wordpress使用文章缩略图

首先检测有没有设置缩略图，如没有则查找文章内容页有无图片，如没有则调用指定图片
functions.php

add_theme_support( 'post-thumbnails' );
function get_post_img_url($thumbnail = true) {
    global $post;   
    if (has_post_thumbnail ()) {
        $domsxe = simplexml_load_string ( get_the_post_thumbnail () );
        $thumbnailsrc = $domsxe->attributes()->src;
        return $thumbnailsrc;       
    }elseif ($thumbnail) {
        $content = $post->post_content;
        preg_match_all ( '/<img.*?(?: |\\t|\\r|\\n)?src=[\'"]?(.+?)[\'"]?(?:(?: |\\t|\\r|\\n)+.*?)?>/sim', $content, $strResult, PREG_PATTERN_ORDER );
        $n = count ( $strResult [1] );
            if ($n > 0) {
                return $strResult [1] [0] ;
            } else {
                return trailingslashit( get_template_directory_uri() ) . 'images/c1.jpg';
            }           
    }else {
        return trailingslashit( get_template_directory_uri() ) . 'images/c1.jpg';
    }
}

页面内调用图片路径

<?php echo get_post_img_url(true); ?>