Ad Box: Simple way to mark your WordPress posts as ads with one click in your editor

adbox.php

<?php

/** Ad Box **/
/** Author: Adrian Korte, @adkorte **/
/** add this snippet to your functions.php **/
	
	// add a meta box to your edit/new post screen
	add_action( 'add_meta_boxes', 'meta_ad_box_add' );
	function meta_ad_box_add()
	{
		// name and define box and it's appearance
		add_meta_box( 'ad-box-id', 'Werbung', 'meta_ad_box', 'post', 'side', 'high' );
	}
	
	function meta_ad_box($post)
	{
	// $post is already set, and contains an object: the WordPress post
  global $post;
  
  // check if value is set
  $values = get_post_custom( $post->ID );
  $check = isset( $values['meta_ad_box_check'] ) ? esc_attr($values['meta_ad_box_check'][0]) : '';
  
  // We'll use this nonce field later on when saving.
  wp_nonce_field( 'meta_ad_box_nonce', 'meta_ad_box_noncename' );
  
  	// Show checkbox on screen
  	echo (
  		'<input type="checkbox" id="meta_ad_box_check" name="meta_ad_box_check"'. checked($check, 'on', false) .'/>'.
  		'<label for="meta_ad_box_check">Bei diesem Beitrag handelt es sich um Werbung</label>'
  	);
  }
  
  // save values in database
  add_action( 'save_post', 'meta_ad_box_save' );
  function meta_ad_box_save( $post_id )
  {
  	// enable autosave
  	if( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;
  	
  	// if our nonce isn't there, or we can't verify it, bail
  	if( !isset( $_POST['meta_ad_box_noncename'] ) || !wp_verify_nonce( $_POST['meta_ad_box_noncename'], 'meta_ad_box_nonce' ) ) return;
  	
  	// if our current user can't edit this post, bail
  	if( !current_user_can( 'edit_post' ) ) return;
  	
  	// get value of checkbox
  	$chk = isset( $_POST['meta_ad_box_check'] ) ? 'on' : 'off';
  	
  	// save value to database, as post_meta
  	update_post_meta( $post_id, 'meta_ad_box_check', $chk );
  }
?>

call-adbox.php

<?php
/** Call your ad note within your content page **/
/** Use this snippet in your content template files, within the loop **/

  // get value for meta_box
	$adbutton = get_post_meta( get_the_ID(), 'meta_ad_box_check', true );
	// If value is 'on', show hint
	if ( $adbutton == 'on' ) {
		echo "Werbung";
	}
?>