WPのカスタム投稿一覧表への列（カラム）の追加と並び替え【プラグインなし】

functions.php

function add_column_to_custom_posts($columns){
    $columns['category'] = 'カテゴリー';
    return $columns;
}
add_filter('manage_edit-items_columns', 'add_column_to_custom_posts');

functions.php

function add_content_to_column($column_name, $post_id){
    if($column_name == 'category'){
        $my_terms = get_the_terms($post_id,'items-cate');
        if($my_terms && !is_wp_error($my_terms)){
            $term_name = array();
            foreach ($my_terms as $my_term) {
                $term_name[] = $my_term->name;
            }
            $datas = join(", ", $term_name);
        }
    }
    if(isset($datas) && $datas){
        echo esc_attr($datas);
    }
}
add_action('manage_items_posts_custom_column', 'add_content_to_column', 10, 2);   

functions.php

function add_editor_column_to_custom_posts($columns){
    $columns['author'] = '投稿者';
    return $columns;
}//end function
add_filter('manage_edit-items_columns','add_editor_column_to_custom_posts');

functions.php

function add_thumbnail_column_to_custom_posts($columns){
    $columns['thumbnail'] = 'アイキャッチ';
    return $columns;
}//end function
add_filter('manage_edit-items_columns','add_thumbnail_column_to_custom_posts');

functions.php

function add_content_to_thumbnail_column($column_name,$post_id){
    if($column_name == 'thumbnail'){
        $thumbnail_id  = get_post_thumbnail_id($post_id);
        if($thumbnail_id){
            $thumbnail = wp_get_attachment_image_src($thumbnail_id,'small');
            echo '<img src="' . $thumbnail[0] . '" style="width:100%;max-width:90px;">';
        }else{
            echo esc_html('アイキャッチ画像なし');
        }//end if
    }//end if
}//end function
add_action('manage_items_posts_custom_column','add_content_to_thumbnail_column',10,2);

functions.php

function sort_columns_of_custom_posts($columns){
    $columns = array(
        'thumbnail' => 'サムネイル',//表示名も変更
        'title' => '商品名',//表示名も変更
        'category' => 'カテゴリー',
        'author' => '投稿者名',
        'date' => '日時'
    );
    return $columns;
}
add_filter('manage_edit-items_columns','sort_columns_of_custom_posts');

functions.php

function add_cf_column_to_custom_posts($columns){
    $columns['price'] = '単価';
	$columns['status'] = '販売状態';
	return $columns;
}
add_filter('manage_edit-items_columns','add_cf_column_to_custom_posts');

functions.php

function sort_columns_of_custom_posts($columns){
    $columns = array(
        'thumbnail' => 'サムネイル',
        /*省略*/
        'price' => '単価',//←追記
        'status' => '販売状態',//←追記
        'date' => '日時'
    );
    return $columns;
}
add_filter('manage_edit-items_columns','sort_columns_of_custom_posts');

functions.php

function add_content_to_cf_column($column_name,$post_id){
    if($column_name == 'price' || $column_name == 'status'){
        $metas = get_post_meta($post_id);//postmetaテーブルから$post_idに該当するデータを取得
        $item_cf_str = $metas['item_cf'][0];//カスタムフィールドデータを取得（item_cfは保存時に指定したキー）
        $item_cf_arr = unserialize($item_cf_str);
        $price = $item_cf_arr['price'];
        $status = $item_cf_arr['status'];
    }
    if($column_name == 'price' && isset($price) && $price){
        echo esc_attr($price . "円");
    }
    if($column_name == 'status' && isset($status) && $status){
        $status_ja = "";
        if($status == 'sale'){
            $status_ja = "販売中";
        }elseif($status == 'soldout'){
            $status_ja = "売り切れ";
        }
        echo esc_attr($status_ja);
    }
}
add_action('manage_items_posts_custom_column','add_content_to_cf_column',10,2);    

functions.php

function add_filter_by_column(){
    global $post_type;
    if('items' == $post_type){
        ?>
        <select name="items-cate">
            <option value="">指定なし</option>
        <?php
            $terms = get_terms('items-cate');
            foreach ($terms as $term) { ?>
                <option value="<?php echo $term-<slug; ?>" ?php if ($_GET['items-cate'] == $term->slug){
                    print 'selected';
                } ?>>
                    <?php echo $term->name; ?>
                </option>
                <?php
                }
            ?>
        </select>
        <?php
    }
}
add_action('restrict_manage_posts', 'add_filter_by_column');