How to update a specific manytomany field in django - django

Question

My Area model has an exercise attribute with a ManyToManyField to my Exercise model:
class Area(models.Model):
name = models.CharField(max_length=100)
exercise = models.ManyToManyField(Exercise)
class Exercise(models.Model):
name = models.CharField(max_length=100)
My AreaView displays a list of areas, which each link to their own list of specific exercises, shown by AreaDetailView:
class AreaView(ListView):
model = Area
template_name = 'workouts/areas.html'
class AreaDetailView(DetailView):
model = Area
template_name = 'workouts/exercises.html'
def get_context_data(self, **kwargs):
context = super(AreaDetailView, self).get_context_data(**kwargs)
context['e_form'] = AddExerciseForm
return context
e.g:
areas.html
- abs
- biceps
- cardio
- legs ...
exercises.html
Abs
- Ab-wheel
- Cable-crunch
- Plank ...
Biceps
- Barbell curl
- Cable curl
- Dumbbell curl
AreaDetailView also displays a form which I would like to allow the user to create their own exercises, which will be specific to their corresponding area.
Here is my form:
class AddExerciseForm(forms.ModelForm):
class Meta:
model = Exercise
fields = ['name']
My template:
<form action="{% url 'exercise_add_new' %}" method="post">
{% csrf_token %}
{{ e_form }}
<button type="submit">Save changes</button>
</form>
My url:
path('exercise-add-new', ExerciseFormView.as_view(), name='exercise_add_new'),
And here is my CreateView which is supposed to handle the logic:
class ExerciseFormView(CreateView):
form_class = AddExerciseForm
success_url = '/'
def form_valid(self, form):
form.save()
new_ex = Exercise.objects.latest('id')
area = Area.objects.get(id=1)
area.exercise.add(new_ex)
return super(ExerciseFormView, self).form_valid(form)
This allows me to update the first object in my Area model ok, but I need to adjust the value of the variable area in form_valid so that the current 'id' is updated. For example if I click on 'Biceps' and then complete the form, I want to add an exercise related to 'id=2'
I have tried area = Area.objects.get(id=self.kwargs['id'])and other similar variations but so far nothing I have tried has worked

Answer 1

In ExerciseFormView are you trying to add a new exercise to an area or create a new area?
If adding a new exercise you will have to pass the area-id from the URL something like add_exercise/<area_id>, if doing the latter it should be straightforward.
You have pass area-id in URL you can do like below
path('exercise-add-new/<int:area_id>/', ExerciseFormView.as_view(),
name='exercise_add_new')
Then update your view as below
def form_valid(self, form):
form.save()
area = Area.objects.get(pk=self.kwargs["area_id"])
new_ex = Exercise.objects.latest('id')
area.exercise.add(new_ex)
return super(ExerciseFormView, self).form_valid(form)
Also update template as :
<form method="post">
{% csrf_token %}
{{ e_form }}
<button type="submit">Save changes</button>
</form>