分页

class Pagination(object):
    def __init__(self, current_page, all_count, per_page_num=8, pager_count=11):
        """
        封装分页相关数据
        :param current_page: 当前页
        :param all_count:    数据库中的数据总条数
        :param per_page_num: 每页显示的数据条数
        :param pager_count:  最多显示的页码个数

        ```
            用法:
            queryset = model.objects.all()
            page_obj = Pagination(current_page,all_count)
            page_data = queryset[page_obj.start:page_obj.end]
            获取数据用page_data而不再使用原始的queryset
            获取前端分页样式用page_obj.page_html
            """

        try:
            current_page = int(current_page)
        except Exception as e:
            current_page = 1

        if current_page < 1:
            current_page = 1

        self.current_page = current_page

        self.all_count = all_count
        self.per_page_num = per_page_num

        # 总页码
        all_pager, tmp = divmod(all_count, per_page_num)
        if tmp:
            all_pager += 1
        self.all_pager = all_pager

        self.pager_count = pager_count
        self.pager_count_half = int((pager_count - 1) / 2)


    @property
    def start(self):
        return (self.current_page - 1) * self.per_page_num


    @property
    def end(self):
        return self.current_page * self.per_page_num


    def page_html(self):
        # 如果总页码 < 11个：
        if self.all_pager <= self.pager_count:
            pager_start = 1
            pager_end = self.all_pager + 1
        # 总页码  > 11
        else:
            # 当前页如果<=页面上最多显示11/2个页码
            if self.current_page <= self.pager_count_half:
                pager_start = 1
                pager_end = self.pager_count + 1

            # 当前页大于5
            else:
                # 页码翻到最后
                if (self.current_page + self.pager_count_half) > self.all_pager:
                    pager_end = self.all_pager + 1
                    pager_start = self.all_pager - self.pager_count + 1
                else:
                    pager_start = self.current_page - self.pager_count_half
                    pager_end = self.current_page + self.pager_count_half + 1

        page_html_list = []
        # 添加前面的nav和ul标签
        page_html_list.append('''
                    <div class='text-center'>
                    <nav aria-label='Page navigation>'
                    <ul class='pagination'>
                  
                ''')
        first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
        page_html_list.append(first_page)

        if self.current_page <= 1:
            prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
        else:
            prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)

        page_html_list.append(prev_page)

        for i in range(pager_start, pager_end):
            if i == self.current_page:
                temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
            else:
                temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
            page_html_list.append(temp)

        if self.current_page >= self.all_pager:
            next_page = '<li class="disabled"><a href="#">下一页</a></li>'
        else:
            next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
        page_html_list.append(next_page)

        last_page = '<li><a href="?page=%s" id="weiye">尾页</a></li>' % (self.all_pager,)
        page_html_list.append(last_page)
        # 尾部添加标签
        page_html_list.append('''
                                           </nav>
                                           </ul>
                                           </div>
                                       ''')
        return ''.join(page_html_list)

自定义分页

django内置分页

# 内置分页需要导入django中的类
    from django.core.paginator import Paginator
    paginator = Paginator(user_list,10)
    # 第一个参数是我们查出来的所有的对象， 第二个参数表示的是每页显示的行数
    # 生成一个paginator对象 paginator可以点出如下的方法
    # per_page: 每页显示条目的数量(多少行)
    # count:    总数据的个数
    # num_pages: 总页数
    # page_range: 总页数的索引范围，eg: (1,10) 表示第1页到第10页
    # page：      page对象

    users = paginator.page(cur_page)    # 需要把当前页数传进去
    # 生成page对象，page对象有如下的方法
    # has_next              是否有下一页
    # next_page_number      下一页的页码
    # has_previous          是否有上一页
    # previous_page_number  上一页的页码
    # object_list           分页之后的数据列表QuerySet  列表中套对象
    # number                当前页
    # paginator             paginator对象

后端逻辑

def classes(request):
    if request.method == 'GET':

        current_page = request.GET.get('page', 1)
        classes_list = models.Classes.objects.all()
        all_count = classes_list.count()
        page_obj = mypage.Pagination(current_page=current_page, all_count=all_count)
        page_queryset = classes_list[page_obj.start:page_obj.end]
        return render(request, 'classes.html', locals())
    else:
        redirect('/appclasses/classes/')