Custom value for list_display item on Django admin

Question

In a model I have a subtitle field, which is populated with None if no value exists for the field for the given object.

Is there any way to display the value to something custom (like Not Available or Not Applicable than just displaying (None)

field

sub_title = models.CharField(max_length=255, null=True, blank=True) 

admin

 list_display = 'sub_title', 

PS: I want None in the database, while a custom value just on admin panel.

thanks

Answer 1

list_display can accept a callable, so you can do this:

class MyModelAdmin(admin.ModelAdmin):
    list_display = ('get_sub_title',)

    def get_sub_title(self, obj):
        if obj.sub_title:
            return obj.sub_title
        else:
            return 'Not Available'

    get_sub_title.short_description = 'Subtitle'

The docs provide several other options for providing a callable.

Answer 2

It would be better if you use empty_value_display

empty_value_display
This attribute overrides the default display value for record’s fields that are empty (None, empty string, etc.). The default value is - (a dash).

class AuthorAdmin(admin.ModelAdmin):
    list_display = ('sub_title',)
    sub_title.empty_value_display = 'Not Available'

This is for django >= 1.9