Python Django 添加首页尾页上一页下一页代码实例

编程语言 2020-03-15 14:01:01 阅读次数: 0

这篇文章主要介绍了Python Django 添加首页尾页上一页下一页代码实例,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
添加首页和尾页：
views.py：

from django.shortcuts import render
from app01 import models
def book_list(request):

从 URL 中取参数

page_num = request.GET.get(“page”)
print(page_num, type(page_num))
page_num = int(page_num)

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

书籍总数

total_count = models.Book.objects.all().count()

每一页显示多少条数据

per_page = 10

总共需要多少页码来显示

total_page, m = divmod(total_count, per_page)

页面上最多展示的页码

max_page = 11
half_max_page = max_page // 2

页面上展示的页码的开始页

page_start = page_num - half_max_page

页面上展示的页码的结束页

page_end = page_num + half_max_page

如果当前页减一半比 1 小

if page_start <= 1:
page_start = 1
page_end = max_page

如果当前页加一半比总页码还大

if page_end > total_page:
page_end = total_page
page_start = total_page - max_page + 1

如果还有数据

if m:
total_page += 1
all_book = models.Book.objects.all()[data_start:data_end]

拼接 html 的分页代码

html_list = []

添加首页按钮

html_list.append(‘

  • 首页
    • ’)

    展示的页码

    for i in range(page_start, page_end + 1):
    tmp = ‘

  • {0}
    • ’.format(i)
    html_list.append(tmp)

    添加尾页按钮

    html_list.append(‘

  • 尾页
    • ’.format(total_page))
    page_html = “”.join(html_list) # 拼接 html 的分页代码
    return render(request, “book_list.html”, {“books”: all_book, “page_html”: page_html}) 

    book_list.html：<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>书籍列表</title>
  <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" >
</head>
<body> 
<div class="container"> 
  <table class="table table-bordered">
    <thead>
    <tr>
      <th>序号</th>
      <th>id</th>
      <th>书名</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>

    运行结果：在这里插入图片描述
    添加上一页、下一页：

    views.py：

    from django.shortcuts import render
from app01 import models 
def book_list(request):
  # 从 URL 中取参数
  page_num = request.GET.get("page")
  print(page_num, type(page_num))
  page_num = int(page_num) 
  # 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
  # 书籍总数
  total_count = models.Book.objects.all().count() 
  # 每一页显示多少条数据
  per_page = 10
  # 总共需要多少页码来显示
  total_page, m = divmod(total_count, per_page) 
  # 页面上最多展示的页码
  max_page = 11
  half_max_page = max_page // 2
  # 页面上展示的页码的开始页
  page_start = page_num - half_max_page
  # 页面上展示的页码的结束页
  page_end = page_num + half_max_page 
  # 如果当前页减一半比 1 小
  if page_start <= 1:
    page_start = 1
    page_end = max_page
  # 如果当前页加一半比总页码还大
  if page_end > total_page:
    page_end = total_page
    page_start = total_page - max_page + 1
  # 如果还有数据
  if m:
    total_page += 1
  all_book = models.Book.objects.all()[data_start:data_end] 
  # 拼接 html 的分页代码
  html_list = [] 
  # 添加首页按钮
  html_list.append('<li><a href="/book_list/?page=1" rel="external nofollow" rel="external nofollow" rel="external nofollow" >首页</a></li>') 
  # 如果是第一页，就没有上一页
  if page_num <= 1:
    html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(page_num-1))
  else:
    # 加一个上一页的标签
    html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(page_num-1)) 
  # 展示的页码
  for i in range(page_start, page_end + 1):
    # 给当前页添加 active
    if i == page_num:
      tmp = '<li class="active"><a href="/book_list/?page={0}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >{0}</a></li>'.format(i)
    else:
      tmp = '<li><a href="/book_list/?page={0}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >{0}</a></li>'.format(i)
    html_list.append(tmp) 
  # 如果是最后一页，就没有下一页
  if page_num >= total_page:
    html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>')
  else:
    html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>'.format(page_num+1)) 
  # 添加尾页按钮
  html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >尾页</a></li>'.format(total_page))
  
  page_html = "".join(html_list) # 拼接 html 的分页代码
  return render(request, "book_list.html", {"books": all_book, "page_html": page_html})

    book_list.html：

    <!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>书籍列表</title>
  <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" >
</head>
<body> 
<div class="container"> 
  <table class="table table-bordered">
    <thead>
    <tr>
      <th>序号</th>
      <th>id</th>
      <th>书名</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>

