Simple list filter on related models in Django Admin

We have simple model:

class Author(models.Model):
    name = models.CharField(max_length=64)
    is_czech = models.BooleanField()

class Book(models.Model):
    title = models.CharField(max_length=64)
    author = models.ForeignKey(Author)

Create simple list filter class

class AuthorsNacionalityFilter(admin.SimpleListFilter):
    title = _("Author's nacionalyty")
    parameter_name = 'authors_nacionality'

    def lookups(self, request, model_admin):
        return (
            ('czech', _('Czech')),
            ('other', _('Others')),
        )

    def queryset(self, request, queryset):
        if self.value() == 'czech':
            return queryset.filter(author__is_czech=True)
        if self.value() == 'other':
            return queryset.filter(author__is_czech=False)
        return queryset

And use in ModelAdmin:

class BookAdmin(models.ModelAdmin):
    list_filter = (
        AuthorsNacionalityFilter,
    )

Ondrej Sika

Simple list filter on related models in Django Admin