FormHiddenAll.php

<?php
/**
 * Zend Framework (http://framework.zend.com/)
 *
 * @link      http://github.com/zendframework/zf2 for the canonical source repository
 * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd New BSD License
 */

namespace LispBase\Form\View\Helper;

use Zend\Form\View\Helper\AbstractHelper;
use Zend\Form\FieldsetInterface;
use Zend\Form\FormInterface;

/**
 * View helper for rendering hidden elements
 */
class FormHiddenAll extends AbstractHelper
{
    /**
     * All hidden elements
     * @var array
     */
    private $hiddenElements = array();
    
    
    /**
     * Invoke as function
     *
     * @param  null|FormInterface $form
     * @return Form
     */
    public function __invoke(FormInterface $form = null)
    {
        if (!$form) {
            return $this;
        }

        return $this->render($form);
    }

    /**
     * Render all hidden elements
     *
     * @param  FormInterface $form
     * @return string
     */
    public function render(FormInterface $form)
    {

        $this->searchHiddenElements($form->getElements());
        $this->loopFieldsets($form->getFieldsets());
        
        $formContent = '';
        foreach($this->hiddenElements as $element){
            $formContent.= $this->getView()->formHidden($element);
        }

        return $formContent;
    }
    
    private function loopFieldsets($fieldsets){
        foreach($fieldsets as $fieldset){
            $this->searchHiddenElements($fieldset->getElements());
            
            //Fieldsets can also contain fieldsets...so do this recursive...
            $this->loopFieldsets($fieldset->getFieldsets());
        }
    }
    
    private function searchHiddenElements($elements){
        foreach($elements as $element){
            if($element instanceof \Zend\Form\Element\Hidden || $element instanceof \Zend\Form\Element\Csrf){
                $this->hiddenElements[] = $element;
            }
        }
    }
}