二十一、分页

原理

def index(request):
    per_page_count = 10
    current_page=request.GET.get('p')
    # page=1 0,10 0-9
    # page=2 10,20 10-19
    current_page = int(current_page)
    start = (current_page - 1) * per_page_count
    end = current_page * per_page_count
    data=USER_LIST[start:end]
    return render(request,'index.html',{'user_list':data})

1、Django内置分页

def index1(request):
    from django.core.paginator import Paginator,EmptyPage,PageNotAnInteger
     # 全部数据:USER_LIST,=> 得出共有多少条数据
     # per_page: 每页显示条目数量
     # count: 数据总个数
     # num_pages: 总页数
     # page_range: 总页数的索引范围:如:(1,10),(1,200)
     # page: page对象(是否有下一页;是否有上一页)
    paginator = Paginator(USER_LIST, 10)
    current_page = request.GET.get("p")
    try:
         # page对象
         posts = paginator.page(current_page)
         #     han_next 是否有下一页
         #     next_page_number 下一页页码
         #     has_previous 是否有上一页
         #     previous_page_number 上一页页码
         #     object_list 分页之后的数据列表,已经切片好的数据
         #     number 当前页
         #     paginator paginator对象
     except PageNotAnInteger:
         posts = paginator.page(1)
     except EmptyPage:
         posts = paginator.page(paginator.num_pages)

     return render(request,'index1.html',{'posts':posts})
<body>
  <ul>
    {% for row in posts.object_list %}
    <li>{{ row.name }}-{{ row.age }}</li>
    {% endfor %}
  </ul>
  {% include 'include/pager.html' %}
</body>

将分页代码独立:在template下新建目录include,在include创建pager.html

{% if posts.has_previous %}
    <a href="/index1.html?p={{ posts.previous_page_number }}">上一页</a>
{% endif %}
{% if posts.has_next %}
    <a href="/index1.html?p={{ posts.next_page_number }}">下一页</a>
{% endif %}
<span>
    {{ posts.number }} / {{ posts.paginator.num_pages }}
</span>

2、扩展django的内置分页

class MyPaginator(Paginator):
    def __init__(self,current_page,per_pager_num,*args,**kwargs):
        # 当前页
        self.current_page = int(current_page)
        # 最多显示的页码数量
        self.per_pager_num = int(per_pager_num)
        super(MyPaginator,self).__init__(*args,**kwargs)

    # 在页面中显示页码的范围
    def pager_num_range(self):
        if self.num_pages < self.per_pager_num:
            return range(1,self.num_pages+1)
        #  总页数特别多
        part = int(self.per_pager_num/2)
        if self.current_page <= part:
            return range(1,self.per_pager_num+1)
        if self.current_page >= self.num_pages - part:
            return range(self.num_pages - self.per_pager_num + 1,self.num_pages+1)
        return range(self.current_page - part, self.current_page + part + 1)
{% if posts.has_previous %}
    <a href="/index1.html?p={{ posts.previous_page_number }}">上一页</a>
{% endif %}
// 显示页码数字,提供跳转
{% for i in posts.paginator.pager_num_range %}
    {% if i == posts.number %}
        <a href="/index1.html?p={{ i }}" style="font-size: 30px;">{{ i }}</a>
    {% else %}
        <a href="/index1.html?p={{ i }}">{{ i }}</a>
    {% endif %}
{% endfor %}
{% if posts.has_next %}
    <a href="/index1.html?p={{ posts.next_page_number }}">下一页</a>
{% endif %}
<span>
    {{ posts.number }} / {{ posts.paginator.num_pages }}
</span>

3、自定义分页

传入:所有数据的个数、当前页、每页显示条数、最多页码个数

class Pagination(object):
   def __init__(self,totalCount,currentPage,perPageItemNum=10,maxPageNum=7):
       # 数据总个数
       self.total_count = totalCount
       # 当前页
       try:
          v = int(currentPage)
          if v<=0:
             v=1
          self.current_page = v
       except Exception as e:
          self.current_page = 1
       # 每页显示的行数
       self.per_page_item_num = perPageItemNum
       # 最多显示页码
       self.max_page_num = maxPageNum


    def start(self):
       return (self.current_page-1)*self.per_page_item_num

    def end(self):
       return self.current_page*self.per_page_item_num

    # @property 将方法伪装成属性
    @property
    def num_pages(self):
       """
       总页数
       """
       """divmod python函数 传入被除数和除数 返回 商和余数"""
       a,b = divmod(self.total_count,self.per_page_item_num)
       if b == 0:
          return a
       return a+1

    def pager_num_range(self):
       if self.num_pages < self.max_page_num:
          return range(1,self.num_pages+1)
       #  总页数特别多
       part = int(self.max_page_num/2)
       if self.current_page <= part:
          return range(1,self.max_page_num+1)
       if self.current_page >= self.num_pages - part:
          return range(self.num_pages - self.max_page_num + 1,self.num_pages+1)
       return range(self.current_page - part, self.current_page + part + 1)


    def page_str(self):
       page_list=[]

       first="<li><a href='/index2.html?p=1'>首页</a></li>"
       page_list.append(first)

       if self.current_page==1:
          prev="<li><a href='#'>上一页</a></li>"
       else:
          prev = "<li><a href='/index2.html?p=%s'>上一页</a></li>"%(self.current_page-1)
       page_list.append(prev)

       for i in self.pager_num_range():
          if i==self.current_page:
             temp = "<li class='active'><a href='/index2.html?p=%s'>%s</a></li>" % (i, i)
          else:
             temp = "<li><a href='/index2.html?p=%s'>%s</a></li>"%(i,i)
          page_list.append(temp)

       if self.current_page==self.num_pages:
          nex = "<li><a href='#'>下一页</a></li>"
       else:
         nex = "<li><a href='/index2.html?p=%s'>下一页</a>"%(self.current_page+1)
       page_list.append(nex)

       last="<li><a href='/index2.html?p=%s'>尾页</a></li>"%(self.num_pages)
       page_list.append(last)

       return ''.join(page_list)
<body>
  <ul>
    {% for row in data %}
    <li>{{ row.name }}-{{ row.age }}</li>
    {% endfor %}
  </ul>

  <ul class="pagination pagination-sm">
    {{ page_obj.page_str|safe }}
  </ul>
</body>
posted @   Bruce_JRZ  阅读(4)  评论(0编辑  收藏  举报
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