Extension attributes showing null value in in Magento 2

Question

I have created one custom field in Magento 2 payment table through install schema and want to add getter and setter to the Magento\Quote\Api\Data\PaymentInterface to set and add data.

extension_attributes.xml

<extension_attributes for="Magento\Quote\Api\Data\PaymentInterface">
    <attribute code="policy_no" type="string"/>
</extension_attributes>

When i want to retrieve that value through below code i am getting null.

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
        $paymentInformation = $objectManager->create('Magento\Quote\Api\Data\PaymentInterface');
        $extAttributes = $paymentInformation->getExtensionAttributes();
        var_dump($extAttributes);exit;

Answer 1

You have to setExtensionAttributes manually.

Example:

CustomerRepositoryInterfacePlugin.php

 use Magento\Customer\Api\CustomerRepositoryInterface;
 use Magento\Customer\Api\Data\CustomerExtensionFactory;


class CustomerRepositoryInterfacePlugin
{

[...]
public function __construct(\Psr\Log\LoggerInterface $logger,
                            CustomerExtensionFactory $customerExtensionFactory)
{
    $this->logger = $logger;
    $this->customerExtensionFactory = $customerExtensionFactory;
}

public function afterGetById(CustomerRepositoryInterface $subject,    \Magento\Customer\Api\Data\CustomerInterface $result)
 {
    $extension = $result->getExtensionAttributes() ? $result->getExtensionAttributes() : $this->customerExtensionFactory->create();

    $extension->setCustomAttribute("Custom Attribute");

    $result->setExtensionAttributes($extension);
    return $result;
}
}

di.xml

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
      <type name="Magento\Customer\Api\CustomerRepositoryInterface">
         <plugin name="Namespace-Module" type="Namespace\Module\Plugin\CustomerRepositoryInterfacePlugin" sortOrder="5"/>
     </type>
</config>