php - Previous and next link in wordpress for the same category -

in single.php file of wordpress there navigation section link next or previous post. code used previous/next post. these links open same category posts (in example below "2" id of category):

<?php previous_post_link('%link', '<i class="icon-chevron-left pull-left"></i>', true, '2'); ?> <?php next_post_link('%link', '<i class="icon-chevron-right pull-right"></i>', true, '2'); ?> 

why not working?

the fourth parameter categories want exclude, in case you're excluding category 2.

removing fourth parameter should trick:

<?php previous_post_link('%link', '<i class="icon-chevron-left pull-left"></i>', true); ?> <?php next_post_link('%link', '<i class="icon-chevron-right pull-right"></i>', true); ?> 

reference: next_post_link , previous_post_link.

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update

get adjacent post links 1 subcategory not simple, can apply method described in this answer, using filter wp_get_object_terms refer category wanted.

so, having id of category want (in case use 2 example), code put in single.php file:

<?php     // set category id wanted     $globals['just_this_category'] = 2;     // add filter navigation links     add_filter('wp_get_object_terms', 'my_custom_post_navigation'); ?> ?>  <!-- navigation links --> <?php previous_post_link('%link', '<i class="icon-chevron-left pull-left"></i>', true); ?> <?php next_post_link('%link', '<i class="icon-chevron-right pull-right"></i>', true); ?>  <?php // remove filter after navigation links     remove_filter('wp_get_object_terms', 'my_custom_post_navigation'); ?> 

and filter function functions.php file:

function my_custom_post_navigation($terms){     global $just_this_category;      if( array_search($just_this_category, (array)$terms) !== false )          return array($just_this_category);      return array();  } 

as can see used global variable $just_this_category pass category id filter function.

obviously every post need set different category id (you can retrieve automatically, how depends on how manage categories).