Php Don'；不要在wordpress循环中使用上一个和下一个按钮。即使是don'；不要给他们看

使用这个简单的代码。但是按钮不显示。。。奇怪的

<?php

if (have_posts()) :
while (have_posts()) :
  the_post();
     the_content();
previous_posts_link('&laquo; Previous Entries');
next_posts_link('Next Entries &raquo;','');
endwhile;

endif;

?>

<?php
  if (have_posts()) :
    while (have_posts()) :
        the_post();
        the_content();
        if (is_singular('attachment')) {
             // Parent post navigation.
             the_post_navigation(array(
            'prev_text' => _x('<span class="meta-nav">Published in</span><span class="post-title">%title</span>', 'Parent post link', 'themename'),
           ));
          } elseif (is_singular('post')) {
             // Previous/next post navigation.
             the_post_navigation(array(
            'next_text' => '<span class="meta-nav" aria-hidden="true">' . __('Next', 'themename') . '</span> ' .
            '<span class="screen-reader-text">' . __('Next post:', 'themename') . '</span> ' .
            '<span class="post-title">%title</span>',
            'prev_text' => '<span class="meta-nav" aria-hidden="true">' . __('Previous', 'themename') . '</span> ' .
            '<span class="screen-reader-text">' . __('Previous post:', 'themename') . '</span> ' .
            '<span class="post-title">%title</span>',
        ));
     }
  endwhile;
  endif;
?>