Gravity Form Custom Hidden Fields

my_custom_field.php

<?php
class My_Custom_Field extends \GF_Field
{
    public $type = 'my_custom_field';

    public function get_form_editor_button()
    {
        return array(
            'group' => 'advanced_fields',
            'text'  => __('My Custom Field', 'gravityforms')
        );
    }

    public function get_form_editor_field_title()
    {
        return __('My Custom Fields', 'gravityforms');
    }

    public function get_form_editor_field_settings()
    {
        return array(
            'label_setting'
        );
    }

    public function get_field_content($value, $force_frontend_label, $form)
    {
        $form_id         = $form['id'];
        $admin_buttons   = $this->get_admin_buttons();
        $field_label     = $this->get_field_label($force_frontend_label, $value);
        $field_id        = is_admin() || $form_id == 0 ? "input_{$this->id}" : 'input_' . $form_id . "_{$this->id}";
        $field_content   = !is_admin() ? '{FIELD}' : $field_content = sprintf("%s<label class='gfield_label' for='%s'>%s</label>{FIELD}", $admin_buttons, $field_id, esc_html($field_label));

        return $field_content;
    }

    public function get_value_entry_detail($value, $currency = '', $use_text = false, $format = 'html', $media = 'screen')
    {
        if (is_array($value)) {
            $items = '';
            foreach ($value as $key => $item) {
                if (!empty($item)) {
                    switch ($format) {
                        case 'text' :
                            $items .= \GFCommon::selection_display($item, $this, $currency, $use_text) . ', ';
                            break;
                        default:
                            $items .= '<li>' . \GFCommon::selection_display( $item, $this, $currency, $use_text ) . '</li>';
                            break;
                    }
                }
            }

            if (empty($items)) {
                return '';
            } elseif ($format == 'text') {
                return substr($items, 0, strlen( $items ) - 2); 
            } else {
                return "<ul class='bulleted'>$items</ul>";
            }
        } else {
            return $value;
        }
    }
}

render_fields.php

<?php
add_filter('gform_field_input', 'render_fields', 10, 5);
function render_fields($input, $field, $value, $entry_id, $form_id)
{
  if ($field->type == 'my_custom_field') {
    $input = '<div class="ginput_complex ginput_container">';

    $i = 1;
    foreach (custom_fields() as $f) {
        $input .= sprintf('<input type="hidden" name="input_%1$s.%2$s" class="%3$s gform_hidden" id="input_%1$s_%4$s_%2$s" value="%5$s" />',
            $field['id'],
            $i,
            esc_attr($f),
            $form_id,
            $value[$field['id'].'.'.$i]
        );

        $i ++;
        if ($i % 10 == 0) {
            $i++;
        }
    }
    $input .= '</div>';
  }
  return $input;
}

set_default_values.php

<?php
add_action('gform_editor_js_set_default_values', set_default_values);
function set_default_values()
{
  ?>
  case 'my_custom_field' :
    field.label = '<?php _e('My Custom Hidden Fields', 'gravityforms'); ?>';
    field.inputs = [
        <?php
        $i = 1;
        foreach (custom_fields() as $f) { ?>
            new Input(field.id + 0.<?php echo $i; ?>, '<?php echo esc_js(__($f, 'gravityforms')); ?>'),
        <?php
            $i++;
            if ($i % 10 == 0) {
                $i++;
            }
        } ?>
    ];
    break;
  <?php
}

unused_gravity_form_functions.php

<?php
add_filter('gform_add_field_buttons', add_field);
function add_field()
{
  foreach ($field_group as &$group) {
    if ($group['name'] == 'advanced_fields') {
      $group['fields'][] = array (
        'class'     => 'button',
        'value'     => __('My Custom Field', 'gravityforms'),
        'onclick'   => "StartAddField('my_custom_field');",
        'data-type' => 'my_custom_field'
      );
      break;
    }
  }
  return $field_group;
}

add_filter('gform_field_type_title', add_field_title, 10, 2);
funciton add_field_title()
{
  if ($field_type == 'my_custom_field') {
    $title = __('My Custom Hidden Fields', 'gravityforms');
  }
  
  return $title;
}

What's a funciton?

HI, i did copy your every file but it's not working