python2.0_day19_前端分页功能的实现

$python3.5 manage.py  shell
>>> from django.core.paginator import Paginator # 导入Paginator
>>> objects = [‘john‘,‘paul‘,‘george‘,‘ringo‘]
>>> p = Paginator(objects,2)    # 生成一个分页的实例,两个参数(objects是列表,2代表的是每2个元素分成一页.)

>>> p.count             # 查看有多少个元素
4
>>> p.num_pages         # 查看总共有几页
2
>>> type(p.page_range)
<class‘range‘>
>>> p.page_range        # 当我们想循环每一页时就需要用到这个. for num in p.page_range:page = p.page(1)
range(1, 3)
>>> page1 = p.page(1)   # p.page(num) 取第几页
>>> page1               # page1 显示这事第几页
<Page 1 of 2>
>>> page1.object_list   # 显示页里面的元素,以列表的方式
[‘john‘, ‘paul‘]
>>> p.object_list       # 显示p实例里有多少个元素
[‘john‘, ‘paul‘, ‘george‘, ‘ringo‘]

>>> page2 = p.page(2)   # 第二页
>>> page2.object_list   # 查看第二页有多少个元素
[‘george‘, ‘ringo‘]
>>> page2.has_next()    # 查看当前页是不是有下一页,如果有返回True,如果没有Flase
False
>>> page2.has_previous()    # 查看当前页是不是有上一页,如果有返回True,如果没有返回False
True
>>> page2.has_other_pages() # 查看除了当前页之外还有没有其它页,如果有返回True,如果没有返回False
True
>>> page1.next_page_number() # 查看当前页的下一页的页码
2
>>> page2.next_page_number()    # 查看当前页的下一页的页码,如果没有则报错
Traceback (most recent call last):
......
django.core.paginator.EmptyPage: That page contains no results
>>> page2.previous_page_number()    # 查看当前页的上一页的页码.
1
>>> page1.previous_page_number()    # 查看当前页的上一页的页码,如果没有则报错
Traceback (most recent call last):
......
django.core.paginator.EmptyPage: That page number is less than 1

>>> page1.start_index() # 查看当前页中,第一个元素在总列表的索引值
1
>>> page2.start_index() # 查看当前页中,第一个元素在总列表的索引值
3
>>> page1.end_index()   # 查看当前页中,最后一个元素在总列表的索引值
2
>>> page2.end_index()   # 查看当前页中,最后一个元素在总列表的索引值
4
>>> p.page(0)   # 当所取页超出p.page_range()范围,就会报错了
Traceback (most recent call last):
...
django.core.paginator.EmptyPage: That page number is less than 1

             1
            from
             django.shortcuts import render

             2
            from
             crm import models

             3
            from
             django.core.paginator import  import Paginator,EmptyPage,PageNotAnInteger # 两个异常

             4
            # Create your views here.

             5
             6
            def dashboard(request):

             7
            return render(request,‘crm/dashboard.html‘)
 8def customers(request):
 9     customer_list = models.Customer.objects.all()
10     paginator = Paginator(customer_list,2) # 每页显示2条纪录
11     page = request.GET.get(‘page‘) #获取客户端请求传来的页码
12try:
13         customer_list = paginator.page(page) # 返回用户请求的页码对象
14    except PageNotAnInteger:   # 如果请求中的page不是数字,也就是为空的情况下
15         customer_list = paginator.page(1)
16    except EmptyPage:
17        # 如果请求的页码数超出paginator.page_range(),则返回paginator页码对象的最后一页
18         customer_list = paginator.page(paginator.num_pages)
1920return render(request,‘crm/customers.html‘,{‘customer_list‘:customer_list})

<li class="active"><a href="?page={{page_num}}">{{page_num}}<span class="sr-only">(current)</span></a></li>

