WordPress Fancy Adjacent Post Links. For use on regular posts or custom post type.

fancy_adjacent_post_link.php

function fancy_adjacent_post_link($prev=false, $iter=1)
{
	global $post;
	
	$link = $title = '';
	
	$a_post = get_adjacent_post( false, '', $prev );
	
	if ($a_post && $a_post->ID > 0)
	{
		$link = get_permalink( $a_post->ID );
		$title = apply_filters('the_title', get_the_title($a_post->ID));
	}
	else
	{
		$order = 'ASC'; 
		if ($prev) { $order = 'DESC'; }
		
		$args = array('post_type' => $post->post_type, 'showposts' => 1, 'order' => $order);
		$p_query = new WP_Query($args);
		if (!empty($p_query->posts)) 
		{
			$link = get_permalink( $p_query->posts[0]->ID );
			$title = apply_filters('the_title', $p_query->posts[0]->post_title); 
		}
		wp_reset_postdata();
	}
	
	if ($link != '' && $title != '') { fancy_adjacent_html($iter, $prev, $link, $title); }
}

function fancy_adjacent_html($iter, $prev, $link, $title)
{
?>
	<li class="col col-2 col-iter-<?php echo $iter; if ($prev) { ?> pagenav-prev<?php } else { ?> pagenav-next<?php } ?>">
		<a href="<?php echo $link; ?>">
			<span><?php echo $title; ?></span>
		</a>
	</li>
<?php
}

// example usage:
<nav class="pagenav">
	<ul>
		<?php fancy_adjacent_post_link(false); ?>
		<?php fancy_adjacent_post_link(true, 2); // previous ?>
	</ul>
</nav>