    运行结果：在这里插入图片描述
    后续改进：

    处理用户传给 url 的 page 参数异常的值的情况

    例如：

    访问，http://127.0.0.1:8888/book_list/?page=a

    访问，http://127.0.0.1:8888/book_list/?page=-1

    都会出错

    改进：

    from django.shortcuts import render
from app01 import models
def book_list(request):
  # 从 URL 中取参数
  page_num = request.GET.get("page")
  print(page_num, type(page_num)) # page_num 为 str 类型
  # 书籍总数
  total_count = models.Book.objects.all().count() 
  # 每一页显示多少条数据
  per_page = 10
  # 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
  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 > total_page:
      page_num = 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
  # 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
  # 页面上最多展示的页码
  max_page = 11
  half_max_page = max_page // 2
  # 页面上展示的页码的开始页
  page_start = page_num - half_max_page
  # 页面上展示的页码的结束页
  page_end = page_num + half_max_page 
  # 如果当前页减一半比 1 小
  if page_start <= 1:
    page_start = 1
    page_end = max_page
  # 如果当前页加一半比总页码还大
  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] 
  # 拼接 html 的分页代码
  html_list = [] 
  # 添加首页按钮
  html_list.append('<li><a href="/book_list/?page=1" rel="external nofollow" rel="external nofollow" rel="external nofollow" >首页</a></li>') 
  # 如果是第一页，就没有上一页
  if page_num <= 1:
    html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(page_num-1))
  else:
    # 加一个上一页的标签
    html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(page_num-1))
   # 展示的页码
  for i in range(page_start, page_end + 1):
    # 给当前页添加 active
    if i == page_num:
      tmp = '<li class="active"><a href="/book_list/?page={0}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >{0}</a></li>'.format(i)
    else:
      tmp = '<li><a href="/book_list/?page={0}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >{0}</a></li>'.format(i)
    html_list.append(tmp) 
  # 如果是最后一页，就没有下一页
  if page_num >= total_page:
    html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>')
  else:
    html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>'.format(page_num+1)) 
  # 添加尾页按钮
  html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >尾页</a></li>'.format(total_page))
  
  page_html = "".join(html_list) # 拼接 html 的分页代码
  return render(request, "book_list.html", {"books": all_book, "page_html": page_html})

    如果数据库中的数据数少于 max_page，则会显示负数的页数

    例如数据库中只有 21 条数据：在这里插入图片描述
    改进：

    from django.shortcuts import render
from app01 import models
def book_list(request):
  # 从 URL 中取参数
  page_num = request.GET.get("page")
  print(page_num, type(page_num)) # page_num 为 str 类型 
  # 书籍总数
  total_count = models.Book.objects.all().count() 
  # 每一页显示多少条数据
  per_page = 10
  # 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
  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 > total_page:
      page_num = 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
  # 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
  # 页面上最多展示的页码
  max_page = 11
  # 如果总页码数小于页面上最多展示的页码
  if total_page < max_page:
    max_page = total_page
  half_max_page = max_page // 2
  # 页面上展示的页码的开始页
  page_start = page_num - half_max_page
  # 页面上展示的页码的结束页
  page_end = page_num + half_max_page 
  # 如果当前页减一半比 1 小
  if page_start <= 1:
    page_start = 1
    page_end = max_page
  # 如果当前页加一半比总页码还大
  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] 
  # 拼接 html 的分页代码
  html_list = [] 
  # 添加首页按钮
  html_list.append('<li><a href="/book_list/?page=1" rel="external nofollow" rel="external nofollow" rel="external nofollow" >首页</a></li>') 
  # 如果是第一页，就没有上一页
  if page_num <= 1:
    html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(page_num-1))
  else:
    # 加一个上一页的标签
    html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">«</span></a></li>'.format(page_num-1))
  # 展示的页码
  for i in range(page_start, page_end + 1):
    # 给当前页添加 active
    if i == page_num:
      tmp = '<li class="active"><a href="/book_list/?page={0}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >{0}</a></li>'.format(i)
    else:
      tmp = '<li><a href="/book_list/?page={0}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >{0}</a></li>'.format(i)
    html_list.append(tmp) 
  # 如果是最后一页，就没有下一页
  if page_num >= total_page:
    html_list.append('<li class="disabled"><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>')
  else:
    html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ><span aria-hidden="true">»</span></a></li>'.format(page_num+1)) 
  # 添加尾页按钮
  html_list.append('<li><a href="/book_list/?page={}" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >尾页</a></li>'.format(total_page)) 
  page_html = "".join(html_list) # 拼接 html 的分页代码
  return render(request, "book_list.html", {"books": all_book, "page_html": page_html})

    运行结果：
    在这里插入图片描述
    最后给大家推荐一个资源很全的python学习聚集地，[点击进入]，这里有我收集以前学习心得，学习笔记，还有一线企业的工作经验，且给大定on零基础到项目实战的资料，大家也可以在下方，留言，把不懂的提出来，大家一起学习进步

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