djangodocs

Django 2.1
简体中文
Documentation contents

分页

Django provides a few classes that help you manage paginated data -- that is, data that's split across several pages, with "Previous/Next" links. These classes live in django/core/paginator.py.

例如

Give Paginator a list of objects, plus the number of items you'd like to have on each page, and it gives you methods for accessing the items for each page:

Code
>>> 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

在视图中使用 Paginator

Here's a slightly more complex example using Paginator in a view to paginate a queryset. We give both the view and the accompanying template to show how you can display the results. This example assumes you have a Contacts model that has already been imported.

The view function looks like this:

Code
from django.core.paginator import Paginator
from django.shortcuts import render

def listing(request):
    contact_list = Contacts.objects.all()
    paginator = Paginator(contact_list, 25) # Show 25 contacts per page

    page = request.GET.get('page')
    contacts = paginator.get_page(page)
    return render(request, 'list.html', {'contacts': contacts})

In the template list.html, you'll want to include navigation between pages along with any interesting information from the objects themselves:

Django template
{% for contact in contacts %}
    {# Each "contact" is a Contact model object. #}
    {{ contact.full_name|upper }}<br>
    ...
{% endfor %}

<div class="pagination">
    <span class="step-links">
        {% if contacts.has_previous %}
            <a href="?page=1">&laquo; first</a>
            <a href="?page={{ contacts.previous_page_number }}">previous</a>
        {% endif %}

        <span class="current">
            Page {{ contacts.number }} of {{ contacts.paginator.num_pages }}.
        </span>

        {% if contacts.has_next %}
            <a href="?page={{ contacts.next_page_number }}">next</a>
            <a href="?page={{ contacts.paginator.num_pages }}">last &raquo;</a>
        {% endif %}
    </span>
</div>

Paginator 对象

Paginator 类的构造方法是:

class Paginator(object_list, per_page, orphans=0, allow_empty_first_page=True)

必选参数

object_list

A list, tuple, QuerySet, or other sliceable object with a count() or __len__() method. For consistent pagination, QuerySets should be ordered, e.g. with an order_by() clause or with a default ordering on the model.

per_page

The maximum number of items to include on a page, not including orphans (see the orphans optional argument below).

可选参数

orphans

Use this when you don't want to have a last page with very few items. If the last page would normally have a number of items less than or equal to orphans, then those items will be added to the previous page (which becomes the last page) instead of leaving the items on a page by themselves. For example, with 23 items, per_page=10, and orphans=3, there will be two pages; the first page with 10 items and the second (and last) page with 13 items. orphans defaults to zero, which means pages are never combined and the last page may have one item.

allow_empty_first_page

Whether or not the first page is allowed to be empty. If False and object_list is empty, then an EmptyPage error will be raised.

方法

Paginator.get_page(number)

Returns a Page object with the given 1-based index, while also handling out of range and invalid page numbers.

If the page isn't a number, it returns the first page. If the page number is negative or greater than the number of pages, it returns the last page.

It raises an exception (EmptyPage) only if you specify Paginator(..., allow_empty_first_page=False) and the object_list is empty.

Paginator.page(number)

Returns a Page object with the given 1-based index. Raises InvalidPage if the given page number doesn't exist.

属性

Paginator.count

The total number of objects, across all pages.

Paginator.num_pages

The total number of pages.

Paginator.page_range

A 1-based range iterator of page numbers, e.g. yielding [1, 2, 3, 4].

InvalidPage exceptions

exception InvalidPage

当paginator对象试图访问无效页码时引发异常的基类。

The Paginator.page() method raises an exception if the requested page is invalid (i.e., not an integer) or contains no objects. Generally, it's enough to catch the InvalidPage exception, but if you'd like more granularity, you can catch either of the following exceptions:

exception PageNotAnInteger

Raised when page() is given a value that isn't an integer.

exception EmptyPage

Raised when page() is given a valid value but no objects exist on that page.

Both of the exceptions are subclasses of InvalidPage, so you can handle them both with a simple except InvalidPage.

Page objects

你通常不会手动实例化Page对象 - 你会使用方法Paginator.page()。

class Page(object_list, number, paginator)

A page acts like a sequence of Page.object_list when using len() or iterating it directly.

方法

Page.has_next()

Returns True if there's a next page.

Page.has_previous()

Returns True if there's a previous page.

Page.has_other_pages()

Returns True if there's a next or previous page.

Page.next_page_number()

Returns the next page number. Raises InvalidPage if next page doesn't exist.

Page.previous_page_number()

Returns the previous page number. Raises InvalidPage if previous page doesn't exist.

Page.start_index()

Returns the 1-based index of the first object on the page, relative to all of the objects in the paginator's list. For example, when paginating a list of 5 objects with 2 objects per page, the second page's start_index() would return 3.

Page.end_index()

Returns the 1-based index of the last object on the page, relative to all of the objects in the paginator's list. For example, when paginating a list of 5 objects with 2 objects per page, the second page's end_index() would return 4.

属性

Page.object_list

此页上的对象列表。

Page.number

此页的基于 1 的页码。

Page.paginator

关联的 Paginator 对象。

This page as Markdown JSON

Edit this page on GitHub Official version