143 lines
5.9 KiB
Python
143 lines
5.9 KiB
Python
"""
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分页组件，武沛奇视频课件讲解
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"""
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from django.utils.safestring import mark_safe
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class Pagination(object):
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def __init__(self, request, queryset, PAGE_SIZE=10, page_param='indexPage', PLUS_NAV=5):
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"""
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:param request: 视图函数,请求的对象
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:param queryset: 传递过来的查询结果集,符合条件的记录
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:param PAGE_SIZE: 每页显示记录数
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:param page_param: 前端传递过来的页码 eg:/list/?indexPage=12
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:param PLUS_NAV: 页码前后各几页
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"""
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# 为解决搜索后，分页导航url地址丢失的问题
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import copy
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# 将url地址中所带的参数复制一份
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query_dict = copy.deepcopy(request.GET)
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# 允许修改
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query_dict._mutable = True
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self.query_dict = query_dict
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self.page_param = page_param
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page = request.GET.get(page_param, '1') # 当前页,默认第1页,如果是跳转的就读indexPage输入框内的值
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if page.isdecimal(): # 判断page是否是一个数字
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page = int(page)
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else:
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page = 1
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self.page = page
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self.page_size = PAGE_SIZE # 每页10条数据
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self.star_page_data = (page - 1) * PAGE_SIZE # 开始数据
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self.end_page_data = page * PAGE_SIZE # 结束数据
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# star_page_data 开始记录数
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# end_page_data 结束记录数
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# [0:10] 取前10条数据
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self.page_queryset = queryset[self.star_page_data:self.end_page_data]
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# 统计共有多少条数据
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# total_count_data 总记录数
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total_count_data = queryset.count()
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# 计算总页数 方法：通过总记录数和每页显示数相除
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# divmod函数是python自带函数，计算两数相除同时获得商和余数，例如 divmod(91,10) 结果等于 {9,1}
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# total_count_page总页数 ， mod就是余数
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total_count_page, mod = divmod(total_count_data, PAGE_SIZE)
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if mod:
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total_count_page += 1 # 如果有余数总页数+1
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self.total_count_page = total_count_page
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self.plus_nav = PLUS_NAV
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# 生成分页导航条
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def html(self):
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"""
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生成分页导航条
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计算出当前页前5页和后5页的页码
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self.plus_nav 前后显示几页
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star_page 起始页
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end_page 结束页
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total_count_page 总页数
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page_nav 导航条的html代码
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"""
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# 计算导航栏页码数和显示方式（要考虑翻页时的极值）
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# 效果是前5页和后5页 self.plus_nav
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# 当数据量少比如只有100条数据以内，则展示全部导航条
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if self.total_count_page <= self.plus_nav * 2:
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star_page = 1
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end_page = self.total_count_page
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else: # 大于100条数据时 显示前后5条数据
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# 如果当前页小于5条（极植）
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if self.page <= self.plus_nav:
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star_page = 1
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end_page = self.plus_nav * 2
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else:
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# 当前是每后一页时（极植）
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if (self.page + self.plus_nav) >= self.total_count_page:
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star_page = self.total_count_page - self.plus_nav * 2 # 显示前10页导航
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end_page = self.total_count_page
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else:
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star_page = self.page - self.plus_nav
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end_page = self.page + self.plus_nav
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# 生成分页导航条的html代码，并传递给前端
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page_list = []
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# 首页
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# prev = '<li><a href="?page=1">首页</a></li>'
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# 向url地址中拼接参数
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self.query_dict.setlist(self.page_param, [1])
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# 取得拼接后的url地址self.query_dict.urlencode()
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prev = f'<li><a href="?{self.query_dict.urlencode()}" aria-label="Previous"><span aria-hidden="true">«</span></a></li>'
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page_list.append(prev)
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# 上一页
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if self.page > 1:
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self.query_dict.setlist(self.page_param, [self.page - 1])
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prev = f'<li><a href="?{self.query_dict.urlencode()}">上一页</a></li>'
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page_list.append(prev)
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for i in range(star_page, end_page + 1): # range前取后不取所以+1
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self.query_dict.setlist(self.page_param, [i])
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if i == self.page:
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ele = f'<li class="active"><a href="?{self.query_dict.urlencode()}">{i}</a></li>' # 给当前页加效果
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else:
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ele = f'<li><a href="?{self.query_dict.urlencode()}">{i}</a></li>'
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page_list.append(ele)
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# 下一页
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if self.page < self.total_count_page:
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self.query_dict.setlist(self.page_param, [self.page + 1])
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prev = f'<li><a href="?{self.query_dict.urlencode()}">下一页</a></li>'
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page_list.append(prev)
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# 尾页
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# prev = f'<li><a href="?page={total_count_page}">尾页</a></li>'
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self.query_dict.setlist(self.page_param, [self.total_count_page])
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prev = f'<li><a href="?{self.query_dict.urlencode()}" aria-label="Previous"><span aria-hidden="true">»</span></a></li>'
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page_list.append(prev)
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# 构建跳转html
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page_nav_search = """
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<li>
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<form method="get" style="float: left;margin-left: -1px">
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<input style="width: 100px;position: relative;float: left;display: inline-block;border-radius: 0" type="text" name="indexPage" class="form-control" placeholder="页码..">
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<button style="border-radius: 0;" class="btn btn-default" type="submit">跳转</button>
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</form>
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</li>
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"""
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page_list.append(page_nav_search)
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page_nav = ''.join(page_list)
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# 因为page_nav是一个html字符串，所以在传递到前端时要转换为安全的字符串
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page_nav = mark_safe(page_nav)
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"""分页实现结束"""
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return page_nav
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