Outputing Post Object title as a div class with ACF

Question

I have Post Object field set up for pages. What I want to do is to output title of the posts associated with the page as a class of the div surrounding the page listing. But, the code inside the foreach loop is not being executed. I've tried with setup_postdata($post) and without, per ACF documentation, the result is always the same.

Here is the code:

function pages() {
$args = array(
    'post_type' => 'page'
    );
$pages = get_posts($args);
    foreach ($pages as $page) {?>
        <div class=" <?php 
            $ancestors = get_field('ancestor');
                foreach ($ancestors as $ancestor) {
                    $class_ancestor_raw = get_the_title($ancestor->ID);
                    $class_ancestor_temp = explode(' ', $class_ancestor_raw);
                    $class_ancestor_str = implode('-', $class_ancestor_temp);
                    $class_ancestor = strtolower($class_ancestor_str);
                    echo $class_ancestor;
                }

        ?>">
            <?php echo $page->post_title; ?>
        </div>
        ?>
    <?php } ?> 

Answer 1

Looks like you're missing the $page->ID from the get_field function.

$ancestors = get_field('ancestor', $page->ID);

Answer 2

You don't pass the page ID to get_field, so you're trying to fetch ancestor for the page you have this code on, not the pages within your foreach.

$ancestors = get_field('ancestor', $page->ID);

You can also simplify your code with the sanitize_title function-

$class_ancestor = sanitize_title( get_the_title($ancestor->ID) );