How to filter model by foreignkey in django's admin forms?

I'm using django 3.2 I have those models. When adding an item to database through django's admin I'd like to be able to after choose the Disciplina (discipline) item, when I'd choose the assunto(subject) the assunto would be filtered by the subjects of the Discipline chosen above. How to do it in pure django (without javascript)?

from django.db import models

# Create your models here.

class Base(models.Model):
    criacao = models.DateTimeField(auto_now_add=True)
    atualizacao = models.DateTimeField(auto_now=True)
    ativo = models.BooleanField(default=True)

    class Meta:
        abstract = True

class Disciplina(Base):
    ORIGEM_CHOICES = [
        ('PT', 'Exame Nacional Português'),
        ('BR', 'ENEM Brasil'),
        ('SUPERIOR', 'Nível Superior'),
    ]

    nome = models.CharField(max_length=100, unique=True)
    origem = models.CharField(max_length=8, choices=ORIGEM_CHOICES)

    def __str__(self):
        return f"{self.nome} ({self.get_origem_display()})"

class Assunto(Base):
    nome = models.CharField(max_length=100)
    disciplina = models.ForeignKey(Disciplina, on_delete=models.CASCADE, related_name='assuntos')

    def __str__(self):
        return f"{self.nome} ({self.disciplina.nome})"

class Questao(Base):
    disciplina = models.ForeignKey(Disciplina, on_delete=models.CASCADE)
    assunto = models.ForeignKey(Assunto, on_delete=models.CASCADE)
    latex_text = models.TextField(blank = True, null=True)  # Novo campo para texto em LaTeX
    math_jax = models.TextField(blank = True, null = True) 
    gabarito = models.CharField(max_length = 200)
    dificuldade = models.CharField(max_length = 10, choices=[
        ('FACIL', 'Fácil'),
        ('MEDIO', 'Médio'),
        ('DIFICIL', 'Difícil'),
    ])
    imagem = models.BooleanField(default = False)
    link_imagem = models.URLField(blank =True, null=True)
    link_bucket = models.URLField(blank = True, null=True)

    def __str__(self):
        return self.latex_text

admin.py

from django.contrib import admin
from .models import Disciplina, Assunto, Questao

@admin.register(Disciplina)
class DisciplinaAdmin(admin.ModelAdmin):
    list_display = ('nome', 'origem')
    search_fields = ('nome',)
    ordering = ('nome',)

@admin.register(Assunto)
class AssuntoAdmin(admin.ModelAdmin):
    list_display = ('nome', 'disciplina_nome')
    search_fields = ('nome',)
    ordering = ('nome',)

    def disciplina_nome(self, obj):
        return obj.disciplina.nome
    disciplina_nome.short_description = 'Disciplina'

@admin.register(Questao)
class QuestaoAdmin(admin.ModelAdmin):
    list_display = ('disciplina_nome', 'assunto_nome', 'latex_text', 'gabarito', 'dificuldade', 'imagem', 'link_imagem')
    search_fields = ('latex_text', 'gabarito')
    ordering = ('disciplina', 'assunto')

    def disciplina_nome(self, obj):
        return obj.disciplina.nome
    disciplina_nome.short_description = 'Disciplina'

    def assunto_nome(self, obj):
        return obj.assunto.nome
    assunto_nome.short_description = 'Assunto'
    

Back to Top