Adds hidden field type to Advanced Custom Fields

README

1 - Create folders:

~$ mkdir -p acf-field-hidden/includes

2 - Copy "acf-field-hidden.php", into "acf-field-hidden" folder

3 - Copy "class-acf-field-hidden.php", into "includes" folder

4 - Active the plugin

acf-field-hidden.php

<?php

/**
 * Plugin Name:       Hidden Field for ACF
 * Plugin URI:        https://gist.github.com/allyssonharry/6b46281c4ee2a1a16d1ecfe10c7eac13
 * Description:       Adds hidden type field to Advanced Custom Fields.
 * Author:            Allysson M
 * Text Domain:       acf-field-hidden
 * Domain Path:       /languages
 * Version:           0.1.0
 * Requires PHP:      7.3
 */

defined('ABSPATH') || exit;

/**
 * Define constants
 */
const ACF_MINIMUM_VERSION = '5.0.0';

/**
 * Load text domain
 */
// load_plugin_textdomain( 'acf-field-hidden', false, dirname( plugin_basename(__FILE__) ) . '/languages/' );

/**
 * Initialize the plugin
 *
 * @return ACF|void
 */
function register_acf_field_hidden()
{
    if ( !can_load_plugin() ) {
        // Show the admin notice
        add_action( 'admin_init', __NAMESPACE__ . 'show_admin_notice' );

        deactivate_plugins( plugin_basename( __FILE__ ) );

        return;
    }

    include_once dirname( __FILE__ ) . '/includes/class-acf-field-hidden.php';
}

add_action( 'acf/include_field_types', 'register_acf_field_hidden' );

/**
 * Show admin notice to admins if this plugin is active but either ACF are not active
 *
 * @return bool
 */
function show_admin_notice()
{
    /**
     * For users with lower capabilities, don't show the notice
     */
    if ( !current_user_can('manage_options') ) {
        return false;
    }

    add_action('admin_notices', function () {
        ?>
        <div class="error notice">
            <p><?php esc_html_e(sprintf('Advanced Custom Fields v5.0+ must be active for "acf-field-hidden" to work.', ACF_MINIMUM_VERSION), 'acf-field-hidden');?></p>
        </div>
        <?php
    });
}

/**
 * Check whether ACF are active, and whether the minimum version requirement has been met
 *
 * @return bool
 */
function can_load_plugin()
{
    if ( !class_exists('ACF') ) {
        return false;
    }

    if ( version_compare(get_option('acf_version'), ACF_MINIMUM_VERSION, '<=') ) {
        return false;
    }

    return true;
}

class-acf-field-hidden.php

<?php

/**
 * Register field hidden type
 */
class acf_field_hidden_register extends acf_field
{
    public function __construct()
    {
        $this->name     = 'acf_hidden';
        $this->label    = __('Hidden', 'acf');
        $this->category = 'basic';
        $this->defaults = [
            'default_value' => '',
        ];

        parent::__construct();
    }

    public function prepare_field($field)
    {
        $field['wrapper']['class'] = 'acf-hidden';

        return $field;
    }

    public function render_field($field)
    {
        ?>
            <input type="hidden" name="<?php echo esc_attr($field['name']) ?>" value="<?php echo esc_attr($field['value']) ?>" />
        <?php

    }

    public function render_field_settings($field)
    {
        acf_render_field_setting($field, [
            'label'        => __('Value', 'acf'),
            'instructions' => __('Default value in the hidden input', 'acf'),
            'type'         => 'text',
            'name'         => 'default_value',
        ]);
    }
}

acf_register_field_type('acf_field_hidden_register');