Wordpress: Show the parent menu title - php

Question

I want to show the parent menu item above the submenu but when there is no submenu the parent menu item must not be showing then.
Now i use this code (page.php):
<div class="left">
<h2>
<?php
$parent_title = get_the_title($post->post_parent);
echo $parent_title;
?>
</h2>
<?php wp_nav_menu( array('container_class' => 'Hoofdmenu','theme_location' => 'Hoofdmenu','sub_menu' => true) ); ?>
<?php get_sidebar(); ?>
</div>
Output:
TITLE PARENT MENU
Subitem
Subitem
Subitem
------------
Widgets and stuff not important.
But with this code the parent menu item (title) is always visible even when there is no submenu...

Answer 1

Looks like what you need is a combination of checking if the page is a parent or not and then also seeing if it has children.
Something like this should work.
<?php
if ( is_page($post->ID) && $post->post_parent ) {
$children = get_pages('child_of='.$post->post_parent);
} else {
$children = get_pages('child_of='.$post->ID);
}
?>
<?php if($children):?>
<h2>
<?php
$parent_title = get_the_title($post->post_parent);
echo $parent_title;
?>
</h2>
<?php endif;?>

Answer 2

I modified a function from a similar question to get the parent menu title:
Getting the current menu item id from specific menu
function wpse16243_wp_nav_menu_objects( $sorted_menu_items )
{
foreach ( $sorted_menu_items as $menu_item ) {
if ( $menu_item->current ) {
$GLOBALS['current_menu_title']=$menu_item->title;
$GLOBALS['current_menu_ID'] =$menu_item->menu_item_parent;
break;
}
}
foreach ( $sorted_menu_items as $menu_item ) {
if ( $menu_item->ID==$GLOBALS['current_menu_ID'] ) {
$GLOBALS['parent_menu_title'] =$menu_item->title;;
break;
}
}
return $sorted_menu_items;
}
Just use the variable $GLOBALS['current_menu_title']