How to add dropdown attribute to custom module in magento 2.0

Question

I wanted to add dropdown attribute called 'customer type' with drop down options 'buyer' and 'seller' to my custom module. How can I make it to my upgrade schema?

Answer 1

Add bellow installation script in your module at path app/code/{Namespace} /{Module-Name}/Setup/InstallData.php

<?php
/**
 * @author      AR
 * @category    AR
 * @package     AR_CustomerAttribute
 */
namespace {Namespace}\{Module-name}\Setup;
use Magento\Customer\Setup\CustomerSetupFactory;
use Magento\Customer\Model\Customer;
use Magento\Eav\Model\Entity\Attribute\Set as AttributeSet;
use Magento\Eav\Model\Entity\Attribute\SetFactory as AttributeSetFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;

/**
 * @codeCoverageIgnore
 */
class InstallData implements InstallDataInterface
{

    /**
     * @var CustomerSetupFactory
     */
    protected $customerSetupFactory;

    /**
     * @var AttributeSetFactory
     */
    private $attributeSetFactory;

    /**
     * @param CustomerSetupFactory $customerSetupFactory
     * @param AttributeSetFactory $attributeSetFactory
     */
    public function __construct(
        CustomerSetupFactory $customerSetupFactory,
        AttributeSetFactory $attributeSetFactory
    ) {
        $this->customerSetupFactory = $customerSetupFactory;
        $this->attributeSetFactory = $attributeSetFactory;
    }


    /**
     * {@inheritdoc}
     */
    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {

        /** @var CustomerSetup $customerSetup */
        $customerSetup = $this->customerSetupFactory->create(['setup' => $setup]);

        $customerEntity = $customerSetup->getEavConfig()->getEntityType('customer');
        $attributeSetId = $customerEntity->getDefaultAttributeSetId();

        /** @var $attributeSet AttributeSet */
        $attributeSet = $this->attributeSetFactory->create();
        $attributeGroupId = $attributeSet->getDefaultGroupId($attributeSetId);

        $customerSetup->addAttribute(Customer::ENTITY, 'customer_type', [

            'type'          => 'static',
            'label'         => 'Customer Type',
            'input'         => 'select',
            'source'        => 'Magento\Eav\Model\Entity\Attribute\Source\Table',
            'required'      => false,
            'sort_order'    => 210,
            'visible'       => false,
            'system'        => false,
            'validate_rules'=> 'a:0:{}',
            'position'      => 210,
            'admin_checkout' => 1,
            'option'         => ['values' => ['Buyer', 'Seller']],
        ]);

        $attribute = $customerSetup->getEavConfig()->getAttribute(Customer::ENTITY, 'customer_type')
        ->addData([
            'attribute_set_id' => $attributeSetId,
            'attribute_group_id' => $attributeGroupId,
            'used_in_forms' => ['adminhtml_customer'],
        ]);

        $attribute->save();


    }
}

See more details

Answer 2

For creating custom attribute through schema, please follow this link. At place of source, you can give options in array OR you can define your own source in custom module.