS': True,    'OPTIONS': {      'context_processors': [        'django.template.context_processors.debug',        'django.template.context_processors.request',        'django.contrib.auth.context_processors.auth',        'django.contrib.messages.context_processors.messages',      ],    },  },]

在工程同名文件的urls.py文件,添加到应用的视图的路由

from django.conf.urls import urlfrom django.contrib import adminfrom demo import viewsurlpatterns = [  url(r'^admin/', admin.site.urls),  url(r'page/(?P<id>/d+)/$',views.page)]

在应用的视图views.py文件,编写处理请求函数,实现分页显示一个列表的内容,这里列表也可以是查询集

from django.shortcuts import renderfrom django.core.paginator import Paginator# Create your views here.def page(request,id):  hello_list = [{'title':'hello'},{'title':'world'},        {'title':'hello1'},{'title':'world1'},        {'title':'hello2'},{'title':'world2'},        {'title':'hello3'},{'title':'world3'},        {'title':'hello4'},{'title':'world4'}]  pag = Paginator(hello_list, 2)  page = pag.page(int(id))  return render(request,template_name='home.html', context={'page': page})

在工程根目录新建templates文件夹,并创建一个home.html文件,代码如下:

<!DOCTYPE html><html lang="en"><head>  <meta charset="UTF-8">  <title>Title</title></head><body>  <ul>    {% for item in page %}    <li>{{item.title}}</li>    {% endfor %}  </ul>  {% if page.has_previous %}  <a href="/page/{{ page.previous_page_number }}" rel="external nofollow" rel="external nofollow" ><上一页</a>  {% endif %}  {# 遍历显示页码的链接 #}  {% for index in page.paginator.page_range %}  {# 判断是否是当前页 #}    {% if index == page.number %}      {{ index }}    {% else %}      <a href="/page/{{ index }}" rel="external nofollow" rel="external nofollow" >{{ index }}</a>    {% endif %}  {% endfor %}  {# 判断是否有下一页 #}  {% if page.has_next %}    <a href="/page/{{ page.next_page_number }}" rel="external nofollow" rel="external nofollow" >下一页></a>  {% endif %}</body></html>
<!DOCTYPE html><html lang="en"><head>  <meta charset="UTF-8">  <title>Title</title></head><body>  <ul>    {% for item in page %}    <li>{{item.title}}</li>    {% endfor %}  </ul>  {% if page.has_previous %}  <a href="/page/{{ page.previous_page_number }}" rel="external nofollow" rel="external nofollow" ><上一页</a>  {% endif %}  {# 遍历显示页码的链接 #}  {% for index in page.paginator.page_range %}  {# 判断是否是当前页 #}    {% if index == page.number %}      {{ index }}    {% else %}      <a href="/page/{{ index }}" rel="external nofollow" rel="external nofollow" >{{ index }}</a>    {% endif %}  {% endfor %}  {# 判断是否有下一页 #}  {% if page.has_next %}    <a href="/page/{{ page.next_page_number }}" rel="external nofollow" rel="external nofollow" >下一页></a>  {% endif %}</body></html>

page.paginator.page_range是页面总数

运行django服务器

python manage.py runserver

打开网页,输入

http://127.0.0.1:8000/page/1

显示效果图如下,分页成功

知识点扩展:

自定义分页的实例代码:

def book(request): # 从URL取参数(访问的页码) page_num = request.GET.get("page") try: # 将取出的page转换为int类型 page_num = int(page_num) except Exception as e: # 当输入的页码不是正经数字的时候 默认返回第一页的数据 page_num = 1  # 数据库总数据是多少条 total_count = models.Book.objects.all().count()  # 每一页显示多少条数据 per_page = 10  # 总共需要多少页码来展示 total_page, m = divmod(total_count, per_page) if m: total_page += 1  # 如果输入的页码数超过了最大的页码数,默认返回最后一页 if page_num > total_page: page_num = total_page  # 定义两个变量从哪里开始到哪里结束 data_start = (page_num - 1) * 10 data_end = page_num * 10  # 页面上总共展示多少页码 max_page = 11 if total_page < max_page: max_page = total_page  # 把从URL中获取的page_num 当做是显示页面的中间值, 那么展示的便是当前page_num 的前五页和后后五页 half_max_page = max_page // 2 # 根据展示的总页码算出页面上展示的页码从哪儿开始 page_start = page_num - half_max_page # 根据展示的总页码算出页面上展示的页码到哪儿结束 page_end = page_num + half_max_page  # 如果当前页减一半 比1还小, 不然页面上会显示负数的页码 if page_start <= 1: page_start = 1 page_end = max_page # 如果 当前页 加 一半 比总页码数还大, 不然页面上会显示比总页码还大的多余页码 if page_end >= total_page: page_end = total_page page_start = total_page - max_page + 1  # 从数据库取值, 并按照起始数据到结束数据展示 all_book = models.Book.objects.all()[data_start:data_end]   # 自己拼接分页的HTML代码 html_str_list = []  # # 加上首页 html_str_list.append('<li><a href="/book/?page=1" rel="external nofollow"  >首页</a></li>')  # 断一下 如果是第一页,就没有上一页 if page_num <= 1: html_str_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow"  ><span aria-hidden="true">«</span></a></li>') else: # 不是第一页,就加一个上一页的标签 html_str_list.append('<li><a href="/book/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow"   ><span aria-hidden="true">«</span></a></li>'.format(page_num - 1))  for i in range(page_start, page_end + 1): # 如果是当前页就加一个active样式类 if i == page_num:  tmp = '<li class="active"><a href="/book/?page={0}" rel="external nofollow" rel="external nofollow"  >{0}</a></li>'.format(i) else:  tmp = '<li><a href="/book/?page={0}" rel="external nofollow" rel="external nofollow"  >{0}</a></li>'.format(i)  html_str_list.append(tmp)  # 判断,如果是最后一页,就没有下一页 if page_num >= total_page: html_str_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow"  ><span aria-hidden="true">»</span></a></li>') else: # 不是最后一页, 就加一个下一页标签 html_str_list.append('<li><a href="/book/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow"   ><span aria-hidden="true">»</span></a></li>'.format(page_num + 1))  # 加上尾页 html_str_list.append('<li><a href="/book/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow"   >尾页</a></li>'.format(total_page))  page_html = "".join(html_str_list) return render(request, "book.html", {"all_book":all_book, "page_html":page_html})

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