Flex: How can I pop up a component in the center of the user's viewable area?

Let's assume I have an application whose dimensions are larger than the user's screen resolution. Typically, when adding a popup I would call popupManager.addPopup() followed by popupManager.centerPopup(), but this could cause the popup to be added outside of the user's visible area on screen.

Is there a way to add a popup in the middle of the user's current viewable area instead?

EDIT: Here's a quick example:

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
               xmlns:s="library://ns.adobe.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx" 
               width="3000" height="2000" 
               creationComplete="creationCompleteHandler(event)">

  <fx:Script>
    <![CDATA[

      import mx.managers.PopUpManager;          
      import spark.components.TitleWindow;

      public var myWindow:TitleWindow = new TitleWindow;

      protected function creationCompleteHandler(event:FlexEvent):void
      {
        myWindow.title = "My Title Window";
        PopUpManager.addPopUp(myWindow, DisplayObject(FlexGlobals.topLevelApplication), false);
        PopUpManager.centerPopUp(myWindow);
      }

    ]]>
  </fx:Script>

  <s:BorderContainer width="3000" height="2000" backgroundColor="0x000000" />
</s:Application>

Example 1:

+==========================+---------------------+
|      Viewable Area       |                     |
|                          |                     |
|     +-------------+      |                     |
|     |  I want the |      |                     |
|     |   popup to  |      |                     |
|     |   go here.  |      |                     |
|     +-------------+      |                     |
|                          |                     |
|                          |                     |
+==========================+                     |
|                                                |
|                Rest of Application             |
|                                                |
|                                                |
|                                                |
|                                                |
+------------------------------------------------+

Example 2:

+------------------------------------------------+
|                                                |
|                Rest of Application             |
|                                                |
|                                                |
|                +===========================+   |
|                |       Viewable Area       |   |
|                |         开发者_Go百科                  |   |
|                |      +-------------+      |   |
|                |      |  I want the |      |   |
|                |      |   popup to  |      |   |
|                |      |   go here.  |      |   |
|                |      +-------------+      |   |
|                |                           |   |
|                |                           |   |
|                +===========================+   |
|                                                |
+------------------------------------------------+

---

centerPopUp() uses the parent object that is passed to addPopUp() or createPopUp() as reference for centering the pop-up. If parent is the application, then it should already be centered based on the width and height of the application - which is what the "viewable area" is from Flex's point of view.

So try passing the application object as the parent argument to addPopUp() or createPopUp()

---

You can calculate it by hand using the stageWidth and stageHeight properties of the stage property:

dlg.x = (this.stage.stageWidth / 2) - (dlg.width / 2);
dlg.y = (this.stage.stageHeight / 2) - (dlg.height / 2);

There may be a more "correct" way to get the dimensions of the viewable area, but I've found that this gets the job done.

Hope that helps.

EDIT: Fixed my mis-information :)