Date: Wed, 17 Jan 2007 17:43:10 -0800
From: Rob Thorne < rob@torenware.com>
Subject: [development] "Subclassing" the standard #autocomplete form
        widget
To: development@drupal.org
Message-ID: <45AED0AE.5060806@torenware.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I need a widget for Forms API which *almost* identical to the
textfield autocomplete widget in 5.0.  I want the same user experience
-- the user types and chooses an item.  But I want the underlying AJAX
and Drupal behavior to differ a bit.

An example of the type of widget I'd want would be a "Country Selection"
widget where what I really want is the two-character country code (US,
CA, GB, FR, and so on),  but I want the user to think of typing "United
States",  "Canada", "Great Britain", "France" or so on in order to get
the popup  to get set on this code.

Looking through the 5.0 sources, the way the current autocompletion
widget works is via includes/form.inc,  where the theming function
theme_textfield($element)  special cases textfields with the
'#autocompletion_path' ,  by making sure that autocomplete.js gets added
to the page going out,  and by adding a hidden <item> to store state
information that the code in autocomplete.js needs to do its work.

I really don't need to change behavior very much;  I just need to send
back an array of array(key, value), where the standard widget sends back
an array of string values.  But pretty much everything else that
Unconed's code does exactly what I want, and while I can copy if if
that's easiest, I don't want or need to change what he did.

What's the best way to create my modified Forms API widget?  It looks
like I'd want to "override" or "subclass" theme_textfield, although only
to add behavior:  I don't want standard autocomplete widgets to behave
any different than usual (although I'd not want both sets of code to
compete on the same widget).  I'd then copy autocomplete.js and make
very small changes in it, changing function names where required.

Is there a better way to do this?  Or even better, has someone else
already done this?

Thanks,
Rob

Rob Thorne
Torenware Networks