how to modify choices on admin pages - django

Question

I have a model that has a field named \"state\":

class Foo(models.Model):
    ...
    state = models.IntegerField(choices = STATES)
    ...

Answer 1

This seems like a job for some javascript. You want the list of items in a select box to change depending on the value of something else, which is presumably a checkbox or radio button. The only way to make that happen dynamically - without getting the user to save the form and reload the page - would be with javascript.

You can load custom javascript in a model's admin page by using the ModelAdmin's Media class, documented here.

Answer 2

When you create a new admin interface for a model (e.g. MyModelAdmin) there are specific methods for override the default choices of a field. For a generic choice field:

class MyModelAdmin(admin.ModelAdmin):
    def formfield_for_choice_field(self, db_field, request, **kwargs):
        if db_field.name == "status":
            kwargs['choices'] = (
                ('accepted', 'Accepted'),
                ('denied', 'Denied'),
            )
            if request.user.is_superuser:
                kwargs['choices'] += (('ready', 'Ready for deployment'),)
        return super(MyModelAdmin, self).formfield_for_choice_field(db_field, request, **kwargs)

But you can also override choices for ForeignKey and Many to Many relationships.

Answer 3

You need to use a custom ModelForm in the ModelAdmin class for that model. In the custom ModelForm's __init__ method, you can dynamically set the choices for that field:

class FooForm(forms.ModelForm):
    class Meta:
        model = Foo

    def __init__(self, *args, **kwargs):
        super(FooForm, self).__init__(*args, **kwargs)
        current_state = self.instance.state
        ...construct available_choices based on current state...
        self.fields['state'].choices = available_choices

You'd use it like this:

class FooAdmin(admin.ModelAdmin):
    form = FooForm

Answer 4

I see what you're trying to do, but why not just display all of them and if the person picks the (already set) current state, just don't change anything?

you could also just build a view with a form to provide this functionality