WordPress 自动功能图像代码不起作用

Question

我正在尝试让帖子中的第一个 img 自动成为特色 img 这是我在主题编辑器的 functions.php 中添加的内容

// Auto add featured image
function wpsites_auto_set_featured_image() {
   global $post;
   $featured_image_exists = has_post_thumbnail($post->ID);
      if (!$featured_image_exists)  {
         $attached_image = get_children( "post_parent=$post->ID&post_type=attachment&post_mime_type=image&numberposts=1" );
         if ($attached_image) {
            foreach ($attached_image as $attachment_id => $attachment) {set_post_thumbnail($post->ID, $attachment_id);}
         }
      }
}
add_action('the_post', 'wpsites_auto_set_featured_image');

有什么我需要添加或更改的吗 我对 php 比较陌生

Answer 1

使用 transition_post_status 操作挂钩检查从草稿到发布的过渡，并在此时自动设置特色图像。更新代码：

function wpsites_auto_set_featured_image( $new_status, $old_status, $post ) {
    if ( 'publish' !== $new_status or 'publish' === $old_status ) {
        return;
    }
    if (has_post_thumbnail($post->ID)) {
        return;
    }
    $attached_image = get_children(array(
        'post_parent' => $post->ID,
        'post_type' => 'attachment',
        'post_mime_type' => 'image',
        'numberposts' => 1
    ));
    if ($attached_image) {
        foreach ($attached_image as $attachment_id => $attachment) {
            set_post_thumbnail($post->ID, $attachment_id);
            break;
        }
    }
}
add_action( 'transition_post_status', 'wpsites_auto_set_featured_image', 10, 3 );