Feeding a current filter selection to another custom SimpleListFilter in Django

Question

I am trying to make the prompts of one filter change in response to the current selection made in another filter. I am pretty lost as to how to get the currently selected value of the AttributeCategoryFilter passed into the AttributeFilter. I am using Django 1.4-dev. Trying to figure out if I should be using RelatedFieldListFilter for this purpose. It looks like these features are so young as to not have (m)any examples floating around in the wild yet.

    class AttributeCategoryFilter(SimpleListFilter):
        title = _('Attribute Category')
        parameter_name = 'attribute_category'
        def lookups(self, request, model_admin):
            attributes = Attribute.objects.filter(parent_attribute=None)
            prompts = []
            for attribute in attributes:
                prompts.append((attribute.title, _(str(attribute.title))))
            return prompts
        def queryset(self, request, queryset):
            if self.value():
                return queryset.filter(attribute__category=self.value())
            else:
                return queryset


    class AttributeFilter(SimpleListFilter):
        title = _('Attribute Title')
        parameter_name = 'attribute_title'
        def lookups(self, request, model_admin):
            desired_category =  # Needs to be a reference to the selected value in the AttributeCategoryFilter above
            attributes = Attribute.objects.filter(category=desired_category).exclude(parent_attribute=None)
            prompts = []
            for attribute in attributes:
                prompts.append((attribute.title, _(str(attribute.title))))
            return prompts
        def queryset(self, request, queryset):
            if self.value():
                return queryset.filter(attribute__title=self.value())
            else:
                return queryset


    class ValueAdmin(admin.ModelAdmin):
        list_display = ('package', 'attribute', 'presence', 'text', 'modified', 'created')
        list_filter = ('package', AttributeCategoryFilter, AttributeFilter, 'presence', 
            'attribute__admin_approved', 'attribute__dtype', 'modified')
        search_fields = ('package', 'attribute', 'text')
        list_display_links = ('package', )
        list_editable = ('presence', 'text')
        list_per_page = 20000
    admin.site.register(Value, ValueAdmin)   

Answer 1

Found your question as I was looking for something else.

Here's what I did to only show players that had characters in a selected game:

def lookups(self, request, model_admin):
    game_id = request.GET.get('game', None)
    players = Player.objects.all()
    if game_id:
        players = players.filter(character__game_id=game_id)
    return [(p.id, p.__unicode__()) for p in players]

Looks like this is what dan-klasson suggested too.

Hint: Putting ids into query parameters is generally considered a no-no for security reasons.