django-reorder-items-widget 1.1.1

Easily reorder the order of items within the django admin backend.

Welcome to django-reorder-items-widget

Description

Reorder your items by simply dragging them to their new position. This works fine within django admin's changelists or inline model forms.

All you need to do is to use an editable index field with the famous ReorderItemsWidget of this app.

Installation

Install via pip:

pip install django-reorder-items-widget

Setup

Add reorder_items_widget to your INSTALLED_APPS:

INSTALLED_APPS = [
    'reorder_items_widget',
    ...
]

Add a index field to your model:

class Item(models.Model):
    index = models.PositiveSmallIntegerField()
    ...
    class Meta:
        ordering = ('index',)

Using the ReorderItemsWidget with your index field only makes sense in result lists or inline modeladmin forms. A simple way to put the widget in place is a custom model form:

class ReorderItemForm(forms.ModelForm):
    class Meta:
        widgets={'index': ReorderItemsWidget()}

Now you can use this form with your changelist by overwriting the get_changelist_form method of your model admin:

class BaseItemAdmin(admin.ModelAdmin):
    list_editable = ("index",)
    list_display = ("index", ...)

    def get_changelist_form(self, request, **kwargs):
        kwargs.setdefault('form', ReorderItemForm)
        return super().get_changelist_form(request, **kwargs)

NOTE: Mind that your index field must be editable.

To use the widget with your inline modeladmin simple at your form to the TabularInline class:

class ItemInline(admin.TabularInline):
    form = ReorderItemForm
    fields = ("index", ...)
    ...

That's it.

Caveats

The widget will always number your items sequentially. So reordering a filtered list of items might have unexpected results. Paging however should not be an issue since indexes are updated using the index of the first list item as base.

General considerations on switching index values

There is a general issue with switching values on a unique index field: In mysql like databases you will run into a constraint violation - even if you update all items in a single update transaction.

To work around this you can either obmit the unique constraint. Or implement a complex saving logic like using the negative counterparts of your indexes in a preceding update round and finally switch those values back to their positive equivalent.

Contribute

Feedback, feature requests, bug reports or pull requests are most welcome. Just use the common github infrastructure.