This function returns next element in array after your key or false if it last or key doesn't exists in array.
<?php
function nextElement(array $array, $currentKey)
{
if (!isset($array[$currentKey])) {
return false;
}
$nextElement = false;
foreach ($array as $key => $item) {
$nextElement = next($array);
if ($key == $currentKey) {
break;
}
}
return $nextElement;
}