分頁功能的實現

weixin_34221276發表於2018-08-24

直接上程式碼吧:

基礎版

import math


class Page:

    def __init__(self, total_num, page_num, every_page_num=10, show_page_num=9):
        """
        :param total_num: 資料庫獲取到的資料的總數
        :param page_num: 前端獲取的頁數
        :param every_page_num: 自定義每頁顯示條數
        :param show_page_num: 顯示分頁數目
        """
        self.total_num = total_num
        self.page_num = page_num
        self.every_page_num = every_page_num
        self.show_page_num = show_page_num
        self.page_tags_html = ''
        self.page_start_num = 0
        self.page_end_num = 0
        self.start_page_num = 1
        self.end_page_num = 1
        try:
            self.page_num = int(self.page_num)
        except:
            self.page_num = 1
        # 通過向上取整計算出資料的總頁數
        self.total_page_num = math.ceil(self.total_num / self.every_page_num)
        if self.total_page_num:
            # 判斷從前端得到的頁碼數是否小於1，小於1就重置為1
            if self.page_num < 1:
                self.page_num = 1
            # 判斷從前端得到的頁碼數是否大於總頁碼數，大於就重置為最大頁碼數
            elif self.page_num > self.total_page_num:
                self.page_num = self.total_page_num
            # 當前頁的開始資料
            self.page_start_num = (self.page_num - 1) * self.every_page_num
            # 當前頁的結束資料
            self.page_end_num = (self.page_num) * self.every_page_num
            # 判斷總頁碼數和要展示的頁數，如果總頁碼數大於要展示的頁碼數就展示對應的頁數否則有多少頁就展示多少頁
            if self.total_page_num > self.show_page_num:
                self.start_page_num = self.page_num - (self.show_page_num // 2)
                self.end_page_num = self.page_num + (self.show_page_num // 2)
                if self.start_page_num < 1:
                    self.start_page_num = 1
                    self.end_page_num = self.show_page_num
                if self.end_page_num > self.total_page_num:
                    self.end_page_num = self.total_page_num
                    self.start_page_num = (self.total_page_num - self.show_page_num)
            else:
                self.start_page_num = 1
                self.end_page_num = self.total_page_num

    @property
    def start(self):
        return self.page_start_num

    @property
    def end(self):
        return self.page_end_num

    @property
    def html(self):
        pre_page_num = self.page_num - 1 if self.page_num > 1 else self.page_num
        next_page_num = self.page_num + 1 if self.page_num < self.total_page_num else self.total_page_num
        The_first_page = '<li><a href="?page=1">首頁</a>' \
                         f'</li><li><a href="?page={pre_page_num}">&laquo;</a></li>'
        The_last_page = f'<li><a href="?page={next_page_num}">&raquo;</a></li>' \
                        f'<li><a href="?page={self.total_page_num}">尾頁</a></li></ul></nav>'

        self.page_tags_html = f'<nav aria-label="Page navigation"> <ul class="pagination">{The_first_page}'
        for i in range(self.start_page_num, self.end_page_num + 1):
            if i == self.page_num:
                self.page_tags_html += f'<li class="active"><a href="?page={i}">{i}</a></li>'
            else:
                self.page_tags_html += f'<li><a href="?page={i}">{i}</a></li>'
        self.page_tags_html += The_last_page
        return self.page_tags_html

高階版（增加了url引數的保留功能）

import math
import copy

class Page:
    def __init__(self, total_num, page_num, request, every_page_num=10, show_page_num=9):
        """
        :param total_num: 資料庫獲取到的資料的總數
        :param request: 當前url請求資料，用於獲取url引數
        :param page_num: 前端獲取的頁數
        :param every_page_num: 自定義每頁顯示條數
        :param show_page_num: 顯示分頁數目
        """
        self.total_num = total_num
        self.page_num = page_num
        self.every_page_num = every_page_num
        self.show_page_num = show_page_num
        self.page_tags_html = ''
        self.page_start_num = 0
        self.page_end_num = 0
        self.start_page_num = 1
        self.end_page_num = 1

        try:
            self.page_num = int(self.page_num)
        except:
            self.page_num = 1

