9.18 关于分页的方法
2018-9-18 17:38:24
数据比较多少的时候需要分页!
所有就引出了分页 根据if 判断分页!逻辑很重要!但牵扯到的都是基础知识
先放上原始版的views 的功能代码
明天再看下午内容!
from django.shortcuts import render # Create your views here. from app01 import models def books(request): # 从URL取参数 page_num = request.GET.get("page") print(page_num, type(page_num)) # 总数据是多少 total_count = models.Book.objects.all().count() # # 每一页显示多少条数据 # per_page = 10 # # # 总共需要多少页码来展示 # total_page, m = divmod(total_count, per_page) # if m: # total_page += 1 # try: # page_num = int(page_num) # # 如果输入的页码数超过了最大的页码数，默认返回最后一页 # if page_num > total_page: # page_num = total_page # except Exception as e: # # 当输入的页码不是正经数字的时候 默认返回第一页的数据 # page_num = 1 # # # 定义两个变量保存数据从哪儿取到哪儿 # data_start = (page_num-1)*10 # data_end = page_num*10 # # # 页面上总共展示多少页码 # max_page = 11 # if total_page < max_page: # max_page = total_page # # half_max_page = max_page // 2 # # 页面上展示的页码从哪儿开始 # page_start = page_num - half_max_page # # 页面上展示的页码到哪儿结束 # page_end = page_num + half_max_page # # 如果当前页减一半 比1还小 # if page_start <= 1: # page_start = 1 # page_end = max_page # # 如果 当前页 加 一半 比总页码数还大 # if page_end >= total_page: # page_end = total_page # page_start = total_page - max_page +1 # # all_book = models.Book.objects.all()[data_start:data_end] # # # 自己拼接分页的HTML代码 # html_str_list = [] # # 加上第一页 # html_str_list.append('<li><a href="/books/?page=1">首页</a></li>') # # # 判断一下 如果是第一页，就没有上一页 # if page_num <= 1: # html_str_list.append('<li class="disabled"><a href="#"><span aria-hidden="true">«</span></a></li>'.format(page_num-1)) # else: # # 加一个上一页的标签 # html_str_list.append('<li><a href="/books/?page={}"><span aria-hidden="true">«</span></a></li>'.format(page_num-1)) # # for i in range(page_start, page_end+1): # # 如果是当前页就加一个active样式类 # if i == page_num: # tmp = '<li class="active"><a href="/books/?page={0}">{0}</a></li>'.format(i) # else: # tmp = '<li><a href="/books/?page={0}">{0}</a></li>'.format(i) # # html_str_list.append(tmp) # # # 加一个下一页的按钮 # # 判断，如果是最后一页，就没有下一页 # if page_num >= total_page: # html_str_list.append('<li class="disabled"><a href="#"><span aria-hidden="true">»</span></a></li>') # else: # html_str_list.append('<li><a href="/books/?page={}"><span aria-hidden="true">»</span></a></li>'.format(page_num+1)) # # 加最后一页 # html_str_list.append('<li><a href="/books/?page={}">尾页</a></li>'.format(total_page)) # # page_html = "".join(html_str_list) # # 调用一个类 from utils.mypage import Page page_obj = Page(page_num, total_count, per_page=10, url_prefix="/books/", max_page=9,) ret = models.Book.objects.all()[page_obj.start:page_obj.end] page_html = page_obj.page_html() return render(request, "books.html", {"books": ret, "page_html": page_html}) def depts(request): # 从URL取参数 page_num = request.GET.get("page") print(page_num, type(page_num)) # 总数据是多少 total_count = models.Dept.objects.all().count() from utils.mypage import Page page_obj = Page(page_num, total_count, per_page=10, url_prefix="/depts/", max_page=11, ) ret = models.Dept.objects.all()[page_obj.start:page_obj.end] print(ret) page_html = page_obj.page_html() return render(request, "dept.html", {"depts": ret, "page_html": page_html})
再放上 直接 封装一个类 实现功能!! 面向对象 封装!
class Page(): def __init__(self, page_num, total_count, url_prefix, per_page=10, max_page=11): """ :param page_num: 当前页码数 :param total_count: 数据总数 :param url_prefix: a标签href的前缀 :param per_page: 每页显示多少条数据 :param max_page: 页面上最多显示几个页码 """ self.url_prefix = url_prefix self.max_page = max_page # 每一页显示多少条数据 # 总共需要多少页码来展示 total_page, m = divmod(total_count, per_page) if m: total_page += 1 self.total_page = total_page try: page_num = int(page_num) # 如果输入的页码数超过了最大的页码数，默认返回最后一页 if page_num > total_page: page_num = total_page except Exception as e: # 当输入的页码不是正经数字的时候 默认返回第一页的数据 page_num = 1 self.page_num = page_num # 定义两个变量保存数据从哪儿取到哪儿 self.data_start = (page_num - 1) * 10 self.data_end = page_num * 10 # 页面上总共展示多少页码 if total_page < self.max_page: self.max_page = total_page half_max_page = self.max_page // 2 # 页面上展示的页码从哪儿开始 page_start = page_num - half_max_page # 页面上展示的页码到哪儿结束 page_end = page_num + half_max_page # 如果当前页减一半 比1还小 if page_start <= 1: page_start = 1 page_end = self.max_page # 如果 当前页 加 一半 比总页码数还大 if page_end >= total_page: page_end = total_page page_start = total_page - self.max_page + 1 self.page_start = page_start self.page_end = page_end @property def start(self): return self.data_start @property def end(self): return self.data_end def page_html(self): # 自己拼接分页的HTML代码 html_str_list = [] # 加上第一页 html_str_list.append('<li><a href="{}?page=1">首页</a></li>'.format( self.url_prefix)) # 判断一下 如果是第一页，就没有上一页 if self.page_num <= 1: html_str_list.append('<li class="disabled"><a href="#"><span aria-hidden="true">«</span></a></li>'.format(self.page_num-1)) else: # 加一个上一页的标签 html_str_list.append('<li><a href="{}?page={}"><span aria-hidden="true">«</span></a></li>'.format( self.url_prefix, self.page_num-1)) for i in range(self.page_start, self.page_end+1): # 如果是当前页就加一个active样式类 if i == self.page_num: tmp = '<li class="active"><a href="{0}?page={1}">{1}</a></li>'.format(self.url_prefix, i) else: tmp = '<li><a href="{0}?page={1}">{1}</a></li>'.format( self.url_prefix, i) html_str_list.append(tmp) # 加一个下一页的按钮 # 判断，如果是最后一页，就没有下一页 if self.page_num >= self.total_page: html_str_list.append('<li class="disabled"><a href="#"><span aria-hidden="true">»</span></a></li>') else: html_str_list.append('<li><a href="{}?page={}"><span aria-hidden="true">»</span></a></li>'.format( self.url_prefix, self.page_num+1)) # 加最后一页 html_str_list.append('<li><a href="{}?page={}">尾页</a></li>'.format( self.url_prefix, self.total_page)) page_html = "".join(html_str_list) return page_html
