Create and pre-populate a mutiple value field in field collection on new node with ajax call

Question

This question is in the same area as a previous I asked (How to create (& pre-populate) multiple “field collection” fields on an ajax call), but with the extra level of complexity that I'm trying to alter a multiple value field inside the field collection.

The Problem

I want to add a number of field instances to a multiple value field, inside a field collection when creating a node using an ajax call.

In order to create and pre-populate a multiple value field collection, you need to change the following value in the AJAX callback and then rebuild the form.

$form_state['field']['--machine-name-of-field-collection--'][LANGUAGE_NONE]['items_count'] = x;

However inside a field collection in $form_state, there is no field information, only entity information. So while I can change item_count for the field collection I can't alter it for any of the fields inside it.

The entity also doesn't seem to be fully created because it's on a brand new node so I can't load it and edit it.

Has anyone encountered this before? How do you work with fields inside entities on forms?

Answer 1

Ok so I didn't manage to solve this directly, but I did accomplish my intent behind this quesion.

The intent behind this was to pre-populate a field collection from another node on a node create form with an ajax call.

I'm still not sure how you alter the fields in a field collection on a form and I'll leave this question open in case anyone knows, however if you're looking to pre-populate field collections onto a node, then this blog post has an answer:

http://drupal.cocomore.com/blog/field-collections-exposed

And I posted an example using ajax to do this in an answer to this question (where I think it's more relevant): How to create (& pre-populate) multiple “field collection” fields on an ajax call