如何为 Next & Previous post 编写 PHP 条件？

Question

不知道这种情况下if条件语句怎么写？需要一些帮助。如果他们没有任何下一个或上一个帖子可显示，我想完全隐藏 div？并用另一个可用的 div 覆盖剩余的 space。希望这是有道理的。请在下面查看我的最终代码。

<div id="post-navigation">
    
    <?php
        $prev_post = get_previous_post(); 
        $prev_id = $prev_post->ID ;
        $prev_permalink = get_permalink( $prev_id );
        $prev_thumbnail =  get_the_post_thumbnail_url( $prev_id );
        $prev_image_alt = get_post_meta($prev_thumbnail, '_wp_attachment_image_alt', true); 
        $next_post = get_next_post();
        $next_id = $next_post->ID ;
        $next_permalink = get_permalink($next_id);
        $next_thumbnail =  get_the_post_thumbnail_url( $next_id );
        $next_image_alt = get_post_meta($next_thumbnail, '_wp_attachment_image_alt', true);
    ?>
    

    <article class="pexel-previous-post-data has-post-thumbnail pexel-box">
        <div class="pexel-nextPrev-thumbnail">
            <a href="<?php echo $prev_permalink; ?>">
                <img src="<?php echo $prev_thumbnail; ?>" alt="<?php echo $prev_image_alt; ?>" width="200" height="200">
            </a>    
        </div>
        <header class="pexel-previous-post-text">
             <div class="entry-meta before-title prev-next-pill">
                 <span><?php previous_post_link( '%link', __( '<span class="meta-nav">&larr;</span> Previous', 'twentyeleven' ) ); ?> 
                 </span>
             </div>  
            <h5 class="pxl_head--h5 pxl_heading_anim_underline"><a href="<?php echo $prev_permalink; ?>"><?php echo $prev_post->post_title; $short_title; ?></a></h5>
        </header>
    </article>

    <article class="pexel-next-post-data has-post-thumbnail pexel-box">
        <div class="pexel-nextPrev-thumbnail">
            <a href="<?php echo $next_permalink; ?>">
                <img src="<?php echo $next_thumbnail; ?>" alt="<?php echo $next_image_alt; ?>" width="200" height="200">
            </a>    
        </div>
        <header class="pexel-next-post-text">
             <div class="entry-meta before-title next-next-pill">
                 <span><?php next_post_link( '%link', __( 'Next <span class="meta-nav">&rarr;</span>', 'twentyeleven' ) ); ?> 
                 </span>
             </div>  
            <h5 class="pxl_head--h5 pxl_heading_anim_underline"><a href="<?php echo $next_permalink; ?>"><?php echo $next_post->post_title; ?></a></h5>
        </header>
    </article>      

</div>

Answer 1

这里有一个例子，如果没有下一个post，完全隐藏post-navigationdiv。你应该能够从这个例子中找出你想要的其余部分。

这使用了 is_a 函数，因为 get_next_post 要么是 returns 一个空字符串，null，要么是一个 post object 所以如果你检查这个值是否是一个WP_POST 对象，您可以根据需要显示或隐藏 div。永远记得也要转义你的输出。

<?php
$next_post = get_next_post();
// check to see if $next_post is something or nothing.
if ( is_a( $next_post, 'WP_POST' ) ) :
    $next_id        = $next_post->ID;
    $next_permalink = get_permalink( $next_id );
    $next_thumbnail = get_the_post_thumbnail_url( $next_id );
    $next_image_alt = get_post_meta( $next_thumbnail, '_wp_attachment_image_alt', true );
?>
<div id="post-navigation">
    <article class="pexel-next-post-data has-post-thumbnail pexel-box">
        <div class="pexel-nextPrev-thumbnail">
            <a href="<?php echo esc_url( $next_permalink ); ?>">
                <img src="<?php echo esc_url( $next_thumbnail ); ?>" alt="<?php echo esc_attr( $next_image_alt ); ?>" width="200" height="200">
            </a>
        </div>
        <header class="pexel-next-post-text">
            <div class="entry-meta before-title next-next-pill">
                <span><?php next_post_link( '%link', __( 'Next <span class="meta-nav">&rarr;</span>', 'twentyeleven' ) ); ?></span>
            </div>
            <h5 class="pxl_head--h5 pxl_heading_anim_underline">
                <a href="<?php echo esc_url( $next_permalink ); ?>"><?php echo esc_attr( $next_post->post_title ); ?></a>
            </h5>
        </header>
    </article>
</div>
<?php endif; ?>

如何为 Next & Previous post 编写 PHP 条件？

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