Django 2.0 学习(19)：Django 分页器

Django 分页器

要使用Django实现分页功能，必须从Django中导入Paginator模块(painator - 分页器)

views.py

from django.shortcuts import render

from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger

from BookSite.models import *

def index(request):

"""

批量导入数据

book_list = []

for i in range(100):

book_list.append(Book(title="book"+str(i), price=30+i**2))

Book.objects.bulk_create(book_list)

"""

"""

分页器的使用

book_list = Book.objects.all()

paginator = Paginator(book_list, 10)

print("count:", paginator.count)        # 总数居

print("num_pages", paginator.num_pages)     # 总页数

print("page_range", paginator.page_range)   # 页面的列表

page_one = paginator.page(1)        # 第一页的page对象

for i in range(page_one):           # 遍历第1页的所有数据对象

    print(i)

print(page_one.object_list)         # 第1页所有数据

page_two = paginator.page(2)

print(page_two.has_next())                  # 是否有下一页

print(page_two.next_page_number())          # 下一页的页码

print(page_two.has_previous())              # 是否有上一页

print(page_two.previous_page_number())      # 上一页的页码

# 抛出错误

page = paginator.page(12)               # Error:EmptyPage

page = paginator.page("z")              # Error:PageNotAnInteger

"""

book_list = Book.objects.all()

paginator = Paginator(book_list, 10)

page = request.GET.get("page", 1)

current_page = int(page)

try:

    print(page)

    book_list = paginator.page(page)

except PageNotAnInteger:

    book_list = paginator.page(1)

except EmptyPage:

    book_list = paginator.page(paginator.num_pages)

return render(request, "index.html", {

    "book_list": book_list,

    "paginator": paginator,

    "current_page": current_page

})

def retrieve(request):

"""

批量导入

book_list = []

for i in range(100):

book_list.append(models.Book(title="book"+str(i), price=20+i*i))

models.Book.objects.bulk_create(book_list)

"""

book_list = Book.objects.all()              # book_list打印的是一个对象 查询所有的书

paginator = Paginator(book_list, 5)            # 这里的book_list必须是一个集合对象，把所有的书分页，每页5个

print(paginator.page_range)                 # range(1, 4)

amount = request.GET.get("page", 2)         # 得到页数范围 默认有1页

print(amount, type(amount))

book_list = paginator.page(amount)          # 显示第1页的内容

return render(request, "retrieve.html", {

    "book_list": book_list,

    "page_range": paginator.page_range,

    "amount": int(amount),

    "paginator": paginator

})



