How to check all items in a loop have post thumbnail?

Question

Currently I have the following loop:

<?php
$shows_sales = get_posts(array(
    'post_type' => 'show_sale',
    'post_status' => 'publish',
    'posts_per_page' => 3,
));
$done_image = false;
?>

<ul>
    <?php foreach ($shows_sales as $post) : setup_postdata($post) ?>
        <?php if (!$done_image && (has_post_thumbnail())) : ?>
            <li class="active">
                <a href="<?php the_permalink() ?>"><?php the_post_thumbnail('homepage'); ?></a>
                <?php $done_image = true; ?>
            </li>   
        <?php else : ?>
            <li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></li>   
        <?php endif; ?>
    <?php endforeach; ?>
    <?php wp_reset_query(); ?>
</ul>

It will show one 'active' list item if post contains featured image, others just show the title in a normal list item.

What I need to add is a check that if none of the posts have a feature image, then insert a list item at the top of the unordered list.

I'm can't get my head around how to say 'if none have post thumbnail then show this else do the above'

Any help would be greatly appreciated!

Answer 1

Before you do your output, do something like this:

$no_thumbnails = true;
foreach( $shows_sales as $p ) {
    if( has_post_thumbnail( $p->ID ) )
        $no_thumbnails = false;
}

Then in your loop you can do something like this:

<?php if( $no_thumbnails === true ) : ?>
    <!-- Your output here -->
<?php endif; ?>

Answer 2

If you need to add the item to the beginning of the list, then you'll need to assemble the HTML before echoing it. Something like this:

<?php
$shows_sales = new WP_Query(array(
    'post_type' => 'show_sale',
    'post_status' => 'publish',
    'posts_per_page' => 3
));
$found_post_thumbnail = false;

// Assemble the HTML for the list items first
$list_items = ''
if ( $shows_sales->have_posts() ) {
    while ( $shows_sales->have_posts() ) {
        $shows_sales->the_post();

        if ( has_post_thumbnail() ) {
            $list_items .= '<li class="active"><a href="' . get_the_permalink() . '">' . get_the_post_thumbnail( 'homepage' ) . '</a></li>';
            $found_post_thumbnail = true;
        } else {
            $list_items .= '<li><a href="' . get_the_permalink() . '">' . get_the_title() . '</a></li>';
        }
    }
}

if ( !$found_post_thumbnail ) {
    $list_items = '<li>THIS IS MY EXTRA LIST ITEM</li>' . $list_items;
}

echo $list_items;
?>

I switched this to a WP_Query request instead of get_posts() plus setup_postdata() - WP_Query is a bit more of a standardized (and nesting-safe) way to do it.