Actionscript :: Making HTTPRequest And Getting Response (Adobe Flex)

Im trying to make a HTTP Request in Adobe Flex (Actionscript) as follows:

var p:PersonSearchController = new PersonSearchController();
showAlertDialog();
p.search(sc);
alert.cancel();
navigator.pushView(views.PersonSearchResults, +p.getResp());

So basically, before the search we get a "Searching..." AlertDialog box, once the search is complete, the dialog box disappears and the results screen is pushed onto the screen...

Here is the search method:

function search{
var requestSender:URLLoader= new URLLoader();
dispatcher.addEventListener(Event.COMPLETE, completeHandler);

[Code].....

p.getResp() is nothing as the response hasn't came back yet. I want the program to basically block until the HTTPResponse is received so I can process the results. At the moment the Popup appear and disappears quickly, and in the background the search goes off and makes the request... I get the response but only after the results screen has been pushed out. How can I make the popup block until we have a HTTPresponse?