             1     <div class="pagination">
 2 3         <nav>
 4             <ul class="pagination">
 5                 {% if customer_list.has_previous %}
 6                     <li class=""><a href="?page={{customer_list.previous_page_number}}" aria-label="Previous"><span aria-hidden="true">&laquo;</span></a></li>
 7                 {% endif %}
 8                 <!--<li class="active"><a href="#">1 <span class="sr-only">(current)</span></a></li>-->
 9                 <!--我们要想获得所有的页面是不是先要知道有多少页,然后对页码进行循环
10                 这里需要注意:我们知道paginator有一个方法page_range,可以获得range(1,总页数+1)这个<class‘range‘>,但是我们这里的customer_list只是一个页码实例,它怎么获得range类型呢
11                 可以,可以使用customer_list.paginator.page_range这样就获得了range(1,总页数+1)这个<class‘range‘>,接下来就是对这个range进行循环就可以了.
12                 -->
13                 {% for page_num in customer_list.paginator.page_range %}
14                     {% if page_num  == customer_list.number %}
15                         <li class="active"><a href="?page={{page_num}}">{{page_num}}<span class="sr-only">(current)</span></a></li>
16                     {% else %}
17                         <li class=""><a href="?page={{page_num}}">{{page_num}}<span class="sr-only">(current)</span></a></li>
18                     {% endif %}
19                 {% endfor %}
2021                 {% if customer_list.has_next %}
22                     <li class=""><a href="?page={{customer_list.next_page_number}}" aria-label="Next"><span aria-hidden="true">&raquo;</span></a></li>
23                 {% endif %}
2425             </ul>
26         </nav>
27     </div>

            1
            from
             django import template

            2
            3     register = template.Library() # 生成一个注册器
45    @register.filter # 注册到语法库,过滤语法 ,就是把数据输入进来,内部执行后把改变的结果在反回来
6    def alex_upper(value):
7return value.upper()

             1
            from
             django import template

             2
             3 register = template.Library()
 4 5@register.filter
 6def alex_upper(value):
 7return value.upper()
 8 9@register.simple_tag
10def guess_page(current_page,loop_num):
11     offset = abs(current_page - loop_num)
12return offset

    {% 函数名 参数1 参数2 %}
这里是:
    {% guess_page customer_list.number page_num %}

    {% if page_num  == customer_list.number %}
        <li class="active"><a href="?page={{page_num}}">{{page_num}}<span class="sr-only">(current)</span></a></li>
    {% else %}
        <li class=""><a href="?page={{page_num}}">{{page_num}}<span class="sr-only">(current)</span></a></li>
    {% endif %}

            @register.simple_tag
def guess_page(current_page,loop_num):
    offset = abs(current_page - loop_num)
    # 如果绝对值小于2,就返回page_ele
    if offset < 2:
        # 如果当前页码等于循环的页码,则class="active"if current_page == loop_num:
            page_ele = ‘‘‘
            <li class="active"><a href="?page={{%s}}">{{%s}}<span class="sr-only">(current)</span></a></li>
            ‘‘‘%(loop_num,loop_num)
        # 如果当前页码不等于循环的页码,则class=""else:
            page_ele = ‘‘‘
            <li class=""><a href="?page={{%s}}">{{%s}}<span class="sr-only">(current)</span></a></li>
            ‘‘‘%(loop_num,loop_num)return page_ele

             1
            from
             django import template

             2
            from
             django.utils.html import format_html  # 引入format_html模块

             3
             4     register = template.Library()
 5 6    @register.filter
 7    def alex_upper(value):
 8return value.upper()
 910    # @register.simple_tag
11    # def guess_page(current_page,loop_num):
12     #     offset = abs(current_page - loop_num)
13     #     return offset
14    @register.simple_tag
15    def guess_page(current_page,loop_num):
16         offset = abs(int(current_page) - int(loop_num))
17        # 如果绝对值
18if offset < 2:
19if current_page == loop_num:
20                 page_ele = ‘‘‘
21                 <li class="active"><a href="?page=%s">%s<span class="sr-only">(current)</span></a></li>
22‘‘‘%(loop_num,loop_num)23else:
24                 page_ele = ‘‘‘
25                 <li class=""><a href="?page=%s">%s<span class="sr-only">(current)</span></a></li>
26‘‘‘%(loop_num,loop_num)27return format_html(page_ele)

             1
                @register.simple_tag

             2
                def guess_page(current_page,loop_num):

             3         offset = abs(int(current_page) - int(loop_num))
 4        # 如果绝对值
 5if offset < 2:
 6if current_page == loop_num:
 7                 page_ele = ‘‘‘
 8                 <li class="active"><a href="?page=%s">%s<span class="sr-only">(current)</span></a></li>
 9‘‘‘%(loop_num,loop_num)10else:
11                 page_ele = ‘‘‘
12                 <li class=""><a href="?page=%s">%s<span class="sr-only">(current)</span></a></li>
13‘‘‘%(loop_num,loop_num)14return format_html(page_ele)
15else:
16return‘‘