subhead.php

<?php
/**
 * Handle meta boxes that are used on multiple content types.
 *
 */
class PM_Meta_Boxes {

	private $_blacklisted_post_types = array(
		'pm-best-of',
		'pm-dentists',
		'pm-top-doctors',
	);

	/**
	 * The only instance of the PM_Meta_Boxes object.
	 *
	 * @var PM_Meta_Boxes
	 */
	private static $instance;

	/**
	 * Returns the main instance.
	 *
	 * @return  PM_Meta_Boxes
	 */
	public static function instance() {
		if ( ! isset( self::$instance ) ) {
			self::$instance = new PM_Meta_Boxes;
			self::$instance->setup_actions();
		}

		return self::$instance;
	}

	/**
	 * A dummy constructor.
	 *
	 * @return  PM_Meta_Boxes
	 */
	private function __construct() {}

	/**
	 * Initiate the main actions and filters for meta box related functionality.
	 *
	 * @return  void
	 */
	public function setup_actions() {
		// Add meta boxes
		add_action( 'edit_form_after_title', array( $this, 'subhead' ) );

		// Queues the metabox save actions
		add_action( 'save_post', array( $this, 'save_subhead' ), 10, 2 );
	}
	
	/**
	 * Show subhead field under title field.
	 *
	 * @return  void
	 */
	public function subhead() {
		if ( in_array( get_post_type(), $this->_blacklisted_post_types ) )
			return;

		$subhead = get_post_meta( get_the_ID(), 'pm_subhead', true ) ? get_post_meta( get_the_ID(), 'pm_subhead', true ) : '';
	?>
		<div id="subhead">
			<div id="titlewrap">
				<input type="text" id="pm-subhead" name="pm-subhead" class="widefat" value="<?php echo esc_attr( $subhead ); ?>" placeholder="Enter sub-headline here" />
			</div> <!-- end #titlewrap -->
		</div> <!-- end #subhead -->
	<?php
		wp_nonce_field( 'save', 'pm-subhead-save' );
	}

	/**
	 * Save the subhead value.
	 *
	 * @param	int			$post_id	Post ID.
	 * @param 	object		$post		Post object.
	 * @return	void
	 */
	public function save_subhead( $post_id, $post ) {
		if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
			return;

		if ( ! isset( $_POST['pm-subhead-save'] ) || ! wp_verify_nonce( $_POST['pm-subhead-save'], 'save' ) )
			return;

		if ( ! current_user_can( 'edit_post', $post_id ) )
			return;

		// Save subhead
		if ( isset( $_POST['pm-subhead'] ) && '' !== $_POST['pm-subhead'] )
			update_post_meta( $post_id, 'pm_subhead', wp_kses_post( $_POST['pm-subhead'] ) );
		else
			delete_post_meta( $post_id, 'pm_subhead' );
	}