Django 1.3或更低版本上Django Admin中的自定义过滤器

Question

如何向django admin（模型仪表板右侧显示的过滤器）添加自定义过滤器？我知道很容易包含基于该模型字段的过滤器，但是像这样的“计算”字段呢：

class NewsItem(models.Model):
    headline = models.CharField(max_length=4096, blank=False)
    byline_1 = models.CharField(max_length=4096, blank=True)
    dateline = models.DateTimeField(help_text=_("date/time that appears on article"))
    body_copy = models.TextField(blank=False)

    when_to_publish = models.DateTimeField(verbose_name="When to publish",  blank=True, null=True)

    # HOW CAN I HAVE "is_live" as part of the admin filter?  It's a calculated state!!
    def is_live(self):
        if self.when_to_publish is not None:
            if ( self.when_to_publish < datetime.now() ):
                return """ <img alt="True" src="/media/img/admin/icon-yes.gif"/> """
        else:
            return """ <img alt="False" src="/media/img/admin/icon-no.gif"/> """      

    is_live.allow_tags = True

class NewsItemAdmin(admin.ModelAdmin): form = NewsItemAdminForm list_display = ('headline', 'id', 'is_live') list_filter = ('is_live') # how can i make this work??

Answer 1

感谢gpilotino为我提供了实现正确方向的推动力。

我注意到该问题的代码正在使用datetime来确定其生效时间。因此，我使用了DateFieldFilterSpec并将其子类化。

from django.db import models
from django.contrib.admin.filterspecs import FilterSpec, ChoicesFilterSpec,DateFieldFilterSpec
from django.utils.encoding import smart_unicode
from django.utils.translation import ugettext as _
from datetime import datetime

class IsLiveFilterSpec(DateFieldFilterSpec):
    """
    Adds filtering by future and previous values in the admin
    filter sidebar. Set the is_live_filter filter in the model field attribute
    'is_live_filter'.    my_model_field.is_live_filter = True
    """

    def __init__(self, f, request, params, model, model_admin):
        super(IsLiveFilterSpec, self).__init__(f, request, params, model,
                                               model_admin)
        today = datetime.now()
        self.links = (
            (_('Any'), {}),
            (_('Yes'), {'%s__lte' % self.field.name: str(today),
                       }),
            (_('No'), {'%s__gte' % self.field.name: str(today),
                    }),

        )


    def title(self):
        return "Is Live"

# registering the filter
FilterSpec.filter_specs.insert(0, (lambda f: getattr(f, 'is_live_filter', False),
                               IsLiveFilterSpec))

要使用它，你可以将上面的代码放入filters.py中，并将其导入要添加过滤器的模型中