Add media column to edit post screen

Question

I am trying to add a column in the edit post screen that shows any attached media. I found this code to do it with tags, but don't know how to change it to do Media attachments instead.

//add media column to edit post screen
add_action('media_buttons_context','zg_post_buttons');
function add_tag_column($posts_columns) {

 // Add a new column
$posts_columns['att_tag'] = _x('Tags', 'column name');
return $posts_columns;
}

function manage_attachment_tag_column($column_name, $id) {
switch($column_name) {
case 'att_tag':
$tagparent = "upload.php?";
$tags = get_the_tags();
if ( !empty( $tags ) ) {
$out = array();
foreach ( $tags as $c )
$out[] = "<a href='".$tagparent."tag=$c->slug'> " .   
esc_html(sanitize_term_field('name', $c->name, $c->term_id, 'post_tag', 'display')) .  
"</a>";
echo join( ', ', $out );
} else {
_e('No Tags');
}
break;
default:
break;
}

Answer 1

you can create a column of post_thumbnail like so:

// ADDING THUMBNAIL TO EDIT SCREEN
if ( !function_exists('fb_AddThumbColumn') && function_exists('add_theme_support') ) {

    // for post and page
    add_theme_support('post-thumbnails', array( 'post', 'page' ) );

    function fb_AddThumbColumn($cols) {

        $cols['thumbnail'] = __('Thumbnail');

        return $cols;
    }

    function fb_AddThumbValue($column_name, $post_id) {

        $width  = (int) 100;
        $height = (int) 100;

        if ( 'thumbnail' == $column_name ) {
           // thumbnail of WP 2.9
            $thumbnail_id = get_post_meta( $post_id, '_thumbnail_id', true );
            // image from gallery
            $attachments = get_children( array('post_parent' => $post_id, 'post_type' => 'attachment', 'post_mime_type' => 'image') );
            if ($thumbnail_id)
                $thumb = wp_get_attachment_image( $thumbnail_id, array($width, $height), true );
            elseif ($attachments) {
                foreach ( $attachments as $attachment_id => $attachment ) {
                    $thumb = wp_get_attachment_image( $attachment_id, array($width, $height), true );
                }
            }
            if ( isset($thumb) && $thumb ) {
                echo $thumb;
            } else {
                echo __('None');
            }
        }
    }

    // for posts
    add_filter( 'manage_posts_columns', 'fb_AddThumbColumn' );
    add_action( 'manage_posts_custom_column', 'fb_AddThumbValue', 10, 2 );

    // for pages
    add_filter( 'manage_pages_columns', 'fb_AddThumbColumn' );
    add_action( 'manage_pages_custom_column', 'fb_AddThumbValue', 10, 2 );
}

and to add this column to custom post type just add your post type to

add_theme_support('post-thumbnails', array( 'post', 'page','mycustom' ) );

and and action and filter hooks

add_filter( 'manage_mycustom_posts_columns', 'fb_AddThumbColumn' );
add_action( 'manage_mycustom_posts_custom_column', 'fb_AddThumbValue', 10, 2 );

Hope this helps