【ワードプレス】投稿画面にメタボックスを追加するテンプレート

metabox-template.php

<?php
/*
Plugin Name: Wp Metabox Template
Version: 0.1-alpha
Description: metabox template
Author: kurozumi
Author URI: http://a-zumi.net
Plugin URI: http://a-zumi.net
Text Domain: wp-metabox
Domain Path: /languages
*/

$meta_box = new WP_Meta_Box();
$meta_box->register();

class WP_Meta_Box {
	
	private $option_name  = "wp_meta_box";
	
	private $menu_slug    = "wp_meta_box_slug";
	
	private $section_id   = "wp_meta_box_section_id";
		
	public function register()
	{
		add_action( 'plugins_loaded', array( $this, 'plugins_loaded' ) );
	}
	
	public function plugins_loaded()
	{
		add_action('admin_init', array($this, 'admin_init'));
	}
	
	public function admin_init()
	{
		add_action('add_meta_boxes', array($this, 'add_meta_boxes'));
		
		add_action('save_post', array($this, 'save_post' ) );
	}
	
	public function add_meta_boxes()
	{
		$post_types = get_post_types();
		
		foreach($post_types as $post_type)
		{
			/**
			 * Add a meta box to an edit form.
			 *
			 * @param string           $id            String for use in the 'id' attribute of tags.
			 * @param string           $title         Title of the meta box.
			 * @param callback         $callback      Function that fills the box with the desired content.
			 * @param string|WP_Screen $screen        Optional. The screen on which to show the box
			 * @param string           $context       Optional. The context within the screen where the boxes
			 * @param string           $priority      Optional. The priority within the context where the boxes
			 * @param array            $callback_args Optional. Data that should be set as the $args property
			 */
			add_meta_box(
				'meta-box-id',
				__('Meta Box Title'),
				array($this, 'add_meta_box'),
				$post_type,
				'normal',
				'default'
			);
		}
	}
	
	public function add_meta_box()
	{
		/**
		 * Add a new section to a settings page.
		 *
		 * @param string $id セクションID
		 * @param string $title セクション名
		 * @param string $callback セクションの説明などを出力するための関数
		 * @param string $page 設定ページのslug ※add_menu_page()の$menu_slugと同じものにする
		 */
		add_settings_section( $this->section_id, "", "", $this->menu_slug );
		
		/**
		 * Add a new field to a section of a settings page
		 *
		 * @param string $id 入力項目ID
		 * @param string $title 入力項目名
		 * @param string $callback 入力項目のHTMLを出力する関数
		 * @param string $page 設定ページのslug ※addd_menu_page()の$menu_slugと同じものにする
		 * @param string $section セクションID add_settings_section()の$idと同じものにする
		 * @param array  $args $callbackの追加引数
		 */
		add_settings_field('message', 'メッセージ', array($this, 'text_callback'), $this->menu_slug, $this->section_id, array('name' => 'message'));
		add_settings_field('message2', 'メッセージ2', array($this, 'text_callback'), $this->menu_slug, $this->section_id, array('name' => 'message2'));
		
		do_settings_sections($this->menu_slug);
	}
	
	public function text_callback($args)
	{
		global $post_id;
		
		$value = get_post_meta($post_id, sprintf("%s_%s", $this->option_name, $args['name']), true);
		?>
		<input type="text" id="<?php _e($args['name']);?>" name="<?php printf("%s[%s]", $this->option_name, $args['name']);?>" value="<?php esc_attr_e($value) ?>" />
		<?php
	}
	
	public function save_post($post_id)
	{
		if(defined('DOING_AUTOSAVE') && DOING_AUTOSAVE)
			return false;
		
		if(!current_user_can('edit_page', $post_id))
			return false;
		
		if(!isset($_POST[$this->option_name]))
			return false;
		
		foreach($_POST[$this->option_name] as $meta_key => $mete_value)
		{
			/**
			 * Update post meta field based on post ID.
			 *
			 * @param int    $post_id    Post ID.
			 * @param string $meta_key   Metadata key.
			 * @param mixed  $meta_value Metadata value. Must be serializable if non-scalar.
			 * @param mixed  $prev_value Optional. Previous value to check before removing.Default empty.
			 */
			update_post_meta(
				$post_id,
				sprintf("%s_%s", $this->option_name, $meta_key),
				$mete_value,
				get_post_meta($post_id, sprintf("%s_%s", $this->option_name, $meta_key), true)
			);
		}		
	}
}