Magento 2.1: Invoke urlBuilder->getUrl() in a controller in a custom module

Question

I think my issue might have to do with dependency injection, which I'm still trying to grab the concept.

What I would like to do is to be able to get the URL using getUrl() function from Magento\Framework\UrlInterface object.

So this what I have so far.

1. Create a functional controller and set up route. It is accessible via web browser and has execute() function defined.
2. Add use Magento\Framework\UrlInterface; in a controller class
3. Add a protected variable $urlBuilder

4. Add a constructor like below

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

The follow error is thrown when I go to the URL that the controller is mapped to.

Fatal error: Uncaught TypeError: Argument 1 passed to Tester\ExamplePaymentGateway\Controller\Example\AbstractExample\Start::__construct() must implement interface Magento\Framework\UrlInterface, instance of Magento\Framework\App\Action\Context given, called in var/generation/Tester/ExamplePaymentGateway/Controller/Example/Start/Interceptor.php on line 14 and defined in app/code/Tester/ExamplePaymentGateway/Controller/Example/AbstractExample/Start.php:24
Stack trace:
#0 var/generation/Tester/ExamplePaymentGateway/Controller/Example/Start/Interceptor.php(14):
Tester\ExamplePaymentGateway\Controller\Example\AbstractExample\Start->__construct(Object(Magento\Framework\App\Action\Context), Object(Magento\Customer\Model\Session\Interceptor), Object(Magento\Checkout\Model\Session\Interceptor), Object(Magento\Sales\Model\OrderFactory), Object(Magento\Paypal\Model\Express\Checkout\Factory), Object(Magento\Framework\Session\Ge in app/code/Tester/ExamplePaymentGateway/Controller/Example/AbstractExample/Start.php on line 24

Am I missing some step before I can inject the URL builder or any other objects (let's say quote, cart, or payment helper)?

Answer 1

If your controller extend Magento\Framework\App\Action\Action you should follow rules of creation of the controller. So you should implement dependency injection of the parent class constructor (Magento\Framework\App\Action\Action):

/**
 * @param Context $context
 */
public function __construct(Context $context)
{
    parent::__construct($context);
    $this->_objectManager = $context->getObjectManager();
    $this->_eventManager = $context->getEventManager();
    $this->_url = $context->getUrl();
    $this->_actionFlag = $context->getActionFlag();
    $this->_redirect = $context->getRedirect();
    $this->_view = $context->getView();
    $this->messageManager = $context->getMessageManager();
}

Your construct method should look like this after a modifications:

/**
 * @param Context $context
 * @param UrlInterface $urlBuilder
 */
public function __construct(
    Context $context,
    UrlInterface $urlBuilder
) {
    parent::__construct($context);
    $this->urlBuilder = $urlBuilder;
}

NOTE: do not forget to remove old var/generation directory after implementing of modifications, because there are stored the generated files of controllers.

Answer 2

actually from controller you can use

$this->_url->getUrl('yourmoduleurl/index/index')