ACF选择父页面的自定义位置规则

答案是…

只需将这些行复制到functions.php中…

感谢John Huebner在ACF论坛上的热心帮助…

add_filter('acf/location/rule_types', 'acf_location_rules_page_grandparent');
function acf_location_rules_page_grandparent($choices) {
    $choices['Page']['page_grandparent'] = 'Page Grandparent';
    return $choices;
}
add_filter('acf/location/rule_values/page_grandparent','acf_location_rules_values_page_grandparent');
function acf_location_rules_values_page_grandparent($choices) {
  // this code is copied directly from 
  // render_location_values() 
  // case "page"
  $groups = acf_get_grouped_posts(array(
    'post_type' => 'page'
  ));
  if (!empty($groups)) {
    foreach(array_keys($groups) as $group_title) {
      $posts = acf_extract_var($groups, $group_title);
      foreach(array_keys($posts) as $post_id) {
        $posts[$post_id] = acf_get_post_title($posts[$post_id]);
      };
      $choices = $posts;
    }
  }
  // end of copy from ACF
  return $choices;
}
add_filter('acf/location/rule_match/page_grandparent', 'acf_location_rules_match_page_grandparent', 10, 3);
function acf_location_rules_match_page_grandparent($match, $rule, $options) {
  // this code is with inspiration from
  // acf_location::rule_match_page_parent()
  // with addition of adding grandparent check
  if(!$options['post_id']) {
    return false;
  }
  $post_grandparent = 0;
  $post = get_post($options['post_id']);
  if ($post->post_parent) {
    $parent = get_post($post->post_parent);
    if ($parent->post_parent) {
      $post_grandparent = $parent->post_parent;
    }
  }
  if (isset($options['page_parent']) && $options['page_parent']) {
    $parent = get_post($options['page_parent']);
    if ($parent->post_parent) {
      $post_grandparent = $parent->post_parent;
    }
  }
  if (!$post_grandparent) {
    return false;
  }
  if ($rule['operator'] == "==") {
    $match = ($post_grandparent == $rule['value']);
  } elseif ($rule['operator'] == "!=") {
    $match = ($post_grandparent != $rule['value']);
  }
  return $match;
}