分页器推导

上面批量数据操作会让所有数据全部展示到一张页面上,基于上面的数据展示进行分页处理。每页展示几条

view.py

from django.shortcuts import render, HttpResponse, redirect
from app01 import models


def index(request):
    data_queryset = models.Book.objects.all()

    current_page_num = request.GET.get('page')
    try:

        current_page_num = int(current_page_num)

    except Exception:
        current_page_num = 1

    if not current_page_num:
        current_page_num = 1
    # 每页展示几条数据
    per_page_num = 10
    # 起始位置
    start_num = (current_page_num - 1) * per_page_num
    # 终止位置
    stop_num = current_page_num * per_page_num

    book_queryset = data_queryset[start_num:stop_num]  # 顾头不顾尾
    """
    per_page_num = 10
    current_page_num            start_num           stop_num
            1                       0                   10
            2                       10                  20
            3                       20                  30
            
    per_page_num = 5
    current_page_num            start_num           stop_num
            1                       0                   5
            2                       5                   10
            3                       10                  15
            
    规律: 
        start_num = (current_page_num-1) * per_page_num
        end_num = current_page_num * per_page_num    
    """

    # 前端渲染的页面数量
    all_count = data_queryset.count()
    # 内置方法之 divmod()
    page_num, more = divmod(all_count, per_page_num)
    if more:
        page_num += 1
    html = ''
    high_light_pag = current_page_num
    if current_page_num < 6:
        current_page_num = 6
    for i in range(current_page_num - 5, current_page_num + 6):
        if high_light_pag == i:
            html += '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i)
        else:
            html += '<li><a href="?page=%s">%s</a></li>' % (i, i)

    return render(request, 'index.html', locals())

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div class="text-center">
    {% for book_obj in book_queryset %}
        <p>{{ book_obj.title }}</p>
    {% endfor %}
    <nav aria-label="Page navigation">
        <ul class="pagination">
            <li>
                <a href="#" aria-label="Previous">
                    <span aria-hidden="true">&laquo;</span>
                </a>
            </li>
            {{ html|safe }}
            <li>
                <a href="#" aria-label="Next">
                    <span aria-hidden="true">&raquo;</span>
                </a>
            </li>
        </ul>
    </nav>
</div>


</body>
</html>

分页器封装模块

创建一个utils目录,写好的封装摸块的放在这个位置方便引用

my_page.py

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
        """
        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)

view.py

from django.shortcuts import render
from app01 import models


def index(request):
    from utils import my_page
    book_queryset = models.Book.objects.all()
    all_count = book_queryset.count()
    # 产生分页器对象
    page_obj = my_page.Pagination(current_page=request.GET.get('page'), all_count=all_count)
    # 产生分页数据对象
    page_queryset = book_queryset[page_obj.start:page_obj.end]
    return render(request, 'index.html', locals())

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div class="text-center">
    {% for book_obj in page_queryset %}
        <p>{{ book_obj.title }}</p>
    {% endfor %}
    {{ page_obj.page_html|safe}}
</div>
</body>
</html>
Last modification:May 29, 2022
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