How can I customize filters in Django admin?

How can I customize filters in Django admin?

You can customize filters in Django admin by creating custom filter classes and registering them with your model admin.

Can you give me an example of a custom filter?

Sure! You can create a custom filter by subclassing admin.SimpleListFilter. For instance, to filter by a specific field value, you can define a filter like this:

from django.contrib import admin

class MyCustomFilter(admin.SimpleListFilter):
    title = 'My Custom Filter'
    parameter_name = 'my_filter'

    def lookups(self, request, model_admin):
        return [('value1', 'Value 1'), ('value2', 'Value 2')]

    def queryset(self, request, queryset):
        if self.value() == 'value1':
            return queryset.filter(my_field='value1')
        if self.value() == 'value2':
            return queryset.filter(my_field='value2')

admin.site.register(MyModel, MyModelAdmin)
MyModelAdmin.list_filter = (MyCustomFilter,)

What if I want to filter by a related model?

You can still use SimpleListFilter for related models. In the queryset method, you can access related fields using Django's ORM. For example:

class RelatedModelFilter(admin.SimpleListFilter):
    title = 'Related Model'
    parameter_name = 'related_model'

    def lookups(self, request, model_admin):
        return [(obj.id, str(obj)) for obj in RelatedModel.objects.all()]

    def queryset(self, request, queryset):
        if self.value():
            return queryset.filter(related_model__id=self.value())
        return queryset