Next/Previous child page links WordPress

Mark F. comments:

I'm really looking for a way to isolate it to the child pages. I will give this code a try in a bit and see what it does differently than what I am currently using as a work around (the next page plugin). Thank you.

Darrin Boutote comments:

Reinvented the wheel a bit here, but this should work for you. Just add it to your functions.php file:


<?php
// function to find location within array
function relative_value_array($array, $current_val = '', $offset = 1) {
$values = array_values($array);
$current_val_index = array_search($current_val, $values);

if( isset($values[$current_val_index + $offset]) ) {
return $values[$current_val_index + $offset];
}
return false;
};

// previous page link function
function dbdb_prev_page_link() {
global $post;

if ( isset($post->post_parent) && $post->post_parent > 0 ) {
$children = get_pages('&sort_column=post_date&sort_order=asc&child_of='.$post->post_parent.'&parent='.$post->post_parent);
};

// throw the children ids into an array
foreach( $children as $child ) { $child_id_array[] = $child->ID; }

$prev_page_id = relative_value_array($child_id_array, $post->ID, -1);

$output = '';
if( '' != $prev_page_id ) {
$output .= '<a href="' . get_page_link($prev_page_id) . '"> &laquo; '. get_the_title($prev_page_id) . '</a>';
}
return $output;
};

//next page link function
function dbdb_next_page_link() {
global $post;

if ( isset($post->post_parent) && $post->post_parent > 0 ) {
$children = get_pages('&sort_column=post_date&sort_order=asc&child_of='.$post->post_parent.'&parent='.$post->post_parent);
};

// throw the children ids into an array
foreach( $children as $child ) { $child_id_array[] = $child->ID; }

$next_page_id = relative_value_array($child_id_array, $post->ID, 1);

$output = '';
if( '' != $next_page_id ) {
$output .= '<a href="' . get_page_link($next_page_id) . '">'. get_the_title($next_page_id) . ' &raquo;</a>';
}
return $output;
};
?>


And add this to your page template:


<div class="navigation">
<div class="alignleft"><?php echo dbdb_prev_page_link(); ?></div>
<div class="alignright"><?php echo dbdb_next_page_link(); ?></div>
</div>


You can see a working example here: [[LINK href="http://darrinb.com/about/the-services/"]]http://darrinb.com/about/the-services/[[/LINK]]


Darrin Boutote comments:

@pippin: The issue with the script you provided is that a link to a page outside of the sub-page's parent hierarchy will show up. For example if your page structure is like so:

Home
About
- Author
- Site
- Misc

a link to Home or About will show up when you're on the Author page b/c the script you provided is only testing to see whether or not the navigation should appear, not what the navigation should point to, and Mark wants navigation only among the child pages of a particular parent.

Mark F. comments:

You NAILED it. Thank you so much! It seems like it was a bit of a tall order. I figured it was something simple and that I was just missing it!