Django之分页器

分页器推导

上面批量数据操作会让所有数据全部展示到一张页面上，基于上面的数据展示进行分页处理。每页展示几条

view.py

  1. from django.shortcuts import render, HttpResponse, redirect
  2. from app01 import models
  5. def index(request):
  6.     data_queryset = models.Book.objects.all()
  8.     current_page_num = request.GET.get('page')
  9.     try:
  11.         current_page_num = int(current_page_num)
  13.     except Exception:
  14.         current_page_num = 1
  16.     if not current_page_num:
  17.         current_page_num = 1
  18.     # 每页展示几条数据
  19.     per_page_num = 10
  20.     # 起始位置
  21.     start_num = (current_page_num - 1) * per_page_num
  22.     # 终止位置
  23.     stop_num = current_page_num * per_page_num
  25.     book_queryset = data_queryset[start_num:stop_num]  # 顾头不顾尾
  26.     """
  27.     per_page_num = 10
  28.     current_page_num            start_num           stop_num
  29.             1                       0                   10
  30.             2                       10                  20
  31.             3                       20                  30
  33.     per_page_num = 5
  34.     current_page_num            start_num           stop_num
  35.             1                       0                   5
  36.             2                       5                   10
  37.             3                       10                  15
  39.     规律: 
  40.         start_num = (current_page_num-1) * per_page_num
  41.         end_num = current_page_num * per_page_num    
  42.     """
  44.     # 前端渲染的页面数量
  45.     all_count = data_queryset.count()
  46.     # 内置方法之 divmod()
  47.     page_num, more = divmod(all_count, per_page_num)
  48.     if more:
  49.         page_num += 1
  50.     html = ''
  51.     high_light_pag = current_page_num
  52.     if current_page_num < 6:
  53.         current_page_num = 6
  54.     for i in range(current_page_num - 5, current_page_num + 6):
  55.         if high_light_pag == i:
  56.             html += '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i)
  57.         else:
  58.             html += '<li><a href="?page=%s">%s</a></li>' % (i, i)
  60.     return render(request, 'index.html', locals())

index.html

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6. </head>
  7. <body>
  8. <div class="text-center">
  9.     {% for book_obj in book_queryset %}
  10.         <p>{{ book_obj.title }}</p>
  11.     {% endfor %}
  12.     <nav aria-label="Page navigation">
  13.         <ul class="pagination">
  14.             <li>
  15.                 <a href="#" aria-label="Previous">
  16.                     <span aria-hidden="true">&laquo;</span>
  17.                 </a>
  18.             </li>
  19.             {{ html|safe }}
  20.             <li>
  21.                 <a href="#" aria-label="Next">
  22.                     <span aria-hidden="true">&raquo;</span>
  23.                 </a>
  24.             </li>
  25.         </ul>
  26.     </nav>
  27. </div>
  30. </body>
  31. </html>

分页器封装模块

创建一个utils目录，写好的封装摸块的放在这个位置方便引用

my_page.py

  1. class Pagination(object):
  2.     def __init__(self, current_page, all_count, per_page_num=10, pager_count=11):
  3.         """
  4.         封装分页相关数据
  5.         :param current_page: 当前页
  6.         :param all_count:    数据库中的数据总条数
  7.         :param per_page_num: 每页显示的数据条数
  8.         :param pager_count:  最多显示的页码个数
  9.         """
  10.         try:
  11.             current_page = int(current_page)
  12.         except Exception as e:
  13.             current_page = 1
  15.         if current_page < 1:
  16.             current_page = 1
  18.         self.current_page = current_page
  20.         self.all_count = all_count
  21.         self.per_page_num = per_page_num
  23.         # 总页码
  24.         all_pager, tmp = divmod(all_count, per_page_num)
  25.         if tmp:
  26.             all_pager += 1
  27.         self.all_pager = all_pager
  29.         self.pager_count = pager_count
  30.         self.pager_count_half = int((pager_count - 1) / 2)
  32.     @property
  33.     def start(self):
  34.         return (self.current_page - 1) * self.per_page_num
  36.     @property
  37.     def end(self):
  38.         return self.current_page * self.per_page_num
  40.     def page_html(self):
  41.         # 如果总页码 < 11个：
  42.         if self.all_pager <= self.pager_count:
  43.             pager_start = 1
  44.             pager_end = self.all_pager + 1
  45.         # 总页码  > 11
  46.         else:
  47.             # 当前页如果<=页面上最多显示11/2个页码
  48.             if self.current_page <= self.pager_count_half:
  49.                 pager_start = 1
  50.                 pager_end = self.pager_count + 1
  52.             # 当前页大于5
  53.             else:
  54.                 # 页码翻到最后
  55.                 if (self.current_page + self.pager_count_half) > self.all_pager:
  56.                     pager_end = self.all_pager + 1
  57.                     pager_start = self.all_pager - self.pager_count + 1
  58.                 else:
  59.                     pager_start = self.current_page - self.pager_count_half
  60.                     pager_end = self.current_page + self.pager_count_half + 1
  62.         page_html_list = []
  63.         # 添加前面的nav和ul标签
  64.         page_html_list.append('''
  65.                     <nav aria-label='Page navigation>'
  66.                     <ul class='pagination'>
  67.                 ''')
  68.         first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
  69.         page_html_list.append(first_page)
  71.         if self.current_page <= 1:
  72.             prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
  73.         else:
  74.             prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)
  76.         page_html_list.append(prev_page)
  78.         for i in range(pager_start, pager_end):
  79.             if i == self.current_page:
  80.                 temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
  81.             else:
  82.                 temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
  83.             page_html_list.append(temp)
  85.         if self.current_page >= self.all_pager:
  86.             next_page = '<li class="disabled"><a href="#">下一页</a></li>'
  87.         else:
  88.             next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
  89.         page_html_list.append(next_page)
  91.         last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
  92.         page_html_list.append(last_page)
  93.         # 尾部添加标签
  94.         page_html_list.append('''
  95.                                            </nav>
  96.                                            </ul>
  97.                                        ''')
  98.         return ''.join(page_html_list)

view.py

  1. from django.shortcuts import render
  2. from app01 import models
  5. def index(request):
  6.     from utils import my_page
  7.     book_queryset = models.Book.objects.all()
  8.     all_count = book_queryset.count()
  9.     # 产生分页器对象
  10.     page_obj = my_page.Pagination(current_page=request.GET.get('page'), all_count=all_count)
  11.     # 产生分页数据对象
  12.     page_queryset = book_queryset[page_obj.start:page_obj.end]
  13.     return render(request, 'index.html', locals())

index.html

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6. </head>
  7. <body>
  8. <div class="text-center">
  9.     {% for book_obj in page_queryset %}
  10.         <p>{{ book_obj.title }}</p>
  11.     {% endfor %}
  12.     {{ page_obj.page_html|safe}}
  13. </div>
  14. </body>
  15. </html>