FilterColumnsMixin for adding a button for selecting which columns to show in Django admin changelist

admin.py

from app.forms import FilterColumnsForm
from django.contrib.admin.utils import label_for_field
from django.template.response import TemplateResponse
from django.urls import path
from django.utils.translation import gettext_lazy as _


class FilterColumnsMixin:
    """Allow users to filter the columns in the changelist.
    This will add a "Columns" button to the changelist page to select the columns to display.
    """
    filter_columns_flag = True  # Just a flag to see in template if mixin is present

    def get_list_display(self, request):
        """Filter the list_display based on the form response.
        If session middleware is active, store it per model on current user session.

        When for some reason session is disabled then save it on the class instance itself,
        will be the same for all users and will reset on application restart.
        """
        model_name = self.model._meta.model_name  # pylint: disable=protected-access
        filter_columns = request.GET.getlist('filter_columns')
        is_reset = request.GET.get('reset_columns')

        default_list_display = super().get_list_display(request)
        if hasattr(request, 'session'):
            # In most cases session middleware is used
            if is_reset:
                try:
                    del request.session['filter_columns'][model_name]
                    request.session.modified = True
                except KeyError:
                    pass
            # If all columns are selected, don't store it in session
            elif filter_columns and filter_columns != list(default_list_display):
                request.session['filter_columns'] = {model_name: filter_columns}

            try:
                return request.session['filter_columns'][model_name]
            except (KeyError, TypeError):
                return default_list_display
        else:
            # Fall back to "persisting" on the class instance list_display attribute
            if is_reset:
                self.list_display = default_list_display
            elif filter_columns:
                self.list_display = filter_columns
            return self.list_display

    def get_list_display_links(self, request, list_display):
        """When display link is not in list_display, use the first column as fallback.
        Otherwise, there will be no link to click on.
        """
        result = super().get_list_display_links(request, list_display)
        list_display = self.get_list_display(request)
        if list_display and not [x for x in result if x in list_display]:
            result = list_display[0]
        return result

    def get_urls(self):
        """Adds a intermediary columns page to this admin.
        """
        name = f'{self.model._meta.app_label}_{self.model._meta.model_name}_columns'  # pylint: disable=protected-access
        urls = super().get_urls()
        return [
            path('columns/', self.admin_site.admin_view(self.filter_columns), name=name),
        ] + urls

    def filter_columns(self, request):
        """View for intermediary page when clicking on the "Columns" button.
        Will render an admin view with standard context, showing the `FilterColumnsForm`.
        """
        cl = self.get_changelist_instance(request)

        # Determine which to display in the form and which are already selected
        display = []
        selected = []
        all_fields = type(self).list_display
        for field_name in all_fields:
            text = label_for_field(field_name, cl.model, model_admin=cl.model_admin, return_attr=False)
            display.append((field_name, text))
            if field_name in cl.list_display:
                selected.append(field_name)

        # Initialize form with selected and set the available choices
        form = FilterColumnsForm(initial={'filter_columns': selected})
        form['filter_columns'].field.choices = display

        # Add context for showing the menu and bars
        context = self.admin_site.each_context(request)
        context['title'] = _('Choose which columns to show')
        context['form'] = form
        context['opts'] = self.model._meta  # pylint: disable=protected-access
        request.current_app = self.admin_site.name
        return TemplateResponse(request, 'admin/filter_columns.html', context)

change_list.html

{% extends 'admin/change_list.html' %}
{% load i18n admin_urls %}

{% block object-tools-items %}
  {% if cl.pk_attname != 'history_id' %}
  {% url opts|admin_urlname:'changelist_history' as history_url %}
  {% if history_url %}
  <li>
    <a href="{% add_preserved_filters history_url %}" class="historylink">{% translate "History" %}</a>
  </li>
  {% endif %}
  {% endif %}
  {% if cl.model_admin.filter_columns_flag %}
  <li><a href="{% url opts|admin_urlname:'columns' %}">Columns</a></li>
  {% endif %}
  {{ block.super }}
{% endblock %}

filter_columns.html

{% extends 'admin/base_site.html' %}
{% load admin_urls static %}

{% block extrahead %}
  {{ block.super }}
  <link rel="stylesheet" href="{% static "admin/css/forms.css" %}">
  {{ form.media }}
{% endblock %}

{% block content %}
<form action="{% url opts|admin_urlname:'changelist' %}" method="GET">
  {{ form.as_div }}
  <div class="submit-row" style="clear: both">
    <input type="submit" value="OK" class="default">
    <input type="submit" name="reset_columns" value="Reset">
  </div>
</form>
{% endblock %}

forms.py

from django import forms
from django.contrib.admin.widgets import FilteredSelectMultiple


class FilterColumnsForm(forms.Form):
    """Form with only one field to filter the columns.
    Django widget for horizontal selection, works only in the admin and only with media included.
    """
    filter_columns = forms.MultipleChoiceField(
        label=False,
        widget=FilteredSelectMultiple('columns', is_stacked=False)
    )

    class Media:
        js = ('/admin/jsi18n',)