Joomla 4 Upgrade issue with custom component

Question

I have a custom component that I've inherited. I've upgraded the site to Joomla 4 with no problems but when going to the frontend, am getting an error:

Fatal error: Class CloudCardModelCard contains 1 abstract method
and must therefore be declared abstract or
implement the remaining methods
(Joomla\CMS\MVC\Model\ItemModelInterface::getItem) in
public_html/components/com_cloudcard/models/card.php on line 3

The file referenced above is as follows:

<?php defined('_JEXEC') or die;

class CloudCardModelCard extends JModelItem {

}

Any ideas what I can do to get it working?

Answer 1

The ItemModel class (JModelItem) that you are extending with your class CloudCardModelCard is defined as abstract in Joomla 4.

abstract class ItemModel extends BaseDatabaseModel implements ItemModelInterface

However your CloudCardModelCard class is not defined as abstract

class CloudCardModelCard extends JModelItem

Therefore the message is saying you need to change your class statement to

abstract class CloudCardModelCard extends JModelItem

or you need to put all the methods found in ItemModel into your own class, which isn't that big an issue as there is only method to copy

protected function getStoreId($id = '')
{
    // Compile the store id.
    return md5($id);
}

Answer 2

The error is self-explanatory. Your model needs to implement getItem() method required by the Joomla\CMS\MVC\Model\ItemModelInterface interface. This method is meant to be used for retrieving a single content item as an object. If your model already has a similar method named differently (e.g. getCard()), you can proxy getItem() to this method:

public function getItem($pk = null)
{
    return $this->getCard($pk);
}

If your model does not have/need such functionality, consider extending a less specific model such as Joomla\CMS\MVC\Model\BaseDatabaseModel.