Custom Form Field Type available for all extensions?

Question

I am making my custom form field types and I would like to make them globally available for all forms everywhere in Joomla.

Is there any certain location that can be used for this purpose, other than libraries/joomla/form/fields, as it is generally considered a bad practice to adding custom files there?

I guess I could manually adding the path in every XML for my custom field, but again it sounds very handy to me if could simply add the fields in a «global scope» like described above.

Answer 1

You can make plugin and use onContentPrepareForm() to add new field to every form possible:

public function onContentPrepareForm($form, $data)
{
    // You can add some filtering here and add fields only to selected components
    if ($form->getName() != 'com_content.article')
    {
        return true;
    }

    // Ensure you're dealing with Form
    if (!($form instanceof JForm))
    {
        $this->_subject->setError('JERROR_NOT_A_FORM');

        return false;
    }

    // If everything is ok - load form file
    JForm::addFormPath(dirname(__FILE__) . '/myform');
    $form->loadFile('myform', false);

    return true;
}

Data from fields added this way is stored in "attribs" column. The only flaw is component must support onContentPrepareForm event. You can also add some custom data handling using onContentDeforeSave() and onContentAfterSave() functions.