I created a custom post type in the mu-plugins folder.

function wpdocs_codex_book_init() {
    $labels = array(
        'name'                  => _x( 'Books', 'Post type general name', 'textdomain' ),
        'singular_name'         => _x( 'book', 'Post type singular name', 'textdomain' ),
    );

    $args = array(
        'labels'             => $labels,
        'public'             => true,
    );

    register_post_type( 'book', $args );
}

add_action( 'init', 'wpdocs_codex_book_init' ); 

When it comes to render the content of it in the single-book.php page I create the custom query and I use this code:

<?php
$args = array(
    'post_type' => 'book',
);
$query = new WP_Query( $args ); 
?>

<h1><?php the_title(); ?></h1>
<h1><?php the_content(); ?></h1>

the title is rendered correctly but when it comes to the content it throws this error:

Warning: count(): Parameter must be an array or an object that implements Countable in /app/public/wp-includes/post-template.php on line 284

The default posts and the pages are, instead, rendered correctly. Why is this happening? Thanks in advance

I created a custom post type in the mu-plugins folder.

function wpdocs_codex_book_init() {
    $labels = array(
        'name'                  => _x( 'Books', 'Post type general name', 'textdomain' ),
        'singular_name'         => _x( 'book', 'Post type singular name', 'textdomain' ),
    );

    $args = array(
        'labels'             => $labels,
        'public'             => true,
    );

    register_post_type( 'book', $args );
}

add_action( 'init', 'wpdocs_codex_book_init' ); 

When it comes to render the content of it in the single-book.php page I create the custom query and I use this code:

<?php
$args = array(
    'post_type' => 'book',
);
$query = new WP_Query( $args ); 
?>

<h1><?php the_title(); ?></h1>
<h1><?php the_content(); ?></h1>

the title is rendered correctly but when it comes to the content it throws this error:

Warning: count(): Parameter must be an array or an object that implements Countable in /app/public/wp-includes/post-template.php on line 284

The default posts and the pages are, instead, rendered correctly. Why is this happening? Thanks in advance

• custom-post-types
• pages
• the-content

• Why are you creating a new query in the template? Does it work correctly if you remove your query code? – Milo Commented Jan 14, 2019 at 13:58
• totally my bad. Wordpress has already identified the correct query since i created the single-book itself. – Enrico Commented Jan 14, 2019 at 14:09

1 Answer 1

single-book.php should not have a custom query in it. WordPress has already queried the correct post, so new WP_Query( $args ) is completely unnecessary.

Your problem is that you're missing the loop.

At the bare minimum single-book.php should have:

<?php while ( have_posts() ) : the_post(); ?>

    <h1><?php the_title(); ?></h1>

    <?php the_content(); ?>

<?php endwhile; ?>