PHP magic method __invoke, empty instance variables

Question

I'm facing a problem when calling __invoke() on an object. Is __invoke() method agnostic to instance variables? I need to call __invoke() directly on my templates due to some ZF2 injection to call $this->getView()->render(...) (otherwise getView() returns null) and I would like to have instance variables setted there. Any workaround?

See my code:

namespace Person\Person\View\Helper;


use Zend\View\Helper\AbstractHelper;

class PersonShowWidget extends AbstractHelper
{

    protected $model = null;

    public function __construct(array $options = null)
    {
        $this->parseOptions($options);
    }

    public function __invoke()
    {

        var_dump($this->model); //returns null
        return $this->getView()->render('person/show/show_widget', array(
                'title' => 'Cliente',
                'model' => $this->model,
            )
        );
    }

    public function setOptions(array $options = null)
    {
        $this->parseOptions($options);
    }

    protected function parseOptions(array $options = null)
    {
        if (!is_null($options) && is_array($options)) {
            if (isset($options['model'])) {
                $model = $options['model'];
                if (isset($model['id'])) {
                    $this->model['id'] = $model['id'];
                } else {
                    throw new \Exception;
                }
                if (isset($model['form'])) {
                    $this->model['form'] = $model['form'];
                } else {
                    throw new \Exception;
                }
            }
        }

        var_dump($this->model); //returns valid data

    }
}

I do have called the constructor with some options or the setOptions method before calling __invoke().

Thanks,

Answer 1

You have to initialize the view helper with a factory. In this way you can make sure the constructor is called before the __invoke method is called. And no..the __invoke() method is not agnostic to instance variables.

In the Module.php

public function getViewHelperConfig()
{
    return array(
        'factories' => array(
            'personShowWidget' => function ($helpers) {
                $array = array();
                $helper = new Person\Person\View\Helper\PersonShowWidget($array);
                return $helper;
            },
        )
    );
}

Or in the module.config.php

'view_helpers' => array
(
    'factories' => array(
        'personShowWidget' => function ($helpers) {
            $array = array();
            $helper = new Person\Person\View\Helper\PersonShowWidget($array);
            return $helper;
        },
    )
)

Performance-wise you'd better make a Factory class instead of a callable. More info: http://framework.zend.com/manual/2.0/en/modules/zend.module-manager.module-manager.html

Edit:

It seems like you using the ViewHelper wrongly. You don't have to create the instance by yourself. Just use the ViewHelper in the view. So why not just give the $options as parameter to the __invoke method?

public function __invoke(array $options = null)
{
    $this->setOptions($options);

    return $this->getView()->render('person/show/show_widget', array(
            'title' => 'Cliente',
            'model' => $this->model,
        )
    );
}

In the Controller pass the options array to the view:

return array(
    'options' => $options,
);

And call the ViewHelper in the view:

<?php echo $this->personShowWidget($this->options); ?>

Remember: In this way you don't need a Factory to init the ViewHelper. Just add it to the invokables.

module.config.php example:

'view_helpers' => array(
    'invokables' => array(
        'personShowWidget' => 'Person\Person\View\Helper\PersonShowWidget',
    ),
),