45)django-分页实现

Django提供了一个新的类来帮助你管理分页数据，.它可以接收列表、元组或其它可迭代的对象。

一：常用方法

>>> from django.core.paginator import Paginator
>>> objects = ['john', 'paul', 'george', 'ringo']
>>> p = Paginator(objects, 2)

>>> p.count
4
>>> p.num_pages
2
>>> type(p.page_range)
<class 'range_iterator'>
>>> p.page_range
range(1, 3)

>>> page1 = p.page(1)
>>> page1
<Page 1 of 2>
>>> page1.object_list
['john', 'paul']

>>> page2 = p.page(2)
>>> page2.object_list
['george', 'ringo']
>>> page2.has_next()
False
>>> page2.has_previous()
True
>>> page2.has_other_pages()
True
>>> page2.next_page_number()
Traceback (most recent call last):
...
EmptyPage: That page contains no results
>>> page2.previous_page_number()
1
>>> page2.start_index() # The 1-based index of the first item on this page
3
>>> page2.end_index() # The 1-based index of the last item on this page
4

>>> p.page(0)
Traceback (most recent call last):
...
EmptyPage: That page number is less than 1
>>> p.page(3)
Traceback (most recent call last):
...
EmptyPage: That page contains no results

二：定义工具

　　定义工具，可供多个页面使用。

　　效果如下：

　　1）定义方法：pages.py

　

# -*- coding:utf-8 -*-
__author__ = 'lixiang'

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


def page(request,post_objects,page_number=20):
    """
    实现分页
    :param request:  view中request
    :param post_objects: 需要实现分页的对象（列表，queryset）
    :param page_number: #每页显示条数，默认20页
    :return:
    """
    #实例化结果集，    queryset转列表
    post_objects=list(post_objects)
    paginator = Paginator(post_objects, page_number) # Show 20 contacts per page

    #获取htmml中传递page值
    page = request.GET.get('page',1)
    try:
        #需要返回的值
        page_objs = paginator.page(page)
    except PageNotAnInteger:
        # 如果page不是整数，返回第1页
        page_objs = paginator.page(1)
    except EmptyPage:
        # 如果page超出最大值 ，只显示最后一页
        page_objs = paginator.page(paginator.num_pages)

    return page_objs

　　2）定义模板：paginator.html

<!--显示记录数-->
<div class="dataTables_info" id="editable_info" role="status" aria-live="polite">
    显示 {{ page_objs.start_index }} 至 {{ page_objs.end_index }} 条，共 {{ page_objs.paginator.count }} 条记录
</div>
<div class="text-right">
    {% load page_tag %}
    <ul class="pagination">
        <!--显示首页和上一页-->
        {% if page_objs.has_previous %}
            <li class="footable-page-arrow"><a data-page="first" href="?page=1">首页</a></li>
            <li class="footable-page-arrow"><a data-page="prev"
                                               href="?page={{ page_objs.previous_page_number }}">上一页</a></li>
        {% endif %}
        <!--显示页码，只通过自定义tag，实现只显示3个页码，-->
        {% for pg in page_objs.paginator.page_range %}
            <!--参数：当前页，循环页-->
            {% page_curent_show page_objs.number pg %}
        {% endfor %}

        <!--显示尾页和下一页-->
        {% if page_objs.has_next %}
            <li class="footable-page-arrow"><a data-page="next" href="?page={{ page_objs.next_page_number }}">下一页</a>
            </li>
            <li class="footable-page-arrow"><a data-page="last" href="?page={{ page_objs.paginator.num_pages }}">尾页</a>
            </li>
        {% endif %}
    </ul>
</div>

　　3）显示页码，通过自定义tag，实现只显示3个页码：page_tag.py

　　

# -*- coding:utf-8 -*-
__author__ = 'lixiang'
from django import template
from django.utils.html import format_html
register=template.Library()

@register.simple_tag
def page_curent_show(current_page,loop_page):
    """只显示3页码"""
    offset=abs(current_page-loop_page)
    if offset<3:
        if current_page==loop_page:
            #激活当前页
            page_ele='<li class="footable-page active"><a data-page="1" href="?page=%s">%s</a></li>' %(loop_page,loop_page)
        else:
            page_ele='<li class="footable-page"><a data-page="1" href="?page=%s">%s</a></li>' %(loop_page,loop_page)

        return format_html(page_ele)
    else:
        return ""

 　4）视图调用示例　

from utils.pages import page

def menu_list(request):
    menu_objs=models.Menu.objects.all()
    page_objs=page(request,menu_objs,2)
    return render(request, "juser/menu_list.html",{"page_objs":page_objs})

　5）页面嵌入分页

　　

            <table id="demo-foo-addrow"
                   class="table table-bordered table-hover toggle-circle footable-loaded footable default"
                   data-page-size="7">
                <thead>
                <tr>
                    <th data-sort-ignore="true" class="min-width footable-visible footable-first-column"></th>
                    <th data-sort-initial="true" data-toggle="true"
                        class="footable-visible footable-sortable footable-sorted">序号<span
                            class="footable-sort-indicator"></span></th>
                    <th class="footable-visible footable-sortable">菜单名<span
                            class="footable-sort-indicator"></span></th>
                    <th data-hide="phone, tablet" class="footable-visible footable-sortable">菜单位置<span
                            class="footable-sort-indicator"></span></th>
                    <th data-hide="phone, tablet" class="footable-visible footable-last-column footable-sortable">
                        操作<span
                            class="footable-sort-indicator"></span></th>
                </tr>
                </thead>

                <tbody>

                {% for menu_obj in page_objs %}
                    <tr class="footable-even" style="display: table-row;">
                        <td class="footable-visible footable-first-column">
                            <button class="demo-delete-row btn btn-danger btn-xs"><i class="demo-pli-cross"></i>
                            </button>
                        </td>
                        <td class="footable-visible"><span class="footable-toggle"></span>{{ forloop.counter }}</td>
                        <td class="footable-visible">{{ menu_obj.name }}</td>
                        <td class="footable-visible">{{ menu_obj.seq }}</td>
                        <td class="footable-visible">
                            <a><span class="label  label-success">查看</span></a>
                            <a><span class="label  label-dark">编辑</span></a>
                            <a><span class="label label-table label-danger">删除</span></a>
                        </td>
                    </tr>
                {% endfor %}
                </tbody>
                <tfoot>
                <tr>
                    <td colspan="7" class="footable-visible">
                        {% include "paginator.html" %}
                    </td>
                </tr>
                </tfoot>
            </table>
        </div>