Want to create dynamic field configuration with dropdown

Question

I want to create dynamic field configuration with dropdown , can anyone help me on this.

Answer 1

Use below snippet:

we need to define the field in etc/adminhtml/system.xml

<group id="additional" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
    <label>Additional</label>
    <field id="customfields" translate="label" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
        <label>Dynamic Fields</label>
        <frontend_model>Vendor\Module\Block\Adminhtml\Form\Field\DynamicFields</frontend_model>
        <backend_model>Vendor\Module\Config\Backend\DynamicFields</backend_model>
    </field>
</group>

Vendor/Module/Block/Adminhtml/Form/Field/DynamicFields.php

<?php
namespace Vendor\Module\Block\Adminhtml\Form\Field;

class DynamicFields extends \Magento\Config\Block\System\Config\Form\Field\FieldArray\AbstractFieldArray
{
    /**
     * @var Inputgroup
     */
    protected $_groupRenderer;

    /**
     * Retrieve group column renderer
     *
     * @return Inputgroup
     */
    protected function _getGroupRenderer()
    {
        if (!$this->_groupRenderer) {
            $this->_groupRenderer = $this->getLayout()->createBlock(
                \Vendor\Module\Block\Adminhtml\Form\Field\DropdownValues::class,
                '',
                ['data' => ['is_render_to_js_template' => true]]
            );
            $this->_groupRenderer->setClass('dropdown_group_select');
        }
        return $this->_groupRenderer;
    }

    /**
     * Prepare to render
     *
     * @return void
     */
    protected function _prepareToRender()
    {
        $this->addColumn('fieldlabel', ['label' => __('Label'), 'class' => 'required-entry']);
        $this->addColumn(
            'dropdown_group_id',
            ['label' => __('Dropdown'),'size' => '130px',
                'renderer' => $this->_getGroupRenderer(), 'class' => 'required-entry']
        );
        $this->_addAfter = false;
        $this->_addButtonLabel = __('Add More Field');
    }

    /**
     * Prepare existing row data object
     *
     * @param \Magento\Framework\DataObject $row
     * @return void
     */
    protected function _prepareArrayRow(\Magento\Framework\DataObject $row)
    {
        $optionExtraAttr = [];
        $optionExtraAttr['option_' . $this->_getGroupRenderer()->calcOptionHash($row->getData('dropdown_group_id'))] =
            'selected="selected"';
        $row->setData(
            'option_extra_attrs',
            $optionExtraAttr
        );
    }
}

Vendor/Module/Block/Adminhtml/Form/Field/DropdownValues.php

Assign your values array in $this->_inputGroups

<?php
namespace Vendor\Module\Block\Adminhtml\Form\Field;

use Magento\Framework\Api\SearchCriteriaBuilder;

/**
 * HTML select element block with customer groups options
 */
class Inputtype extends \Magento\Framework\View\Element\Html\Select
{
    /**
     * Customer groups cache
     *
     * @var array
     */
    private $_inputGroups;

    /**
     * Flag whether to add group all option or no
     *
     * @var bool
     */
    protected $_addGroupAllOption = true;

    /**
     * @var SearchCriteriaBuilder
     */
    protected $searchCriteriaBuilder;

    /**
     * Construct
     *
     * @param \Magento\Framework\View\Element\Context $context
     * @param GroupManagementInterface $groupManagement
     * @param GroupRepositoryInterface $groupRepository
     * @param SearchCriteriaBuilder $searchCriteriaBuilder
     * @param array $data
     */
    public function __construct(
        \Magento\Framework\View\Element\Context $context,
        SearchCriteriaBuilder $searchCriteriaBuilder,
        array $data = []
    ) {
        parent::__construct($context, $data);
        $this->searchCriteriaBuilder = $searchCriteriaBuilder;
    }

    /**
     * Retrieve allowed customer groups
     *
     * @param int $groupId return name by customer group id
     * @return array|string
     */
    protected function _getInputTypes($groupId = null)
    {
        if ($this->_inputGroups === null) {

            // Add your Dropdown values here
            $this->_inputGroups = array('value 1', 'value 2');
        }
        return $this->_inputGroups;
    }

    /**
     * @param string $value
     * @return $this
     */
    public function setInputName($value)
    {
        return $this->setName($value);
    }

    /**
     * Render block HTML
     *
     * @return string
     */
    public function _toHtml()
    {
        if (!$this->getOptions()) {
            foreach ($this->_getInputTypes() as $inputId => $inputLabel) {
                $this->addOption($inputId, addslashes($inputLabel));
            }
        }
        return parent::_toHtml();
    }
}

Vendor/Module/Config/Backend/DynamicFields.php

<?php
namespace Vendor\Module\Config\Backend;

use Magento\Framework\App\Cache\TypeListInterface;
use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Framework\App\Config\Value as ConfigValue;
use Magento\Framework\Data\Collection\AbstractDb;
use Magento\Framework\Model\Context;
use Magento\Framework\Model\ResourceModel\AbstractResource;
use Magento\Framework\Registry;
use Magento\Framework\Serialize\SerializerInterface;

/**
 * Backend for serialized array data
 */
class DynamicFields extends \Magento\Framework\App\Config\Value
{
    /**
     * Json Serializer
     *
     * @var SerializerInterface
     */
    protected $serializer;

    /**
     * ShippingMethods constructor
     *
     * @param SerializerInterface $serializer
     * @param Context $context
     * @param Registry $registry
     * @param ScopeConfigInterface $config
     * @param TypeListInterface $cacheTypeList
     * @param AbstractResource|null $resource
     * @param AbstractDb|null $resourceCollection
     * @param array $data
     */
    public function __construct(
        SerializerInterface $serializer,
        Context $context,
        Registry $registry,
        ScopeConfigInterface $config,
        TypeListInterface $cacheTypeList,
        AbstractResource $resource = null,
        AbstractDb $resourceCollection = null,
        array $data = []
    ) {
        $this->serializer = $serializer;
        parent::__construct($context, $registry, $config, $cacheTypeList, $resource, $resourceCollection, $data);
    }

    /**
     * Prepare data before save
     *
     * @return void
     */
    public function beforeSave()
    {
        /** @var array $value */
        $value = $this->getValue();
        unset($value['__empty']);
        $encodedValue = $this->serializer->serialize($value);

        $this->setValue($encodedValue);
    }

    /**
     * Process data after load
     *
     * @return void
     */
    protected function _afterLoad()
    {
        /** @var string $value */
        $value = $this->getValue();
        if($value){
            $decodedValue = $this->serializer->unserialize($value);
            $this->setValue($decodedValue);
        }
    }
}

Answer 2

I need a custom dropdown, because I have many options how do we put a search filter into the dropdown?