Django自定义分页器

Posted 2020-11-21 zj420255586

自定义分页器基本思路

1. 获取用户想要访问的页码数

2. 每页展示条数

3. 每页的起始位置和终止位置

4. 统计数据库中数据的总条数

5. 计算展示所有数据需要多少页

6. 定义页码显示数量及规则

7. 查询用户想要查看的页码内容并返回

后端代码基本思路如下

def page_content(request):
    # 1. 获取用户想要访问的页码数
    current_page = int(request.POST.get('page'))        # 'page'为前端定义的页码
    
    # 2. 每页展示条数
    per_page_num = 10       # 每页展示10条数据
    
    # 3. 每页的起始位置和终止位置
    page_start = (current_page - 1) * per_page_num
    page_end = current_page * per_page_num
    
    # 4. 统计数据库中数据的总条数
    book_queryset = models.Book.objects.all()
    all_count = book_queryset.count()
    
    # 5. 计算展示所有数据需要多少页
    page_num, more = divmod(all_count, per_page_num)
    if more:
        page_num += 1
    
    # 6. 定义页码显示数量及规则
    page_html = ''
    middle_page = current_page       
    if middle_page < 6:
        middle_page = 6
    for i in range(current_page - 5, current_page + 6):
        if middle_page == i:
            page_html += f'<li class="active"><a href="?page={i}">{i}</a></li>'
        else:
            page_html += f'<li><a href="?page={i}">{i}</a></li>'
            
    # 7. 查询用户想要查看的页码内容并返回
    book_queryset = book_queryset[page_start: page_end]
    return render(request, 'page_content.html', locals())

一个已经封装好的分页器代码

分页器代码

# app01/utils/mypage.py     自定义工具一般放在应用的utils文件夹下
class Pagination(object):
    def __init__(self, current_page, all_count, per_page_num=10, 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('''
                    <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">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>
                                       ''')
        return ''.join(page_html_list)

后端代码

# views.py
from app01.utils.mypage import Pagination


def check_book(request):
    # 获取要展示数据的信息-->数据，用户点击页码，所有条数
    book_queryset = models.Book.objects.all()
    current_page = request.POST.get('page', 1)      # 当前点击页码，没有携带默认为1
    all_count = book_queryset.count()
    
    # 1.实例化产生对象
    page_obj = Pagination(current_page=current_page, all_count=all_count)
    
    # 2.对数据进行切片操作
    page_queryset = book_queryset[page_obj.start: page_obj.end]
    return render(request, 'check_book.html', locals())

前端代码

{# check_book.html #}
{% for book_obj in page_queryset %}
<p>{{ book_obj.title }}</p>
{% endfor %}
{{ page_obj.apge_html|safe }}