get custom post type thumbnail

Question

I need to get the URL for Custom post type Thumbnail, My custom post type name is slider. I have defined on functions.php:

/* Custom post type */
add_action('init', 'slider_register');

function slider_register() {

    $labels = array(
        'name' => __('Slider', 'post type general name'),
        'singular_name' => __('Slider Item', 'post type singular name'),
        'add_new' => __('Add New', 'portfolio item'),
        'add_new_item' => __('Add New Slider Item'),
        'edit_item' => __('Edit Slider Item'),
        'new_item' => __('New Slider Item'),
        'view_item' => __('View Slider Item'),
        'search_items' => __('Search Slider'),
        'not_found' =>  __('Nothing found'),
        'not_found_in_trash' => __('Nothing found in Trash'),
        'parent_item_colon' => ''
    );

    $args = array(
        'labels' => $labels,
        'public' => true,
        'publicly_queryable' => true,
        'show_ui' => true,
        'query_var' => true,
        'menu_icon' => get_stylesheet_directory_uri() . '/image/slider.png',
        'rewrite' => true,
        'capability_type' => 'post',
        'hierarchical' => false,
        'menu_position' => null,
        'supports' => array('title','editor','thumbnail')
        );

    register_post_type( 'slider' , $args );
    flush_rewrite_rules();
}

add_filter("manage_edit-slider_columns", "slider_edit_columns");

function slider_edit_columns($columns){
    $columns = array(
        "cb" => "<input type='checkbox' />;",
        "title" => "Portfolio Title",
    );

    return $columns;
}

My code is:

<!-- Slider -->
<?php
    $args = array(
        'post_type'=> 'post',
        'post_status' => 'publish',
        'order' => 'DESC',
        'tax_query' => array(
            array(
                'post-type' => array('post', 'slider')
            )
        )
    );
    $query = new WP_Query($args);
    if( $query -> have_posts() ) {
?>
    <div id="slider_area">
        <div class="slider">
            <a href='#' class="prev"><i class="fa fa-angle-double-left"></i></a>
            <a href='#' class="next"><i class="fa fa-angle-double-right"></i></a>
            <ul class="slider_list">
                <?php
                    while($query->have_posts()) : $query->the_post();
                        if(has_post_thumbnail()) { ?>
                            <li>
                                <?php the_post_thumbnail(); ?>
                            </li>
                        <?php }
                         elseif($thumbnail = get_post_meta($post->ID, 'image', true)) { ?>
                             <li>
                                 <img src="<?php echo $thumbnail; ?>" alt="<?php the_title(); ?>" title="<?php the_title(); ?>" />
                             </li>
                     <?php } endwhile;
                 ?>
            </ul>
        </div>
    </div>
<?php } ?>

What is the problem? Could anyone help me? Thank you for your helps.

Answer 1

Please update the while loop with this: It will print the thumbnail url for you

** POST FETCHING ARGUMENTS **

<?php 
/**** Slider Call Function ****/
function callTheSlider()
{
    $args = array('post_type'=> 'expro_slider', 'post_status' => 'publish', 'order' => 'DESC');
    ?>
    <ul>
    <?php
    wp_reset_query();
    $query = new WP_Query($args);
    while($query->have_posts()) : $query->the_post();
            if(has_post_thumbnail()) {  ?>
            <li>
                <?php the_post_thumbnail(); ?>
            </li>
        <?php }
        elseif($thumbnail = get_post_meta($post->ID, 'image', true)) { echo 12323; ?>
            <li>
                <img src="<?php echo $thumbnail; ?>" alt="<?php the_title(); ?>" title="<?php the_title(); ?>" />
            </li>
        <?php } endwhile;
        ?>
        </ul>
    <?php
}
?>

Answer 2

You should use

'post_type' => array( 'slider' ),

This is what you should use to display content from a post type named slider not:

'post_type' => 'post',

Answer 3

The following solution worked for me:

$q=new WP_Query(array('post_type'=>'slider', 'post_status' => 'publish', 'order' => 'DESC'));
if($q->have_posts()):
while($q->have_posts()):
$q->the_post(); 
      echo get_the_post_thumbnail_url(get_the_ID(),'full');
endwhile;
endif;

Reference