"""分页组件使用示例：    1) 先取出所有数据USER_LIST    2) 实例化：        obj = Pagination(request.GET.get('page',1), len(USER_LIST), request)    3) 对所有数据列表切片（即切出一页数据）：        page_user_list = USER_LIST[obj.start:obj.end]    4) 返回给页面：        return render(request,'index.html',{'users': page_user_list, 'obj': obj})    5) 模板页面通过 {
   { obj.page_html|safe }} 渲染页码"""

class Pagination(object):    # 第一步  初始化页面    def __init__(self,current_page_num,all_count,request,per_page_num=5,pager_count=11):        """        封装分页相关数据        :param current_page_num: 当前访问页的数字        :param all_count:    分页数据中的数据总条数        :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_num = int(current_page_num)        except Exception as e:            current_page_num = 1        if current_page_num <1:            current_page_num = 1        self.current_page_num = current_page_num        self.all_count = all_count        self.per_page_num = per_page_num        # 第二步  实际总页码        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)  # 5        # 保存搜索条件        import copy        self.params=copy.deepcopy(request.GET) # {"a":"1","b":"2"}    @property  #属性方法  在外部views里 切片的时候不用加括号  直接调用 start就可以    def start(self):        return (self.current_page_num - 1) * self.per_page_num    @property    def end(self):        return self.current_page_num * 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_num <= 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_num + self.pager_count_half) > self.all_pager:                    pager_start = self.all_pager - self.pager_count + 1                    pager_end = self.all_pager + 1                else:                    pager_start = self.current_page_num - self.pager_count_half                    pager_end = self.current_page_num + self.pager_count_half + 1        page_html_list = []        first_page = '
首页
' % (1,)        page_html_list.append(first_page)        if self.current_page_num <= 1:            prev_page = '
上一页
'        else:            prev_page = '
上一页
' % (self.current_page_num - 1,)        page_html_list.append(prev_page)        #self.params=copy.deepcopy(request.GET) # {"a":"1","b":"2"}        # 主要的for循环        for i in range(pager_start, pager_end):            self.params["page"]=i            if i == self.current_page_num:                temp = '
%s
' %(self.params.urlencode(),i)            else:                temp = '
%s
' % (self.params.urlencode(),i,)            page_html_list.append(temp)        if self.current_page_num >= self.all_pager:            next_page = '
下一页
'        else:            next_page = '
下一页
' % (self.current_page_num + 1,)        page_html_list.append(next_page)        last_page = '
尾页
' % (self.all_pager,)        page_html_list.append(last_page)        return ''.join(page_html_list)