How to avoid using the Object Manager in Magento2?

Question

From this website:

Manually Load Object Manager

You should avoid calling the object manager directly as this is not the proper way, but if you have to you use:

$om = \Magento\Framework\App\ObjectManager::getInstance();
/* use object manager to get a class for example the attribute repository */
$attr = $om->get('\Magento\Eav\Api\AttributeRepositoryInterface');
/* use returned class attribute repository to get the attribute id of
the name for products */
$productNameAttributeId = $attr->get('catalog_product', 'name')->getId();

It states:

this is not proper way, but if you have to you use

How can I do this the proper way?

Answer 1

The proper way is to use dependency injection in your class constructor:

protected $_attributeRepoInterface;

public function __construct(
    ...
    \Magento\Eav\Api\AttributeRepositoryInterface $attributeRepoInterface
) {
    $this->_attributeRepoInterface = $attributeRepoInterface;
    parent::_construct(...);
}

Then later in your code, you can use the protected variable directly:

$this->_attributeRepoInterface->get('catalog_product','name')->getId();