Python Django 封裝分頁成通用的模塊詳解

class ShowPage(object):
  def __init__(self, page_num, total_count, url_prefix, per_page=10, max_page=11):
    '''
    :param page_num: 當(dāng)前頁碼數(shù)
    :param total_count: 數(shù)據(jù)總數(shù)
    :param url_prefix: a 標(biāo)簽 href 的前綴
    :param per_page: 每頁展示的數(shù)據(jù)數(shù)
    :param max_page: 頁面上最多顯示的頁碼數(shù)
    '''
    self.url_prefix = url_prefix
    self.max_page = max_page
    # 總共需要多少頁碼來顯示
    total_page, m = divmod(total_count, per_page) 
    # 如果還有數(shù)據(jù)
    if m:
      total_page += 1
    self.total_page = total_page 
    try:
      page_num = int(page_num)
      # 如果輸入的頁碼數(shù)超過了最大的頁碼數(shù)，默認(rèn)返回最后一頁
      if page_num > self.total_page:
        page_num = self.total_page
      # 如果輸入的頁碼數(shù)小于 1，則返回第一頁
      if page_num < 1:
        page_num = 1
    except Exception as e:
      # 當(dāng)輸入的頁碼不是正經(jīng)數(shù)字的時候 默認(rèn)返回第一頁的數(shù)據(jù)
      page_num = 1
    self.page_num = page_num 
    # 定義兩個變量保存數(shù)據(jù)從哪兒取到哪兒
    self.data_start = (self.page_num - 1) * 10
    self.data_end = self.page_num * 10 
    # 頁面上總共展示多少頁碼
    if self.total_page < self.max_page:
      self.max_page = self.total_page 
    half_max_page = self.max_page // 2 
    # 頁面上展示的頁碼的開始頁
    page_start = self.page_num - half_max_page
    # 頁面上展示的頁碼的結(jié)束頁
    page_end = self.page_num + half_max_page
    # 如果當(dāng)前頁減一半比 1 還小
    if page_start <= 1:
      page_start = 1
      page_end = self.max_page
    # 如果當(dāng)前頁加一半比總頁碼還大
    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 的分頁代碼
    html_list = [] 
    # 添加首頁按鈕
    html_list.append('<li><a href="{}?page=1" rel="external nofollow" >首頁</a></li>'.format( self.url_prefix)) 
    # 如果是第一頁，就沒有上一頁
    if self.page_num <= 1:
      html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(self.page_num - 1))
    else:
      # 加一個上一頁的標(biāo)簽
      html_list.append('<li><a href="{}?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(self.url_prefix, self.page_num-1))
    # 展示的頁碼
    for i in range(self.page_start, self.page_end + 1):
      # 給當(dāng)前頁添加 active
      if i == self.page_num:
        tmp = '<li class="active"><a href="{0}?page={1}" rel="external nofollow" rel="external nofollow" >{1}</a></li>'.format(self.url_prefix, i)
      else:
        tmp = '<li><a href="{0}?page={1}" rel="external nofollow" rel="external nofollow" >{1}</a></li>'.format(self.url_prefix, i)
      html_list.append(tmp) 
    # 如果是最后一頁，就沒有下一頁
    if self.page_num >= self.total_page:
      html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>')
    else:
      html_list.append(
        '<li><a href="{}?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>'.format(self.url_prefix, self.page_num + 1)) 
    # 添加尾頁按鈕
    html_list.append('<li><a href="{}?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" >尾頁</a></li>'.format(self.url_prefix, self.total_page))
 
    page_html = "".join(html_list) # 拼接 html 的分頁代碼
    return page_html

from django.shortcuts import render
from app01 import models 
def book_list(request):
  # 從URL取參數(shù)
  page_num = request.GET.get("page")
  print(page_num, type(page_num)) 
  # 書籍總數(shù)
  total_count = models.Book.objects.all().count()
  # 導(dǎo)入顯示頁碼的函數(shù)
  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})

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>書籍列表</title>
  <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css" rel="external nofollow" >
</head>
<body>
 
<div class="container"> 
  <table class="table table-bordered">
    <thead>
    <tr>
      <th>序號</th>
      <th>id</th>
      <th>書名</th>
    </tr>
    </thead>
    <tbody>
    {% for book in books %}
      <tr>
        <td>{{ forloop.counter }}</td>
        <td>{{ book.id }}</td>
        <td>{{ book.title }}</td>
      </tr>
    {% endfor %}
 
    </tbody>
  </table> 
  <nav aria-label="Page navigation">
    <ul class="pagination">
      <li>
        {{ page_html|safe }}
      </li>
    </ul>
  </nav> 
</div>
</body>
</html>