Many to many fields in widget form - django

Question

I have problem with display many to many field in form widget.
Category is not display in template.
Title is ok (is display) but category isn't - category is empty.
What can I do to display many to many fields in my template form with multiplechoice checkboxes?
Why I cant display article categories in widget form?
MODELS.py
article model:
class Article(Created, HitCountMixin):
title = models.CharField(max_length=120)
author = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
category = models.ManyToManyField(ArticleCategory, related_name='articles')
category model:
class ArticleCategory(Created):
category_name = models.CharField(max_length=128)
slug = models.SlugField(null=False, unique=False)
VIEWS:
class UpdateArticleView(LoginRequiredMixin, UpdateView):
template_name = 'news/update_article.html'
form_class = EditArticleForm
model = Article
def get_success_url(self):
pk = self.kwargs["pk"]
slug = self.kwargs['slug']
return reverse_lazy("news:article_detail", kwargs={'pk': pk, 'slug': slug})
FORMS.py
class AddArticleForm(forms.ModelForm):
title = forms.CharField(
label="Tytuł",
max_length=120,
help_text="Tytuł newsa",
widget=forms.TextInput(attrs={"class": "form-control form-control-lg pr-5 shadow p-1 mb-1 bg-white rounded"}),
required=True,
)
category = forms.MultipleChoiceField(
widget=forms.CheckboxSelectMultiple,
)
And in my HTML TEMPLATE:
<form method="post" enctype='multipart/form-data'>
{% csrf_token %}
{{ form.media }}
{# {% crispy form %}#}
{{ form|crispy }}
<button type="submit" class="btn btn-outline-primary">EDYTUJ NEWS</button>
</form>

Answer 1

Your form_class in your view is a EditArticleForm, so you should be careful to use the correct form.
The form field for a ManyToManyField is normally a ModelMultipleChoiceField [Django-doc], but it is not necessary to specify the form field anyway. You can make use of the widgets option:
class EditArticleForm(forms.ModelForm):
title = forms.CharField(
label='Tytuł',
max_length=120,
help_text='Tytuł newsa',
widget=forms.TextInput(
attrs={'class': 'form-control form-control-lg pr-5 shadow p-1 mb-1 bg-white rounded'}
),
required=True,
)
class Meta:
model = Article
widgets = {
'category': forms.CheckboxSelectMultiple
}
you can customize the label with:
class EditArticleForm(forms.ModelForm):
title = forms.CharField(
label='Tytuł',
max_length=120,
help_text='Tytuł newsa',
widget=forms.TextInput(
attrs={'class': 'form-control form-control-lg pr-5 shadow p-1 mb-1 bg-white rounded'}
),
required=True,
)
class Meta:
model = Article
widgets = {
'category': forms.CheckboxSelectMultiple
}
labels = {
'category': 'label of category'
}