django 分页记要

一、在创建完项目、app 、以后在与 manage.py 同级的文件下 创建一个 utils 目录 （用于存储分页功能），在此目录下创建一个pager.py

∆∆ ： 代码示例： 

class PageInfo(object):
    def __init__(self,current_page,all_count,per_page,base_url,show_page=11):
        """

        :param current_page:
        :param all_count: 数据库总行数
        :param per_page:  每页显示 的函数
        :param base_url:
        :param show_page:

        """

        try:
            self.current_page=int(current_page)
        except Exception as e:
            self.current_page=1
        self.per_page=per_page

        a,b=divmod(all_count,per_page)

        if b:
            a=a+1
        self.all_pager=a
        self.show_page=show_page
        self.base_url=base_url

    def start(self):
        return (self.current_page-1)*self.per_page
    def end(self):
        return self.current_page*self.per_page

    def pager(self):
        page_list=[]

        half=int((self.show_page-1)/2)

        if self.all_pager<self.show_page:
            begin=1
            stop=self.all_pager+1

        else:
            if self.current_page<=half:
                begin=1
                stop=self.show_page+1
            else:
                if self.current_page+half > self.all_pager:
                    begin=self.all_pager-self.show_page+1
                    stop=self.all_pager+1
                else:
                    begin=self.current_page-half
                    stop=self.current_page+half+1

        if self.current_page<=1:
            prev="<li><a href='#'>上一页</a></li>"

        else:
            prev="<li><a href='%s?page=%s'>上一页</a></li>"%(self.base_url,self.current_page-1,)

        page_list.append(prev)

        for i in range(begin,stop):
            if i==self.current_page:
                temp="<li class='active'><a href='%s?page=%s'>%s</a></li>"%(self.base_url,i,i)

            else:
                temp="<li><a href='%s?page=%s'>%s</a></li>"%(self.base_url,i,i,)
            page_list.append(temp)

        if self.current_page>=self.all_pager:
            nex="<li><a href='#'>下一页</a></li>"

        else:
            nex="<li><a href='%s?page=%s'>下一页</a></li>"%(self.base_url,self.current_page+1)
        page_list.append(nex)

        return ''.join(page_list)

二、app下的views.py 文件 导入 pager.py,  并渲染到 html 页面：

from django.shortcuts import render,redirect,HttpResponse
from django.views import View
from CBV import models
from django.core.paginator import Paginator, Page,PageNotAnInteger,EmptyPage
# Create your views here.

class Login(View):

    '''
    FORM  表单只有GET POST 两种
    AJAX的提交方式
    默认都认为
    get  查
    put 更新
    post 创建
    delete 删除

    '''
    def dispatch(self, request, *args, **kwargs):
        print('before')
        obj=super(Login,self).dispatch(request,*args,**kwargs)
        print('after')
        return obj



    def get(self,request):
        print(2)
        return render(request,'login.html')

    def post(self,request):
        print(32323)
        print(request.POST.get('user'))
        result=models.UserInfo.objects.all()
        for obj in result:
            print(obj.name,obj.age,obj.ut_id)
        return render(request,'login.html')




def index(request):
    #测试创建300条数据
    # for i in range(300):
    #     name='root'+str(i)
    #     models.UserInfo.objects.create(name=name,age=18,ut_id=1)

    current_page=request.GET.get('page')
    user_list=models.UserInfo.objects.all()
    paginator=Paginator(user_list,10)
        # current_page=int(current_page)
    try:
        posts=paginator.page(current_page)
    except PageNotAnInteger as e:
        posts = paginator.page(1)

    except EmptyPage as e:
        posts=paginator.page(1)
    # userlist=models.UserInfo.objects.all()

    # paginator = Paginator(userlist, 10)  # 每页显示10条
    # posts=paginator.page(current_page) # 当前显示第几页
    #posts  中有一个叫 object_list 是分页之后的数据
    #has_previous
    #next_page
    #pre_page
    #page_range
    return render(request,'index.html',{'posts':posts})


