django自定义分页器
分页器原理
自定义分页器需要掌握的基本思路
1.queryset对象是直接切片操作的
2.用户要访问的页码通过url后面携带参数传给后端
url?page=1
current_page = request.GET.get('page', 1)
# 获取到的数据都是字符串类型 你需要注意类型转换
3.后端自己规定每页展示多少条数据
per_page_num = 10
4.切片的起始位置和终止位置
start_page = （current_page - 1）* per_page_num
end_page = current_page * per_page_num
5.当前数据的总条数
all_count = book_queryset.count()
6.利用python内置函数divmod()确定一共需要多少页展示全部数据
page_count, more = divmod(all_count, per_page_num)
if more:
page_count += 1
7.前端模版语法是没有range功能的
# 前端代码不一定非要在前端书写 也可以在后端生成传递给页面
8.针对需要展示的页码需要你自己规划好到底展示多少个页码
# 一般情况下页码的个数设计都是奇数(符合审美标准) 11个页码
当前页减5
当前页加6
你可以给标签价样式从而让选中的页码高亮显示
9.针对页码小于6的情况，你需要做处理，不能再减
前端页面
<nav aria-label="Page navigation">
<ul class="pagination">
<li>
<a href="#" aria-label="Previous">
<span aria-hidden="true">«</span>
</a>
</li>
{{ page_html|safe }}
<li>
<a href="#" aria-label="Next">
<span aria-hidden="true">»</span>
</a>
</li>
</ul>
</nav>
后端分页逻辑
def page(request):
current_page = request.GET.get('page', 1)
try:
current_page = int(current_page)
except Exception:
current_page = 1
counts_per_page = 5
start_index = (current_page - 1) * counts_per_page
end_index = current_page * counts_per_page
total_user = models.User.objects.count()
total_page_counts, more = divmod(total_user, counts_per_page)
if more:
total_page_counts += 1
if current_page < 6:
page_start = 6
else:
page_start = current_page
page_html = ''
for i in range(page_start - 5, current_page + 6):
if i== int(current_page):
page_html += f'<li class="active"><a href="?page={i}">{i}</a></li>'
else:
page_html += f'<li class=""><a href="?page={i}">{i}</a></li>'
user_list = models.User.objects.all()[start_index:end_index]
return render(request, 'page.html', locals())
自定义分页器
当我们需要使用到非django内置的第三方功能或者组件代码的时候，一般情况下会创建一个名为
utils文件夹。文件夹内存放第三方组件代码，
utils可以在每个应用下创建也可以在项目根路径下，具体结合实际情况。
我们自定义的分页器是基于bootstrap样式来的，所以使用时需要提前导入bootstrap。
自定义分页器代码：utils/mypagination.py
class Pagination(object):
def __init__(self, current_page, all_count, per_page_num=10, pager_count=11):
"""
封装分页相关数据
:param current_page: 当前页码，str
:param all_count: 数据库中的数据总条数
:param per_page_num: 每页显示的数据条数
:param pager_count: 最多显示的页码个数
"""
try:
current_page = int(current_page)
except Exception as e:
current_page = 1
if current_page < 1:
current_page = 1
self.current_page = current_page
self.all_count = all_count
self.per_page_num = per_page_num
# 总页码
all_pager, tmp = divmod(all_count, per_page_num)
if tmp:
all_pager += 1
self.all_pager = all_pager
self.pager_count = pager_count
self.pager_count_half = int((pager_count - 1) / 2)
@property
def start(self):
return (self.current_page - 1) * self.per_page_num
@property
def end(self):
return self.current_page * self.per_page_num
def page_html(self):
# 如果总页码 < 11个：
if self.all_pager <= self.pager_count:
pager_start = 1
pager_end = self.all_pager + 1
# 总页码 > 11
else:
# 当前页如果<=页面上最多显示11/2个页码
if self.current_page <= self.pager_count_half:
pager_start = 1
pager_end = self.pager_count + 1
# 当前页大于5
else:
# 页码翻到最后
if (self.current_page + self.pager_count_half) > self.all_pager:
pager_end = self.all_pager + 1
pager_start = self.all_pager - self.pager_count + 1
else:
pager_start = self.current_page - self.pager_count_half
pager_end = self.current_page + self.pager_count_half + 1
page_html_list = []
# 添加前面的nav和ul标签
page_html_list.append('''
<nav aria-label='Page navigation>'
<ul class='pagination'>
''')
first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
page_html_list.append(first_page)
if self.current_page <= 1:
prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
else:
prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)
page_html_list.append(prev_page)
for i in range(pager_start, pager_end):
if i == self.current_page:
temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
else:
temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
page_html_list.append(temp)
if self.current_page >= self.all_pager:
next_page = '<li class="disabled"><a href="#">下一页</a></li>'
else:
next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
page_html_list.append(next_page)
last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
page_html_list.append(last_page)
# 尾部添加标签
page_html_list.append('''
</nav>
</ul>
''')
return ''.join(page_html_list)
使用方法：
-
拷贝上述代码存放在制定文件夹内，如
utils -
后端引入该文件中的Pagination类并实例化对象
def page(request):
book_queryset = models.Book.objects.all()
current_page = request.GET.get('page',1)
all_count = book_queryset.count()
# 1 传值实例化对象
page_obj = Pagination(current_page=current_page, all_count=all_count)
# 2 直接对总数据进行切片操作
page_queryset = book_queryset[page_obj.start:page_obj.end]
# 3 将page_queryset传递到页面，替换之前的book_queryset
return render(request, 'page.html', locals())
- 前端页面，因为直接在后端书写了bootstrap的分页样式代码，前端直接safe显示该html即可。
{#数据展示部分#}
{% for book_obj in page_queryset %}
<p>{{ book_obj.title }}</p>
{% endfor %}
{#分页器#}
{{ page_obj.page_html|safe }}
django分页器组件(参考)
views.py
from django.shortcuts import render,HttpResponse
# Create your views here.
from app01.models import *
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger
def index(request):
'''
分页器的使用:
book_list=Book.objects.all()
paginator = Paginator(book_list, 10)
print("count:",paginator.count) #数据总数
print("num_pages",paginator.num_pages) #总页数
print("page_range",paginator.page_range) #页码的列表
page1=paginator.page(1) #第1页的page对象
for i in page1: #遍历第1页的所有数据对象
print(i)
print(page1.object_list) #第1页的所有数据
page2=paginator.page(2)
print(page2.has_next()) #是否有下一页
print(page2.next_page_number()) #下一页的页码
print(page2.has_previous()) #是否有上一页
print(page2.previous_page_number()) #上一页的页码
# 抛错
#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)
currentPage=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,"currentPage":currentPage})
index.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>
扩展
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>11:
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())
