18-1 分頁功能

一 本身封裝一個分頁類mypage

"""
網頁分頁功能，封裝了一個類，若是要使用須要傳三個參數，current_page, total_count, url_prefix
"""


# 封裝分頁類
class MyPage(object):

    def __init__(self, current_page, total_count, url_prefix, per_page=10, max_show=7):
        """
        初始化一個我本身定義的分頁實例
        :param current_page: 當前頁碼
        :param total_count: 總的數據量
        :param url_prefix: 分頁中a標籤的url前綴
        :param per_page: 每個顯示多少條數據
        :param max_show: 頁面上最多顯示多少個頁碼
        """
        self.total_count = total_count
        self.per_page = per_page
        self.max_show = max_show
        self.url_prefix = url_prefix

        # 最多顯示頁碼數的一半
        half_show = max_show // 2
        #    由於URL取到的參數是字符串格式，須要轉換成int類型
        try:
            current_page = int(current_page)
        except Exception as e:
            # 若是輸入的頁碼不是正經頁碼，默認展現第一頁
            current_page = 1
        # 求總共須要多少頁顯示
        total_page, more = divmod(total_count, per_page)
        if more:
            total_page += 1
        # 若是輸入的當前頁碼數大於總數據的頁碼數，默認顯示最後一頁
        if current_page > total_page:
            current_page = total_page
        self.current_page = current_page

        # 計算一下顯示頁碼的起點和終點
        show_page_start = current_page - half_show
        show_page_end = current_page + half_show
        # 特殊狀況特殊處理
        # 1. 當前頁碼 - half_show <= 0
        if current_page - half_show <= 0:
            show_page_start = 1
            show_page_end = max_show
        # 2. 當前頁碼數 + hale_show >= total_page
        if current_page + half_show >= total_page:
            show_page_end = total_page
            show_page_start = total_page - max_show + 1
        # 3. 總共須要的頁碼數 < max_show
        if total_page < max_show:
            show_page_start = 1
            show_page_end = total_page

        self.show_page_start = show_page_start
        self.show_page_end = show_page_end
        self.total_page = total_page

    # 數據切片的起點
    @property
    def start(self):
        return (self.current_page - 1) * self.per_page

    # 數據切片的終點
    @property
    def end(self):
        return self.current_page * self.per_page
    # 序號也跟着變
    def num(self):
        return (self.current_page-1)*self.per_page

    # 分頁的html代碼
    def page_html(self):
        tmp = []
        page_html_start = '<nav aria-label="Page navigation" class="text-center"><ul class="pagination">'
        page_html_end = '</ul></nav>'
        tmp.append(page_html_start)
        # 添加一個首頁
        tmp.append('<li><a href="/{}?page=1">首頁</a></li>'.format(self.url_prefix))
        # 添加一個上一頁
        # 噹噹前頁是第一頁的時候不能再點擊上一頁
        if self.current_page - 1 <= 0:
            tmp.append(
                '<li class="disabled"><a href="#" aria-label="Previous"><span aria-hidden="true">&laquo;</span></a></li>')
        else:
            tmp.append(
                '<li><a href="/{}?page={}" aria-label="Previous"><span aria-hidden="true">&laquo;</span></a></li>'.format(
                    self.url_prefix, self.current_page - 1))
        # for循環添加要展現的頁碼
        for i in range(self.show_page_start, self.show_page_end + 1):
            # 若是for循環的頁碼等於當前頁碼，給li標籤加一個active的樣式
            if self.current_page == i:
                tmp.append('<li class="active"><a href="/{1}?page={0}">{0}</a></li>'.format(i, self.url_prefix))
            else:
                tmp.append('<li><a href="/{1}?page={0}">{0}</a></li>'.format(i, self.url_prefix))
        # 添加一個下一頁
        # 當前 當前頁已是最後一頁，應該不讓下一頁按鈕能點擊
        if self.current_page + 1 > self.total_page:
            tmp.append(
                '<li class="disabled"><a href="#" aria-label="Previous"><span aria-hidden="true">&raquo;</span></a></li>')
        else:
            tmp.append(
                '<li><a href="/{}?page={}" aria-label="Previous"><span aria-hidden="true">&raquo;</span></a></li>'.format(
                    self.url_prefix, self.current_page + 1))
        # 添加一個尾頁
        tmp.append('<li><a href="/{}?page={}">尾頁</a></li>'.format(self.url_prefix, self.total_page))
        tmp.append(page_html_end)

        page_html = "".join(tmp)
        return page_html

View Code

二  而後在views函數裏面調用

記得先導入你本身寫的那個類

import mypage

def book_list(request):
    book = models.Book.objects.all()
    total_count = book.count()
    current_page = request.GET.get("page")
    # 分頁功能開始
    page_boj = mypage.MyPage(current_page, total_count, url_prefix="book_list")
    data = book[page_boj.start:page_boj.end]  # 從第幾頁顯示到第幾頁
    page_html = page_boj.page_html()  # 頁面
    page_num = page_boj.num()  # 序號
    return render(request, "book_list.html", {"book": data, "page_html": page_html, "num": page_num})

三  html設置

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>列表</title>
    <link rel="stylesheet" href="/static/bootstrap-3.3.7/css/bootstrap.min.css">
</head>
<body>
<div class="container">
    <div class="row">
        <div class="col-md-8 col-md-offset-2">
{#             # table-striped 設置灰色背景#}
            <table class="table table-bordered table-striped">
                <thead>
                <tr>
                    <th>序號</th>
                    <th>id</th>
                    <th>書名</th>
                    <th>出版社id</th>
                </tr>
                </thead>
                <tbody>
                {% for book in book %}
                    <tr>
                        <td>{{ forloop.counter|add:num}}</td>
                        <td>{{ book.id }}</td>
                        <td>{{ book.title }}</td>
                        <td>{{ book.publisher.name }}</td>
                    </tr>
                {% endfor %}
                </tbody>

            </table>
        {{ page_html|safe }}

        </div>


    </div>

</div>

</body>
</html>

View Code

四 驗證：

如何快速向數據庫中插入批量數據，建立的時候用bulk_creat去建立

 1 import os
 2 import django
 3 if __name__ == "__main__":
 4     os.environ.setdefault("DJANGO_SETTINGS_MODULE", "練習.settings")
 5     django.setup()
 6     from app01 import models
 7     # 建立500個書籍對象
 8     book_list=[models.Book(title="貝多芬第{}交響曲".format(i),publisher_id=i) for i in range (500)]
 9     # 批量提交到數據庫
10     models.Book.objects.bulk_create(book_list)