How to add a field on Date Formats setting form?

Question

I want to add a field under Localization > Date Formats. What is the correct procedure to do this?

This is what I tried. I added an entry in Localization.settings.php, CRM/Admin/Form/Setting.php's $_settings array property and CRM/Core/Config/MagicMerge.php and, added a corresponding record on civicrm_settings table and cleared the cache. The field is not showing up. What am I missing?

Answer 1

I wouldn't do this by editing core files. I would implement the buildForm and postProcess hooks in a module extension.

https://wiki.civicrm.org/confluence/display/CRMDOC/Create+a+Module+Extension

https://wiki.civicrm.org/confluence/display/CRMDOC/Hook+Reference

But having said that I probably also wouldn't add it to a core form, I would make a settings page for my extension, which is just a module extension that implements the "add a basic web form" instructions at the first link.