Lấy bài viết next/previous wordpress - cakedeli

next-post-wp.php

<?php
function install_next_post_sc(){
	$class = 'next_post_';
	global $post;
	$categories = get_the_category($post->ID);
	if(!empty($categories)){
		$category = $categories[0]->term_id;
	} else {
		$category = '';
	}
	if( get_adjacent_post(true, '', false) ) {
		ob_start(); 
		next_post_link( '<div class="'.$class.'">%link</div>', '%title <i class="icon-angle-right"></i>', true);
		$result = ob_get_contents();
		ob_end_clean();
		return $result;
	} else { 
		ob_start(); 
		$last = new WP_Query('page__not_in='.$post->ID.'&cat='.$category.'&posts_per_page=1&order=ASC');$last->the_post();
			echo '<span class="'.$class.'"><a href="' . get_permalink() . '">' . get_the_title() . ' <i class="icon-angle-right"></i> </a></span>';
		wp_reset_query();
		$result = ob_get_contents();
		ob_end_clean();
		return $result;
	}; 
}
add_shortcode( 'next_post_sc', 'install_next_post_sc' );

function install_previous_post_sc(){
	$class = 'previous_post_';
	global $post;
	$categories = get_the_category($post->ID);
	if(!empty($categories)){
		$category = $categories[0]->term_id;
	} else {
		$category = '';
	}
	if( get_adjacent_post(true, '', true) ) { 
		ob_start(); 
		previous_post_link( '<div class="'.$class.'"><i class="icon-angle-left"></i> %link</div>', '%title', true );
		$result = ob_get_contents();
		ob_end_clean();
		return $result;
	} else { 
		ob_start(); 
		$first = new WP_Query('page__not_in='.$post->ID.'&cat='.$category.'&posts_per_page=1&order=DESC'); $first->the_post();
			echo '<div class="'.$class.'"><a href="' . get_permalink() . '"><i class="icon-angle-left"></i> ' . get_the_title() . '</a></div>';
		wp_reset_query();
		$result = ob_get_contents();
		ob_end_clean();
		return $result;
	}

}
add_shortcode( 'previous_post_sc', 'install_previous_post_sc' );