Zend Framework 2: Create Search Widget for Layout

Question

I have a small private Project to learn ZF2. I have integrated Zend Lucene as a Search Function. This works well, but I now want to integrate a Search Field in my Layout, so that it is available on all pages. I am really not sure how to achieve this. First of all, am I correct that this is done with a View Helper? As you can see below, I have got no idea what I have to enter into the __invoke() of my Helper to display my Search Form. Is my way correct in general or is there a better way? I would like a good ZF2 solution, can someone give me some advice? Thank you very much in advance.

Okay, what have I done so far:

1. I created a Form:

namespace Advert\Form;
use Zend\Form\Form;

class SearchForm extends Form
{

  public function __construct()
  {     
    parent::__construct('search');

    $this->setAttribute('method', 'post');

    $this->add(array(
                'name' => 'query',
                'attributes' => array(
                    'type'  => 'text',
                    'id' => 'queryText',
                    'required' => 'required'
                ),
                'options' => array(
                          'label' => 'Search String',
                ),
      ));

            $this->add(array(
                'name' => 'submit',
                'attributes' => array(
                    'type'  => 'submit',
                    'value' => 'Search'
                ),
            ));
      }
}

2. created a View Helper DisplaySearchForm.php !!! 2. UPDATE !!!

A BIG Thank you to AlexP for his help !!!

namespace Advert\View\Helper;
use Zend\View\Helper\AbstractHelper;
use Zend\Form\ElementInterface;

class DisplaySearchForm extends AbstractHelper
{
   protected $form;

   public function __construct($form)
   {
      $this->form = $form;
   }

   public function __invoke($form = null)
   {
      if ($form) {
        $this->form = $form;
      }
      return $this->render($this->form);
   }

   public function render($form)
   {
     // return $this->getView()->form($form);
     // To use my own Style, I have added a Partial
     return $this->getView()->render('partial/search', array('form' => $form));

   } 
}

I read somewhere that it would not be good to use the ServiceLocator in the Helper, so I thought about doing that in a Factory, where I will then get the Form. So I created a Factory (not sure the Factory is right)

3. created Factory

namespace Advert\View\Helper;
use Zend\ServiceManager\FactoryInterface;
use Zend\ServiceManager\ServiceLocatorInterface;

class DisplaySearchFormFactory implements FactoryInterface
{
    public function createService(ServiceLocatorInterface $serviceLocator) {
        $realServiceLocator = $serviceLocator->getServiceLocator();
        $form = $realServiceLocator->get('FormElementManager')->get('\Advert\Form\SearchForm');
        $helper = new DisplaySearchForm($form);
        return $helper;
    } 
}

4. I registered the Factory in the module.php

public function getViewHelperConfig()
{
    return array(
        'factories' => array(
           'displaySearchForm' => 'Advert\View\Helper\DisplaySearchForm',
         )
    )
 }

5. In my Layout layout.phtml

<?php echo $this->displaySearchForm(); ?> 

Answer 1

The AbstractHelper has a getView() which returns the 'renderer'. This means you can use all the view helpers you need, as if you were in a view script.

The new helper could look like this.

use Zend\Form\ElementInterface;

class DisplaySearchForm extends AbstractHelper
{
    protected $element; // Form element to render

    public function __construct(ElementInterface $element)
    {
        $this->element = $element;
    }

    public function __invoke($element = null)
    {
        if ($element) {
            $this->element = $element;
        }
        return $this->render($this->element);
    }

    public function render(ElementInterface $element)
    {
        return $this->getView()->form($element);
    }
}