Better ArrayField admin widget? - django

Question

Is there any way to make ArrayField's admin widget allow adding and deleting objects? It seems that by default, it is instead displayed just a text field, and uses comma separation for its values.
Besides being inconvenient, AFAICT in the case the base field of the array is a Char/TextField, this doesn't allow any way of including commas in any of the texts in the array.

Answer 1

I take no credit for this (original source), but if you are using PostgreSQL as the database and are happy to use the Postgres-specific ArrayField implementation there is an even easier option: subclass ArrayField on the model and override the default admin widget. A basic implementation follows (tested in Django 1.9, 1.10, 1.11, 2.0, 2.1 & 2.2):
models.py
from django import forms
from django.db import models
from django.contrib.postgres.fields import ArrayField
class ChoiceArrayField(ArrayField):
"""
A field that allows us to store an array of choices.
Uses Django's Postgres ArrayField
and a MultipleChoiceField for its formfield.
"""
def formfield(self, **kwargs):
defaults = {
'form_class': forms.MultipleChoiceField,
'choices': self.base_field.choices,
}
defaults.update(kwargs)
# Skip our parent's formfield implementation completely as we don't
# care for it.
# pylint:disable=bad-super-call
return super(ArrayField, self).formfield(**defaults)
FUNCTION_CHOICES = (
('0', 'Planning'),
('1', 'Operation'),
('2', 'Reporting'),
)
class FunctionModel(models.Model):
name = models.CharField(max_length=128, unique=True)
function = ChoiceArrayField(
base_field=models.CharField(max_length=256, choices=FUNCTION_CHOICES),
default=list)

Answer 2

For OP, or anyone out there looking, between these helpful bits you should be good to go:
1. Extending SelectMultiple or CheckboxSelectMultiple widget to parse arrayfield and
2. Creating or extending admin form to display the arrayfield using the widget above

Answer 3

This is a better version of an already accepted solution. Using "CheckboxSelectMultiple" makes it more usable in the admin page.
class ChoiceArrayField(ArrayField):
def formfield(self, **kwargs):
defaults = {
'form_class': forms.TypedMultipleChoiceField,
'choices': self.base_field.choices,
'coerce': self.base_field.to_python,
'widget': forms.CheckboxSelectMultiple,
}
defaults.update(kwargs)
return super(ArrayField, self).formfield(**defaults)

Answer 4

The Django better admin ArrayField package provides exactly this functionality. The advantage over the solutions above is that it allows you to add new entries dynamically instead of relying on pre-defined choices.
See the documentation here: django-better-admin-arrayfield
It has a drop-in replacement for the ArrayField and a simple mixin to add to the admin model.
# models.py
from django_better_admin_arrayfield.models.fields import ArrayField
class MyModel(models.Model):
my_array_field = ArrayField(models.IntegerField(), null=True, blank=True)
# admin.py
from django_better_admin_arrayfield.admin.mixins import DynamicArrayMixin
#admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin, DynamicArrayMixin):
...
This would show something like:

Answer 5

This is another version using the Django Admin M2M filter_horizontal widget, instead of the standard HTML select multiple.
We use Django forms only in the Admin site, and this works for us, but the admin widget FilteredSelectMultiple probably will break if used outside the Admin. An alternative would be overriding the ModelAdmin.get_form to instantiate the proper form class and widget for the array field. The ModelAdmin.formfields_overrides is not enough because you need to instantiate the widget setting the positional arguments as shown in the code snippet.
from django.contrib.admin.widgets import FilteredSelectMultiple
from django.contrib.postgres.fields import ArrayField
from django.forms import MultipleChoiceField
class ChoiceArrayField(ArrayField):
"""
A choices ArrayField that uses the `horizontal_filter` style of an M2M in the Admin
Usage::
class MyModel(models.Model):
tags = ChoiceArrayField(
models.TextField(choices=TAG_CHOICES),
verbose_name="Tags",
help_text="Some tags help",
blank=True,
default=list,
)
"""
def formfield(self, **kwargs):
widget = FilteredSelectMultiple(self.verbose_name, False)
defaults = {
"form_class": MultipleChoiceField,
"widget": widget,
"choices": self.base_field.choices,
}
defaults.update(kwargs)
# Skip our parent's formfield implementation completely as we don't
# care for it.
return super(ArrayField, self).formfield(**defaults)

Answer 6

django-select2 offers a way to render the ArrayField using Select2. In their documentation, the example is for ArrayField:
http://django-select2.readthedocs.io/en/latest/django_select2.html#django_select2.forms.Select2TagWidget
To render the already selected values:
class ArrayFieldWidget(Select2TagWidget):
def render_options(self, *args, **kwargs):
try:
selected_choices, = args
except ValueError: # Signature contained `choices` prior to Django 1.10
choices, selected_choices = args
output = ['<option></option>' if not self.is_required and not self.allow_multiple_selected else '']
selected_choices = {force_text(v) for v in selected_choices.split(',')}
choices = {(v, v) for v in selected_choices}
for option_value, option_label in choices:
output.append(self.render_option(selected_choices, option_value, option_label))
return '\n'.join(output)
def value_from_datadict(self, data, files, name):
values = super().value_from_datadict(data, files, name)
return ",".join(values)
To add the widget to your form:
class MyForm(ModelForm):
class Meta:
fields = ['my_array_field']
widgets = {
'my_array_field': ArrayFieldWidget
}

Answer 7

write a form class for your model and use forms.MultipleChoiceField for ArrayField:
class ModelForm(forms.ModelForm):
my_array_field = forms.MultipleChoiceField(
choices=[1, 2, 3]
)
class Meta:
exclude = ()
model = Model
use ModelForm in your admin class:
class ModelAdmin(admin.ModelAdmin):
form = ModelForm
exclude = ()
fields = (
'my_array_field',
)