title: Google Drive SDK (PHP) Children: list : the list is empty
body: <p><a href="https://developers.google.com/drive/v2/reference/children/list" rel="nofollow noreferrer">https://developers.google.com/drive/v2/reference/children/list</a></p>
  
  <p>I use this php function taken from the documentation</p>
  
  <pre><code> /**
   * Print files belonging to a folder.
   *
   * @param apiDriveService $service Drive API service instance.
   * @param String $folderId ID of the folder to print files from.
   */
  function printFilesInFolder($service, $folderId) {
    $pageToken = NULL;
  
    do {
      try {
        $parameters = array();
        if ($pageToken) {
          $parameters['pageToken'] = $pageToken;
        }
        $children = $service-&gt;children-&gt;listChildren($folderId, $parameters);
  
        foreach ($children-&gt;getItems() as $child) {
          print 'File Id: ' . $child-&gt;getId();
        }
        $pageToken = $children-&gt;getNextPageToken();
      } catch (Exception $e) {
        print "An error occurred: " . $e-&gt;getMessage();
        $pageToken = NULL;
      }
    } while ($pageToken);
  }
  </code></pre>
  
  <p>And i have 2 files in this folder, one is a picture and the other is folder but the $children var doesn't contain any item :</p>
  
  <pre><code>ChildList Object
  (
      [nextPageToken] =&gt; 
      [kind] =&gt; drive#childList
      [__itemsType:protected] =&gt; ChildReference
      [__itemsDataType:protected] =&gt; array
      [items] =&gt; Array
          (
          )
  
      [nextLink] =&gt; 
      [etag] =&gt; "WtRjAPZWbDA7_fkFjc5ojsEvE7I/lmSsH-kN3I4LpwShGKUKAM7cxbI"
      [selfLink] =&gt; https://www.googleapis.com/drive/v2/files/0B--Zn-zouTFrRURaNWp5VDN5LTA/children
  )
  </code></pre>
  
  <p>I also checked the folderId and is the good one, so not problem there.</p>
  
  <p>My folder :
  <img src="https://i.stack.imgur.com/Y5IYX.png" alt="Folder"></p>
  
  <p>And i don't have any error message</p>