Custom Form Elements and View Helpers for Zend Framework 2

ExFormElement.php

<?php

namespace Admin\Form\View\Helper;

use Zend\Form\ElementInterface;
use Zend\Form\View\Helper\FormElement;

class ExFormElement extends FormElement
{
    /**
     * Overrides method to render an element.
     *
     * Uses a custom view helper if defined by element.
     * Else, go back to parent render method.
     *
     * @param  ElementInterface $element
     * @return string
     */
    public function render(ElementInterface $element)
    {
        if ($element instanceof ExFormElementInterface) {
            $renderer = $this->getView();
            if (!method_exists($renderer, 'plugin')) {
                // Bail early if renderer is not pluggable
                return '';
            }
            $helper = $renderer->plugin( $element->getViewHelperName() );
            return $helper($element);
        }

        return parent::render($element);
    }
}

ExFormElementInterface.php

<?php

namespace Admin\Form\View\Helper;

interface ExFormElementInterface
{
    public function getViewHelperName();
}

Module.php

// ... //

    public function getViewHelperConfig()
    {
        return array(
            'factories' => array(
                'exFormElement' => function($sm) {
                    $helper = new ExFormElement;
                    return $helper;
                },
                'Admin\Form\View\Helper\FormFile' => function($sm) {
                    $helper = new \Admin\Form\View\Helper\FormFile;
                    return $helper;
                }
            )
        );
   }

// ... //