# class PageInfo(object):
#     def __init__(self,current_page,all_count,per_page,base_url,show_page=11):
#         try:
#             self.current_page = int(current_page) #数据库总行数
#             # self.per_page = per_page #每页显示函数
#         except Exception as e:
#             self.current_page=1
#
#         self.per_page=per_page
#
#         a,b=divmod(all_count,per_page)
#
#         if b:
#             a = a + 1
#         self.all_pager=a
#
#         self.show_page=show_page
#
#         self.base_url=base_url
#
#     def start(self):
#         return (self.current_page-1 ) * self.per_page
#
#     def end(self):
#         return self.current_page * self.per_page
#
#     def pager(self):
#
#         page_list=[]
#
#         half=int((self.show_page-1)/2)
#
#         #如果数据总页数<11
#         if self.all_pager<self.show_page:
#             begin=1
#             stop = self.all_pager + 1
#
#             #如果数据总页数 >11
#         else:
#             #如果当前页 <=5，让其永远显示 1到11页
#             if self.current_page <= half:
#                 begin=1
#                 stop=self.show_page+1
#             else:
#                 if self.current_page + half > self.all_pager:
#
#                     begin = self.all_pager - self.show_page + 1
#
#                     stop = self.all_pager + 1
#
#                 else:
#                     begin=self.current_page - half
#
#                     stop=self.current_page + half + 1
#
#         if self.current_page <= 1:
#
#             prev = "<li><a href='#'>上一页</a></li>"
#
#         else:
#
#             prev="<li><a href='/custom.html?page=%s'>上一页</a></li>"%(self.current_page-1,)
#
#         page_list.append(prev)
#
#         for i in range(begin,stop):
#             if i == self.current_page:
#                 temp="<li class='active'><a href='/custom.html?page=%s'>%s</a></li>"%(i,i,)
#             else:
#                 temp = "<li><a href='/custom.html?page=%s'>%s</a></li>"%(i,i,)
#             page_list.append(temp)
#
#         #下一页
#         if self.current_page >= self.all_pager:
#             nex="<li><a href='#'>下一页</a></li>"
#         else:
#             nex="<li><a href=/custom.html?page=%s'>下 一页<a/></li>"%(self.current_page+1,)
#         page_list.append(nex)
#
#
#         return ''.join(page_list)
from utils.pager import PageInfo

def custom(request):
    #表示用户当前想访问的页码：
    # current_page=request.GET.get('page')
    # print(current_page,'-----------')

    # current_page = int(current_page)


    #每页显示 数据的个数
    # per_page = 10




    # 假如 是第一页： 数据 是：0--10
    # 第二页： 10：20
    # 第三页  20：30

    # start=(current_page-1)*per_page
    # end=current_page*per_page
    # user_list=models.UserInfo.objects.all()[start:end]#起始位置：结束位置
    # return render(request,'custom.html',{'user_list':user_list})
    #访问方式http://127.0.0.1:9000/custom.html?page=4

    all_count=models.UserInfo.objects.all().count()

    page_info=PageInfo(request.GET.get('page'),all_count,10,'/custom.html',11)

    user_list=models.UserInfo.objects.all()[page_info.start():page_info.end()]

    return render(request,'custom.html',{'user_list':user_list,'page_info':page_info})

三、templates 下的html页面 将结果拿到

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="/static/bootstrap-3.3.7-dist/css/bootstrap.css" />
</head>
<body>
    <h1>用户列表 </h1>
        <ul>
            {% for row in user_list %}
                <li>{{ row.name }}</li>  #获取数据库内容。
            {% endfor %}
        </ul>

    <nav aria-label="Page navigation"> 
        <ul class="pagination">
            {{ page_info.pager|safe }}   #拿到页码
        </ul>
    </nav>
</body>
</html>

四、页面