007 分页函数

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
: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

用法:
queryset = model.objects.all()
page_obj = Pagination(current_page,all_count)
page_data = queryset[page_obj.start:page_obj.end]
获取数据用page_data而不再使用原始的queryset
获取前端分页样式用page_obj.page_html
"""
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>'

''')
first_page = '
• 首页
' % (1)
page_html_list.append(first_page)

if self.current_page <= 1:
prev_page = '

• 上一页
'
else:
prev_page = '
• 上一页
' % (self.current_page - 1,)

page_html_list.append(prev_page)

for i in range(pager_start, pager_end):
if i == self.current_page:
temp = '

• %s
' % (i, i,)
else:
temp = '
• %s
' % (i, i,)
page_html_list.append(temp)

if self.current_page >= self.all_pager:
next_page = '

• 下一页
'
else:
next_page = '
• 下一页
' % (self.current_page + 1,)
page_html_list.append(next_page)

last_page = '

• 尾页
' % (self.all_pager,)
page_html_list.append(last_page)
# 尾部添加标签
page_html_list.append('''

''')
return ''.join(page_html_list)