getAllItems() foreach is not working?

Question

I want to pass the product info after is ordered and i have created this file for testing. The foreach is not working because it show back just one product and not all of them.

Here is the code:

    $dirPath = Mage::getBaseDir('var') . DS . 'export';

    if (!is_dir($dirPath)) {
        mkdir($dirPath, 0777, true);
    }

    foreach ($order->getAllItems() as $item){

        $data = array(
            'ID'    => $item->getProductId(),
            'QTY'   => $item->getTotalQtyOrdered(),
            'PRICE' => $item->getSubtotal()

            );

    }

    $xml = new SimpleXMLElement('<root/>');
    array_walk_recursive($data, array ($xml, 'addChild'));
    file_put_contents(
    $dirPath. DS .$order->getIncrementId().'.xml', 
    $xml->asXML()

    );

Answer 1

To answer Daniel's additional question in the comment to Marius' answer: use the following code to add items to your XML

$xml = new SimpleXMLElement('<root/>');
foreach ($data as $item) {
    $xmlItem = $xml->addChild('item');
    foreach ($item as $key => $value) {
        $xmlItem->addChild($key, $value);
    }
}
// now you can use file_put_contents()

Answer 2

Wanna bet it works? :) This code

$data = array(
            'ID'    => $item->getProductId(),
            'QTY'   => $item->getTotalQtyOrdered(),
            'PRICE' => $item->getSubtotal()

            );

Should be

$data[] = array(
            'ID'    => $item->getProductId(),
            'QTY'   => $item->getTotalQtyOrdered(),
            'PRICE' => $item->getSubtotal()

            );

It shows you only one product because you keep overwriting the $data variable.