FieldListFilter.register_front = classmethod(_register_front)
class NullListFilter(FieldListFilter):
fields = (models.CharField, models.IntegerField, models.FileField)
def test(cls, field):
return field.null and isinstance(field, cls.fields) and not field._choices
test = classmethod(test)
def __init__(self, field, request, params, model, model_admin, field_path):
self.lookup_kwarg = '%s__isnull' % field.name
self.lookup_val = request.GET.get(self.lookup_kwarg, None)
super(NullListFilter, self).__init__(field, request, params, model, model_admin, field_path)
def expected_parameters(self):
return [self.lookup_kwarg, self.lookup_val]
def choices(self, cl):
# bool(v) must be False for IS NOT NULL and True for IS NULL, but can only be a string
for k, v in ((_('All'), None), (_('Has value'), ''), (_('Omitted'), '1')):
yield {
'selected': self.lookup_val == v,
'query_string': cl.get_query_string({self.lookup_kwarg: v}),
'display': k
}
FieldListFilter.register_front(NullListFilter.test, NullListFilter)
