Django Admin: Using a custom widget for only one model field

I have a DateTimeField field in my model. I wanted to display it as a checkbox widget in the Django admin site. To do this, I created a custom form widget. However, I do not know how to use my custom widget for only this one field.

The Django documentation explains how to use a custom widget for all fields of a certain type:

class StopAdmin(admin.ModelAdmin):
    formfield_overrides = {
        models.DateTimeField: {'widget': ApproveStopWidget }
    }

This is not granular enough though. I want to change it for only one field.

Create a custom ModelForm for your ModelAdmin and add 'widgets' to its Meta class, like so:

class StopAdminForm(forms.ModelForm):
  class Meta:
    model = Stop
    widgets = {
      'approve_ts': ApproveStopWidget(),
    }
    fields = '__all__'

class StopAdmin(admin.ModelAdmin):
  form = StopAdminForm

Done!

Documentation for this is sort of non-intuitively placed in the ModelForm docs, without any mention to it given in the admin docs. See: Creating forms from models

After digging into the admin, model field and form field code, I believe the only way to carry out what I want is by creating a custom model field:

models.py

from django.db import models
from widgets import ApproveStopWidget

class ApproveStopModelField(models.DateTimeField):
    pass

class Stop(models.model):
    # Other fields
    approve_ts = ApproveStopModelField('Approve place', null=True, blank=True)

admin.py

from widgets import ApproveStopWidget
from models import ApproveStopModelField

class StopAdmin(admin.ModelAdmin):
    formfield_overrides = {
        ApproveStopModelField: {'widget': ApproveStopWidget }
    }

It gets the job done.

For the time being, I'll leave the question unanswered because I have the habit of missing the obvious. Perhaps some Django smartypants has a better solution.

Override formfield_for_dbfield like thus:

class VehicleAdmin(admin.ModelAdmin):
    search_fields = ["name", "colour"]

    def formfield_for_dbfield(self, db_field, **kwargs):
        if db_field.name == 'colour':
            kwargs['widget'] = ColourChooserWidget
        return super(VehicleAdmin, self).formfield_for_dbfield(db_field,**kwargs)

(credit to http://www.kryogenix.org/days/2008/03/28/overriding-a-single-field-in-the-django-admin-using-newforms-admin/ )

Django's ModelAdmin.get_changelist_form(self, request, **kwargs) will do the trick for the case of list_editable

class StopAdminForm(forms.ModelForm):
  class Meta:
    model = Stop
    widgets = {
      'approve_ts': ApproveStopWidget(),
    }

class StopAdmin(admin.ModelAdmin):
  form = StopAdminForm

  #just return the ModelForm class StopAdminForm
  def get_changelist_form(self, request, **kwargs):
        return StopAdminForm

Refer to Django Official documentation on this topic

I hope this will help