Magento – How to send data from custom fields to a function in admin customer edit

I have added a custom field in Magento Admin Customer edit section and want to send that value to custom function. But not sure how to do this?

I have followed this tutorial – https://webkul.com/blog/tab-with-form-in-admin-customer-edit-magento-2-0/

Below is my code –

<?php
namespace MyCustom\Customadmin\Block\Adminhtml\Customer\Edit;

use Magento\Customer\Controller\RegistryConstants;
use Magento\Ui\Component\Layout\Tabs\TabInterface;
use Magento\Backend\Block\Widget\Form;
use Magento\Backend\Block\Widget\Form\Generic;
/**
 * Customer account form block
 */
class Tabs extends Generic implements TabInterface
{
    protected $_systemStore;
    protected $_coreRegistry;

    public function __construct(
        \Magento\Backend\Block\Template\Context $context,
        \Magento\Framework\Registry $registry,
        \Magento\Framework\Data\FormFactory $formFactory,
        \Magento\Store\Model\System\Store $systemStore,

        array $data = []
    ) {
        $this->_coreRegistry = $registry;
        $this->_systemStore = $systemStore;
        parent::__construct($context, $registry, $formFactory, $data);
    }

    public function getCustomerId()
    {
        return $this->_coreRegistry->registry(RegistryConstants::CURRENT_CUSTOMER_ID);
    }

    public function getTabLabel()
    {
        return __('Password Change');
    }

    public function getTabTitle()
    {
        return __('Password Change');
    }

    public function canShowTab()
    {
        if ($this->getCustomerId()) {
            return true;
        }
        return false;
    }

    public function isHidden()
    {
       if ($this->getCustomerId()) {
            return false;
        }
        return true;
    }

    public function getTabClass()
    {
        return '';
    }

    public function getTabUrl()
    {
        return '';
    }

    public function isAjaxLoaded()
    {
        return false;
    }
    public function initForm($rowcom)
    {
        if (!$this->canShowTab()) {
            return $this;
        }
        /**@var \Magento\Framework\Data\Form $form */
        $form = $this->_formFactory->create();
        $form->setHtmlIdPrefix('myform_');

        $fieldset = $form->addFieldset('base_fieldset', ['legend' => __('Password Change')]);

            $fieldset->addField(
                'demo_field',
                'text',
                [
                    'name' => 'demo_field',
                    'data-form-part' => $this->getData('target_form'),
                    'label' => __('Enter New Password'),
                    'title' => __('Enter New Password'),
                    'value' => $rowcom,
                ]
            );
        $this->setForm($form);
        return $this;
    }

    protected function _toHtml()
    {
        if ($this->canShowTab()) {
            $this->initForm('test test ');
            return parent::_toHtml();
        } else {
            return '';
        }
    }

}

Here I am passing value to $this->initForm('test test ');

But I want that user should ad this value and this store in the database. How can we do this?

I want to set that textbox value as customer password.

public function setPassword(){
        $customerId = $this->_coreRegistry->registry(RegistryConstants::CURRENT_CUSTOMER_ID);
        $password = 'testpassword@123';

        $customer = $customerRepository->getById($customerId);
        $random = $objectManager->get('Magento\Framework\Math\Random');
        $newPasswordToken = $random->getUniqueHash();
        $customerSecure = $customerRegistry->retrieveSecureData($customer->getId());
        $customerSecure->setRpToken($newPasswordToken);
        $customerSecure->setRpTokenCreatedAt((new \DateTime())->format(\Magento\Framework\Stdlib\DateTime::DATETIME_PHP_FORMAT));
        $customerSecure->setPasswordHash($encryptor->getHash($password, true));
        $customerRepository->save($customer);
    }

Edit

Override Save.php –

Location – MyCustom/Customadmin/Controller/Adminhtml/Index/Save.php

<?php
namespace MyCustom\Customadmin\Controller\Adminhtml\Index;

use Magento\Customer\Api\AddressMetadataInterface;
use Magento\Customer\Api\CustomerMetadataInterface;
use Magento\Customer\Api\Data\CustomerInterface;
use Magento\Customer\Controller\RegistryConstants;
use Magento\Customer\Model\EmailNotificationInterface;
use Magento\Customer\Model\Metadata\Form;
use Magento\Framework\Exception\LocalizedException;

class Save extends \Magento\Customer\Controller\Adminhtml\Index\Save
{
    private $emailNotification;

    public function execute()
    {
        $returnToEdit = false;
        $originalRequestData = $this->getRequest()->getPostValue();