        # 獲取當前url請求中的引數
        params = copy.deepcopy(request.GET)
        self.params = params
        # 通過向上取整計算出資料的總頁數
        self.total_page_num = math.ceil(self.total_num / self.every_page_num)
        if self.total_page_num:
            # 判斷從前端得到的頁碼數是否小於1，小於1就重置為1
            if self.page_num < 1:
                self.page_num = 1
            # 判斷從前端得到的頁碼數是否大於總頁碼數，大於就重置為最大頁碼數
            elif self.page_num > self.total_page_num:
                self.page_num = self.total_page_num
            # 當前頁的開始資料
            self.page_start_num = (self.page_num - 1) * self.every_page_num
            # 當前頁的結束資料
            self.page_end_num = (self.page_num) * self.every_page_num
            # 判斷總頁碼數和要展示的頁數，如果總頁碼數大於要展示的頁碼數就展示對應的頁數否則有多少頁就展示多少頁
            if self.total_page_num > self.show_page_num:
                self.start_page_num = self.page_num - (self.show_page_num // 2)
                self.end_page_num = self.page_num + (self.show_page_num // 2)
                if self.start_page_num < 1:
                    self.start_page_num = 1
                    self.end_page_num = self.show_page_num
                if self.end_page_num > self.total_page_num:
                    self.end_page_num = self.total_page_num
                    self.start_page_num = (self.total_page_num - self.show_page_num)
            else:
                self.start_page_num = 1
                self.end_page_num = self.total_page_num

    @property
    def start(self):
        return self.page_start_num

    @property
    def end(self):
        return self.page_end_num

    @property
    def html(self):

        pre_page_num = self.page_num - 1 if self.page_num > 1 else self.page_num
        next_page_num = self.page_num + 1 if self.page_num < self.total_page_num else self.total_page_num
        self.params["page"] = 1
        The_home_page_html = f'<li><a href="?{self.params.urlencode()}">首頁</a></li>'
        self.params["page"] = pre_page_num
        pre_page_num_html = f'<li><a href="?{self.params.urlencode()}">&laquo;</a></li>'
        The_first_page_html = The_home_page_html + pre_page_num_html
        self.params["page"] = next_page_num
        next_page_num_html = f'<li><a href="?{self.params.urlencode()}">&raquo;</a></li>'
        self.params["page"] = self.total_page_num
        The_end_page_html = f'<li><a href="?{self.params.urlencode()}">尾頁</a></li></ul></nav>'
        The_last_page_html = next_page_num_html + The_end_page_html
        self.page_tags_html = f'<nav aria-label="Page navigation"> <ul class="pagination">{The_first_page_html}'
        for i in range(self.start_page_num, self.end_page_num + 1):
            self.params["page"] = i
            if i == self.page_num:
                self.page_tags_html += f'<li class="active"><a href="?{self.params.urlencode()}">{i}</a></li>'
            else:
                self.page_tags_html += f'<li><a href="?{self.params.urlencode()}">{i}</a></li>'
        self.page_tags_html += The_last_page_html

        return self.page_tags_html

分頁的使用：

class Home(views.View):
    def get(self, request):
        article_list = models.Article.objects.all()
        totol_num = article_list.count()
        page_num = request.GET.get("page", 1)
        # 分頁例項化傳參
        page_obj = Page(total_num=totol_num, page_num=page_num, every_page_num=9)
        # 根據分頁拿到的start和end切片得到所要的資料
        data = article_list[page_obj.start:page_obj.end]
        # 呼叫html方法得到分頁的html程式碼片段
        page_html = page_obj.html
        return render(request, 'home.html', {'article_list': data, 'page_html': page_html})

ps:在python指令碼中呼叫django環境實現資料庫批量新增資料操作

import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "fenye.settings")

if __name__ == "__main__":
    import django
    django.setup()
    from app01 import models


    def create():
        obj_list = [models.Book(name = f"pyhton{i}") for i in range(160)]
        models.Book.objects.bulk_create(obj_list)

    create()
    #
    # def delete():
    #     models.Book.objects.all().delete()

    # delete()

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