Python Django 封装分页成通用的模块详解

            
class ShowPage(object):
  def __init__(self, page_num, total_count, url_prefix, per_page=10, max_page=11):
    '''
    :param page_num: 当前页码数
    :param total_count: 数据总数
    :param url_prefix: a 标签 href 的前缀
    :param per_page: 每页展示的数据数
    :param max_page: 页面上最多显示的页码数
    '''
    self.url_prefix = url_prefix
    self.max_page = max_page
    # 总共需要多少页码来显示
    total_page, m = divmod(total_count, per_page) 
    # 如果还有数据
    if m:
      total_page += 1
    self.total_page = total_page 
    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
      if page_num > self.total_page:
        page_num = self.total_page
      # 如果输入的页码数小于 1，则返回第一页
      if page_num < 1:
        page_num = 1
    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
    self.page_num = page_num 
    # 定义两个变量保存数据从哪儿取到哪儿
    self.data_start = (self.page_num - 1) * 10
    self.data_end = self.page_num * 10 
    # 页面上总共展示多少页码
    if self.total_page < self.max_page:
      self.max_page = self.total_page 
    half_max_page = self.max_page // 2 
    # 页面上展示的页码的开始页
    page_start = self.page_num - half_max_page
    # 页面上展示的页码的结束页
    page_end = self.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 = self.max_page
    # 如果当前页加一半比总页码还大
    if page_end >= self.total_page:
      page_end = self.total_page
      page_start = self.total_page - self.max_page + 1
    self.page_start = page_start
    self.page_end = page_end 
  @property
  def start(self):
    return self.data_start 
  @property
  def end(self):
    return self.data_end 
  def page_html(self):
    # 拼接 html 的分页代码
    html_list = [] 
    # 添加首页按钮
    html_list.append('
            

              
                首页
              
            
            '.format( self.url_prefix)) 
    # 如果是第一页，就没有上一页
    if self.page_num <= 1:
      html_list.append('
            

              
                
                  «
                
              
            
            '.format(self.page_num - 1))
    else:
      # 加一个上一页的标签
      html_list.append('
            

              
                
                  «
                
              
            
            '.format(self.url_prefix, self.page_num-1))
    # 展示的页码
    for i in range(self.page_start, self.page_end + 1):
      # 给当前页添加 active
      if i == self.page_num:
        tmp = '
            

              
                {1}
              
            
            '.format(self.url_prefix, i)
      else:
        tmp = '
            

              
                {1}
              
            
            '.format(self.url_prefix, i)
      html_list.append(tmp) 
    # 如果是最后一页，就没有下一页
    if self.page_num >= self.total_page:
      html_list.append('
            

              
                
                  »
                
              
            
            ')
    else:
      html_list.append(
        '
            

              
                
                  »
                
              
            
            '.format(self.url_prefix, self.page_num + 1)) 
    # 添加尾页按钮
    html_list.append('
            

              
                尾页
              
            
            '.format(self.url_prefix, self.total_page))
 
    page_html = "".join(html_list) # 拼接 html 的分页代码
    return page_html
          

            
from django.shortcuts import render
from app01 import models 
def book_list(request):
  # 从URL取参数
  page_num = request.GET.get("page")
  print(page_num, type(page_num)) 
  # 书籍总数
  total_count = models.Book.objects.all().count()
  # 导入显示页码的函数
  from utils.page import ShowPage
  page_obj = ShowPage(page_num, total_count, per_page=10, url_prefix="/book_list/", max_page=11, ) 
  ret = models.Book.objects.all()[page_obj.start:page_obj.end]
  print(ret) 
  page_html = page_obj.page_html()
  return render(request, "book_list.html", {"books": ret, "page_html": page_html})
          

            
            
            
            

              
                  
    {% for book in books %}
      
                  
                  
    {% endfor %}
 
    
                

                

                  

                    

                      序号
                    
                    

                      id
                    
                    

                      书名
                    
                  
                
                

                    

                      {{ forloop.counter }}
                    
                    

                      {{ book.id }}
                    
                    

                      {{ book.title }}