        $customerId = $this->getCurrentCustomerId();

        if ($originalRequestData) {
            try {
                // optional fields might be set in request for future processing by observers in other modules
                $customerData = $this->_extractCustomerData();
                $addressesData = $this->_extractCustomerAddressData($customerData);

                if ($customerId) {
                    $currentCustomer = $this->_customerRepository->getById($customerId);
                    $customerData = array_merge(
                        $this->customerMapper->toFlatArray($currentCustomer),
                        $customerData
                        );
                    $customerData['id'] = $customerId;
                }

                /** @var CustomerInterface $customer */
                $customer = $this->customerDataFactory->create();
                $this->dataObjectHelper->populateWithArray(
                    $customer,
                    $customerData,
                    '\Magento\Customer\Api\Data\CustomerInterface'
                    );
                $addresses = [];
                foreach ($addressesData as $addressData) {
                    $region = isset($addressData['region']) ? $addressData['region'] : null;
                    $regionId = isset($addressData['region_id']) ? $addressData['region_id'] : null;
                    $addressData['region'] = [
                    'region' => $region,
                    'region_id' => $regionId,
                    ];
                    $addressDataObject = $this->addressDataFactory->create();
                    $this->dataObjectHelper->populateWithArray(
                        $addressDataObject,
                        $addressData,
                        '\Magento\Customer\Api\Data\AddressInterface'
                        );
                    $addresses[] = $addressDataObject;
                }

                $this->_eventManager->dispatch(
                    'adminhtml_customer_prepare_save',
                    ['customer' => $customer, 'request' => $this->getRequest()]
                    );
                $customer->setAddresses($addresses);
                if (isset($customerData['sendemail_store_id'])) {
                    $customer->setStoreId($customerData['sendemail_store_id']);
                }

                // Save customer
                if ($customerId) {
                    $this->_customerRepository->save($customer);

                    $this->getEmailNotification()->credentialsChanged($customer, $currentCustomer->getEmail());
                } else {
                    $customer = $this->customerAccountManagement->createAccount($customer);
                    $customerId = $customer->getId();
                }

                $isSubscribed = null;
                if ($this->_authorization->isAllowed(null)) {
                    $isSubscribed = $this->getRequest()->getPost('subscription');
                }
                if ($isSubscribed !== null) {
                    if ($isSubscribed !== 'false') {
                        $this->_subscriberFactory->create()->subscribeCustomerById($customerId);
                    } else {
                        $this->_subscriberFactory->create()->unsubscribeCustomerById($customerId);
                    }
                }

                // After save
                $this->_eventManager->dispatch(
                    'adminhtml_customer_save_after',
                    ['customer' => $customer, 'request' => $this->getRequest()]
                    );
                $this->_getSession()->unsCustomerFormData();
                // Done Saving customer, finish save action

                $this->_coreRegistry->register(RegistryConstants::CURRENT_CUSTOMER_ID, $customerId);
                $this->messageManager->addSuccess(__('You saved the customer.'));
                $returnToEdit = (bool)$this->getRequest()->getParam('back', false);
            } catch (\Magento\Framework\Validator\Exception $exception) {
                $messages = $exception->getMessages();
                if (empty($messages)) {
                    $messages = $exception->getMessage();
                }
                $this->_addSessionErrorMessages($messages);
                $this->_getSession()->setCustomerFormData($originalRequestData);
                $returnToEdit = true;
            } catch (LocalizedException $exception) {
                $this->_addSessionErrorMessages($exception->getMessage());
                $this->_getSession()->setCustomerFormData($originalRequestData);
                $returnToEdit = true;
            } catch (\Exception $exception) {
                $this->messageManager->addException($exception, __('Something went wrong while saving the customer.'));
                $this->_getSession()->setCustomerFormData($originalRequestData);
                $returnToEdit = true;
            }
        }
        $resultRedirect = $this->resultRedirectFactory->create();
        if ($returnToEdit) {
            if ($customerId) {
                $resultRedirect->setPath(
                    'customer/*/edit',
                    ['id' => $customerId, '_current' => true]
                    );
            } else {
                $resultRedirect->setPath(
                    'customer/*/new',
                    ['_current' => true]
                    );
            }
        } else {
            $resultRedirect->setPath('customer/index');
        }
        return $resultRedirect;
    }
}