下面是一个场景。我必须建立我的客户端，他想用拇指抓取一些类别显示在他的主页上。所以我的路线是，只需找到该类别的第一篇帖子并获取其缩略图，但我不知道如何做到这一点。我遵循了这个准则https://stackoverflow.com/questions/15607840/display-first-last-post-from-each-categories-in-wordpress, 但它将显示所有类别，我不知道如何只提取某些（选定的）类别。

因此，问题是：

我的路线正确吗？或者你可以建议我另一条路线或方法

$categories = get_categories(\'hide_empty=0&orderby=id\');
$include="";

foreach($categories as $category):
    $cat_field = \'rockable_cat_\' . $category->cat_ID;
    if( //some argument return true )   
    $include .= \'<div class="danboru"><a href="\'.get_category_link( $category->term_id ).\'" title="\' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . \'">\'.$category->cat_name.\'</a></div>\';
endforeach;

if($include)
$include = substr($include, 0, -1); //Remove the last comma
return $include;

已解决。。！！这是我的完整代码

从所选类别中获取类别名称

function rockable_build_cat_exclude(){

    $categories = get_categories(\'hide_empty=0&orderby=id\');
    $exclude="";

    foreach($categories as $cat):
    $cat_field = \'rockable_cat_\' . $cat->cat_ID;
    if( get_option($cat_field) and get_option($cat_field)==\'false\')
        $exclude .= "" . $cat->cat_name . ",";      
    endforeach;     

    if($exclude)
    $exclude = substr($exclude, 0, -1); //Remove the last comma


    return $exclude;
}

把它放在前面的代码（index.php）

<?php
$exclude = rockable_build_cat_exclude();
$exclude_array = explode(",",$exclude);

foreach ($exclude_array as $value){
    $cat_query = new WP_Query(array(\'category_name\'=>$value,\'showposts\'=>1));
    if ($cat_query->have_posts()):while($cat_query->have_posts()):$cat_query->the_post();

    $category_id = get_cat_ID( $value );?>
    <div class="danboru">
        <?php the_post_thumbnail(\'home-thumb\');?>
        <a href="<?php get_category_link( $category_id );?>" title="<?php echo esc_attr( sprintf( __( "View all posts in %s" ), $value ) ) ;?>"><?php echo $value;?></a>
    </div>

    <?php endwhile;
    endif;
}

?>

如果您有一些建议或更好的解决方案，请分享您的想法。

$categories = array(1,2,3); // your specific category IDs
$first_thumb = new WP_Query(
  array(
    \'posts_per_page\' => count($categories),
    \'category__in\' => $categories,
    \'meta_query\' => array(
      array(
        \'meta_key\' => \'_thumbnail_id\',
        \'compare\' => \'EXISTS\'
      )
    ),
  )
);
if ($first_thumb->have_posts()) {
  while ($first_thumb->have_posts()) {
    $first_thumb->the_post();
    the_post_thumbnail();
  }
}