**index.html**

```html

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

    <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"

    integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

</head>

<body>

<div class="container">

    <h4>分页器</h4>

    <ul>

        {% for book in book_list %}

             <li>{{ book.title }} -----{{ book.price }}</li>

        {% endfor %}

     </ul>

    <ul class="pagination" id="pager">

                 {% if book_list.has_previous %}

                    <li class="previous"><a href="/index/?page={{ book_list.previous_page_number }}">上一页</a></li>

                 {% else %}

                    <li class="previous disabled"><a href="#">上一页</a></li>

                 {% endif %}

                 {% for num in paginator.page_range %}

                     {% if num == currentPage %}

                       <li class="item active"><a href="/index/?page={{ num }}">{{ num }}</a></li>

                     {% else %}

                       <li class="item"><a href="/index/?page={{ num }}">{{ num }}</a></li>

                     {% endif %}

                 {% endfor %}

                 {% if book_list.has_next %}

                    <li class="next"><a href="/index/?page={{ book_list.next_page_number }}">下一页</a></li>

                 {% else %}

                    <li class="next disabled"><a href="#">下一页</a></li>

                 {% endif %}

            </ul>

</div>

</body>

</html>

分页器扩展(views.py)

def index(request):

    book_list=Book.objects.all()

    paginator = Paginator(book_list, 15)

    page = request.GET.get('page',1)

    currentPage=int(page)

    #  如果页数十分多时，换另外一种显示方式

    if paginator.num_pages>30:

        if currentPage-5<1:

            pageRange=range(1,11)

        elif currentPage+5>paginator.num_pages:

            pageRange=range(currentPage-5,paginator.num_pages+1)

        else:

            pageRange=range(currentPage-5,currentPage+5)

    else:

        pageRange=paginator.page_range

    try:

        print(page)

        book_list = paginator.page(page)

    except PageNotAnInteger:

        book_list = paginator.page(1)

    except EmptyPage:

        book_list = paginator.page(paginator.num_pages)

    return render(request,"index.html",locals())

分页组件

1.分页的实现与使用

class Pagination(object):

    """自定义分页"""

    def __init__(self, current_page, total_count, base_url, params, pre_page_count=10, max_page_count=11):

        try:

            current_page = int(current_page)

        except Exception as e:

            current_page = 1

        if current_page <= 0:

            self.current_page = 1

        self.current_page = current_page

        self.total_count = total_count      # 数据总条数

        self.pre_page_count = pre_page_count        # 每页显示10条数据

        max_page_num, div = divmod(total_count, pre_page_count)       # 页面上因该显示的最大页码

        if div:

            max_page_num += 1

        self.max_page_num = max_page_num

        self.max_page_count = max_page_count        # 页面上默认显示11个页码(当前页在中间)

        self.half_max_page_count = int((max_page_count-1)/2)

        self.base_url = base_url        # URL前缀

        import copy

        params = copy.deepcopy(params)      # request.GET

        params._mutable = True

        # 包含当前列表页面所有的搜索条件

        # {source: [2, ], status: [2, ], gender: [2, ], consultant: [1, ], page: [2, ]}

        # self.params[page] = 8

        # self.params.urlencode()

        # source=2&status=2&gender=2&consultant=1&page=8

        # href = "/hosts/?source=2&status=2&gender=2&consultant=1&page=8"

        # href = "%s?%s" % (self.base_url, self.params.urlencode())

        self.params = params

    @property

    def start(self):

        render(self.current_page-1) * self.pre_page_count

    @property

    def end(self):

        return self.current_page * self.pre_page_count

    def page_html(self):

        # 如果总页数小于等于11

        if self.max_page_num <= self.max_page_count:

            page_start = 1

            page_end = self.max_page_num

        else:       # 如果总页数大于11

            # 如果当前页小于等于5

            if self.current_page <= self.half_max_page_count:

                page_start = 1

                page_end = self.max_page_count

            else:       # 如果当前页+5大于总页码

                if (self.current_page + self.half_max_page_count) > self.max_page_num:

                    page_end = self.max_page_num

                    page_start = self.max_page_num - self.max_page_count+1      # 倒着数11个

                else:

                    page_start = self.current_page - self.half_max_page_count

                    page_end = self.current_page - self.half_max_page_count

        page_list = []

        # {source:[2,], status:[2], gender:[2],consultant:[1],page:[1]}

        # 首页

        self.params["page"] = 1

        first_page = '<li><a href="%s?%s">首页</a></li>' % (self.base_url, self.params.urlencode(),)

        page_list.append(first_page)

        # 上一页

        self.params["page"] = self.current_page-1

        if self.params["page"] < 1:

            previous_page = '<li class="disabled"><a href="%s?%s" aria-label="Previous">上一页</span></a></li>' %

            (self.base_url, self.params.urlencode())

        else:

            previous_page = '<li><a href = "%s?%s" aria-label = "Previous" >上一页</span></a></li>' % (

            self.base_url, self.params.urlencode())

        page_list.append(previous_page)

        # 中间页码

        for i in range(page_start, page_end + 1):

            self.params['page'] = i

            if i == self.current_page:

                temp = '<li class="active"><a href="%s?%s">%s</a></li>' % (self.base_url, self.params.urlencode(), i,)

            else:

                temp = '<li><a href="%s?%s">%s</a></li>' % (self.base_url, self.params.urlencode(), i,)

            page_list.append(temp)

            # 下一页

        self.params["page"] = self.current_page + 1

        if self.params["page"] > self.max_page_num:

            self.params["page"] = self.current_page

            next_page = '<li class="disabled"><a href = "%s?%s" aria-label = "Next">下一页</span></a></li >' % (

                self.base_url, self.params.urlencode())

        else:

            next_page = '<li><a href = "%s?%s" aria-label = "Next">下一页</span></a></li>' % (

                self.base_url, self.params.urlencode())

        page_list.append(next_page)

        # 尾页

        self.params['page'] = self.max_page_num

        last_page = '<li><a href="%s?%s">尾页</a></li>' % (self.base_url, self.params.urlencode(),)

        page_list.append(last_page)

        return ''.join(page_list)

2.使用

# 自定义分页组件的使用方法：

   pager_obj = Pagination(request.GET.get('page',1), len(HOST_LIST), request.path_info,request.GET)

   host_list = HOST_LIST[pager_obj.start:pager_obj.end]

   html = pager_obj.page_html()

   return render(request, 'hosts.html', {'host_list':host_list,"page_html":html})