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functions.php 파일 내용 추가

// GET FEATURED IMAGE
function zeein_get_featured_image($post_ID) {
    $post_thumbnail_id = get_post_thumbnail_id($post_ID);
    if ($post_thumbnail_id) {
        $post_thumbnail_img = wp_get_attachment_image_src($post_thumbnail_id, 'thumbnail');
        return $post_thumbnail_img[0];
    }
}

// ADD NEW COLUMN
function zeein_columns_head($defaults) {
    // 일자 전에 추가 할때    
    $ㅜnew = array();
    $defaults['featured_image'] = 'Featured Image';
    $img = $defaults['featured_image'];
    unset($defaults['featured_image']);

    foreach($defaults as $key=>$value ) {
        if ( $key == 'date' ) {
            $new['featured_image'] = $img;
        }
        $new[$key] = $value;
    }

    return $new;

    // 마지막에 추가 할때
    // $defaults['featured_image'] = 'Featured Image';
    // return $defaults;
}

// SHOW THE FEATURED IMAGE
function zeein_columns_content($column_name, $post_ID) {
    if ($column_name == 'featured_image') {
        $post_featured_image = zeein_get_featured_image($post_ID);
        if ($post_featured_image) {
            echo '<img src="' . $post_featured_image . '" />';
        } else {
            echo 'no image';
        }
    }
}

add_filter('manage_posts_columns', 'zeein_columns_head');
add_action('manage_posts_custom_column', 'zeein_columns_content', 10, 2);