Python--day71--分页功能

分页功能代码：

 from django.shortcuts import render

 # Create your views here.

 from app01 import models

 def books(request):
     #从URL取参数
     page_num = request.GET.get("page")
     print(page_num,type(page_num))
     # 每一页显示多少条数据
     per_page = 10
     # 总数据是多少
     total_count = models.Book.objects.all().count()
     # 总共需要多少页码来展示
     total_page, m = divmod(total_count, per_page)
     if m:
         total_page += 1
     try:
         page_num = int(page_num)
         # 如果输入的页码数超过了最大的页码数，默认返回最后一页的数据
         if page_num > total_page:
             page_num = total_page
     except Exception as e:
         #当输入的页码不是正经数字的时候，默认返回第一页的数据
         page_num = 1

     #定义两个变量保存数据从哪儿取到哪儿
     data_start = (page_num-1)*10
     data_end = page_num*10

     #页面总共展示多少页码
     max_page = 11
     if total_page < max_page:
         max_page = total_page

     half_max_page = max_page // 2
     #页面上展示的页码从哪儿开始
     page_start = page_num - half_max_page
     #页面上展示的页码到哪儿结束
     page_end = page_num + half_max_page
     #如果当前页减一半，比1还小
     if page_start <= 1:
         page_start = 1
         page_end = max_page

     #如果当前页加一半比总页码数还大
     if page_end >= total_page:
         page_end = total_page
         page_start = total_page - max_page +1

     all_book = models.Book.objects.all()[data_start:data_end]

     #自己拼接分页的HTML代码
     html_str_list = []
     #加上第一页
     html_str_list.append('<li><a href="/books/?page=1">首页</a></li>')
     #加上一个上一页的标签
     #判断，如果是第一页就没有上一页了
     if page_num <= 1:
         html_str_list.append(' <li class="disabled"><a href="#" ><span aria-hidden="true">&laquo;</span></a><li>')
     else:
         #加上一个上一页的功能
         html_str_list.append(' <li><a href="/books/?page={}" ><span aria-hidden="true">&laquo;</span></a><li>'.format(page_num-1))

     for i in range(page_start,page_end +1):
         #如果是当前页就加一个active样式类
         # if i == page_num:
         #     tmp = '<li class="active"><a href="/books/?page={0}">{0}</a></li>'.format(i)
         # else:
         if i == page_num:
             tmp = '<li class="active"><a href="/books/?page={0}">{0}</a></li>'.format(i)
         else:
             tmp = '<li><a href="/books/?page={0}">{0}</a></li>'.format(i)

         html_str_list.append(tmp)

     #加上一个下一页的标签
     #判断，如果是最后一页，就没有下一页
     if page_num >= total_page:
         html_str_list.append('<li class="disabled"><a href="#" aria-label="Next"><span aria-hidden="true">&raquo;</span></a><li>')
     else:
         html_str_list.append('<li><a href="/books/?page={}" aria-label="Next"><span aria-hidden="true">&raquo;</span></a><li>'.format(page_num+1))
     #加上最后一页
     html_str_list.append('<li><a href="/books/?page={0}">末页</a></li>'.format(total_page))

     page_html = "".join(html_str_list)

     return render(request,'books.html',{'books':all_book,"page_html":page_html})