wordpress自定义摘录长度不起作用

I have this code in my functions.php

function custom_excerpt_length() {

return 15;

}

add_filter('excerpt_length', 'custom_excerpt_length');

but it doesn't work as it gives me the full text and not the 15 words I specified. And the grid I have set up on my website is not right because of this.

my movie grid

Thanks in advance

Also use this code for multiple type of getting excerpt

function excerpt($limit) {
      $excerpt = explode(' ', get_the_excerpt(), $limit);
      if (count($excerpt)>=$limit) {
        array_pop($excerpt);
        $excerpt = implode(" ",$excerpt).'...';
      } else {
        $excerpt = implode(" ",$excerpt);
      } 
      $excerpt = preg_replace('`\[[^\]]*\]`','',$excerpt);
      return $excerpt;
    }

    function content($limit) {
      $content = explode(' ', get_the_content(), $limit);
      if (count($content)>=$limit) {
        array_pop($content);
        $content = implode(" ",$content).'...';
      } else {
        $content = implode(" ",$content);
      } 
      $content = preg_replace('/\[.+\]/','', $content);
      $content = apply_filters('the_content', $content); 
      $content = str_replace(']]>', ']]>', $content);
      return $content;
    }

then in your template code you just use..

<?php echo excerpt(25); ?>

Add third parameter and also you have not mention function parameter it will be worked

function custom_excerpt_length( $length ) {
    return 15;
}
add_filter( 'excerpt_length', 'custom_excerpt_length', 999 );