自定义分页器

好久没来写东西那！今天写个自定义分页器给大家参考下吧

首先我们在自己创建的Django项目的app下新建一个utils文件夹，用来放我们的分页器组件

简单说下分页器实现原理：

　　1.利用ORM查询语句的限制数据条数来确定每页显示的数据

　　2.设置我们每页显示的数据条数以及每页显示的页码数（例如本次默认页码数是11）

　　3.判断要显示的数据条数的页码数是否大于我们设置的页码总数

　　4.如果大于,则判断是否是页码总数的前段还是后段，是否要翻页处理；比如我们设置的页码总数是11个，那么就是用当前页-1/2得到半数，最后根据半数的值判断是否翻页

　　5.先利用函数的方式实现，随后利用class来完成封装

我们在utils文件下创建有个pager.py的文件

"""
自定义分页组件的使用方法：
    pager_obj = Pagination(request.GET.get('page',1),len(HOST_LIST),request.path_info,request.GET)
    host_list = HOST_LIST[pager_obj.start:pager_obj.end]
    html = pager_obj.page_html()
    return render(request,'hosts.html',{'host_list':host_list,"page_html":html})
"""


class Pagination(object):
    """
    自定义分页
    """
    def __init__(self,current_page,total_count,base_url,params,per_page_count=10,max_pager_count=11):
        try:
            current_page = int(current_page)
        except Exception as e:
            current_page = 1
        if current_page <=0:
            current_page = 1
        self.current_page = current_page
        # 数据总条数
        self.total_count = total_count

        # 每页显示10条数据
        self.per_page_count = per_page_count

        # 页面上应该显示的最大页码
        max_page_num, div = divmod(total_count, per_page_count)
        if div:
            max_page_num += 1
        self.max_page_num = max_page_num

        # 页面上默认显示11个页面（当前页在中间）
        self.max_pager_count = max_pager_count
        self.half_max_pager_count = int((max_pager_count - 1) / 2)

        # URL前缀
        self.base_url = base_url

        # request.GET
        import copy
        params = copy.deepcopy(params)
        # 设置request能修改取到的值
        params._mutable = True
        # 包含当前列表页面所有的搜索条件
        # {source:[2,], status:[2], gender:[2],consultant:[1],page:[1]}
        # self.params[page] = 8
        # self.params.urlencode()
        # source=2&status=2&gender=2&consultant=1&page=8
        # href="/hosts/?source=2&status=2&gender=2&consultant=1&page=8"
        # href="%s?%s" %(self.base_url,self.params.urlencode())
        self.params = params

    @property
    def start(self):
        return (self.current_page - 1) * self.per_page_count

    @property
    def end(self):
        return self.current_page * self.per_page_count

    def page_html(self):
        # 如果总页数 <= 11
        if self.max_page_num <= self.max_pager_count:
            pager_start = 1
            pager_end = self.max_page_num
        # 如果总页数 > 11
        else:
            # 如果当前页 <= 5
            if self.current_page <= self.half_max_pager_count:
                pager_start = 1
                pager_end = self.max_pager_count
            else:
                # 当前页 + 5 > 总页码
                if (self.current_page + self.half_max_pager_count) > self.max_page_num:
                    pager_end = self.max_page_num
                    pager_start = self.max_page_num - self.max_pager_count + 1
                else:
                    pager_start = self.current_page - self.half_max_pager_count
                    pager_end = self.current_page + self.half_max_pager_count

        page_html_list = []
        # {source:[2,], status:[2], gender:[2],consultant:[1],page:[1]}
        self.params['page'] = 1
        first_page = '<a href="%s?%s">首页</a>' % (self.base_url,self.params.urlencode(),)
        page_html_list.append(first_page)
        # 上一页
        if self.current_page == 0:
            page_up = '<a href="%s?%s">上一页</a>' % (self.base_url,self.params.urlencode())
        else:
            self.params['page'] = self.current_page - 1
            page_up = '<a class="active" href="%s?%s">上一页</a>' % (self.base_url,self.params.urlencode())
        page_html_list.append(page_up)

        for i in range(pager_start, pager_end + 1):
            self.params['page'] = i
            if i == self.current_page:
                temp = '<a class="active" href="%s?%s">%s</a>' % (self.base_url,self.params.urlencode(), i,)
            else:
                temp = '<a href="%s?%s">%s</a>' % (self.base_url,self.params.urlencode(), i,)
            page_html_list.append(temp)

        # 下一页
        if self.current_page == self.max_page_num:
            page_down = '<a href="%s?%s">下一页</a>' % (self.base_url,self.params.urlencode())
        else:
            self.params['page'] = self.current_page + 1
            page_down = '<a class="active" href="%s?%s">下一页</a>' % (self.base_url,self.params.urlencode())
        page_html_list.append(page_down)

        self.params['page'] = self.max_page_num
        last_page = '<a href="%s?%s">尾页</a>' % (self.base_url, self.params.urlencode(),)
        page_html_list.append(last_page)

        return ''.join(page_html_list)

然后我们在view.py视图中调用

def hosts(request):
    from .utils.pager import Pagination
    HOST_LIST = []
    for i in range(1, 213):
        HOST_LIST.append("c%s.com" % i)
    pager_obj = Pagination(request.GET.get('page',1),len(HOST_LIST),request.path_info,request.GET)
    HOST_LIST = HOST_LIST[pager_obj.start:pager_obj.end]
    page_html = pager_obj.page_html()
    return render(request,'hosts.html',locals())

这样就完成那！