Question

I have a main application calling several ViewStack states, each with popup windows. If I don’t open any popup windows, I can move between states fine. If I open a popup window then try to change the state using currentState=... I get the error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at spark.components::Scroller/focusInHandler()[E:\dev\4.y\frameworks\projects\spark\src\spark\components\Scroller.as:2139]
at flash.display::Stage/set focus()
at mx.core::UIComponent/setFocus() [E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:9905]
...

I see others having the same problem, for example here:

http://forums.adobe.com/thread/1031531

http://forums.adobe.com/message/2767130

http://forums.adobe.com/message/3448443

http://forums.adobe.com/thread/655749?tstart=-1

http://forums.adobe.com/thread/801149

http://flex4examples.wordpress.com/2011/05/05/skinnabletextbase-focusmanager-runtime-error-popup/

http://bugs.adobe.com/jira/browse/SDK-32036?page=com.atlassian.jira.plugin.system.issuetabpanels%3Aall-tabpanel

But I haven’t figured out how to implement the recommended solution. It sounds like I should just include:

import mx.managers.PopUpManager; PopUpManager;

inside my main application and it should work, but it doesn’t work for me.

My application has each view state in a different file, each defined using <views:View>. Also, all of the popups are separate files defined as <s:TitleWindow>. Each file includes this line:

import mx.managers.PopUpManager;

I wonder if this means each file is using a different popup manager(?), when it’s a singleton and only one should be used for the whole app (how to set that up?).

The code I use to call a popup is:

var _popupName:MyTitleWindowFileName = MyTitleWindowFileName(
    PopUpManager.createPopUp(this, MyTitleWindowFileName, true));   
_popupName.addEventListener(MyAppController.CLOSE_POPUP,onClosePopUp); 
PopUpManager.centerPopUp(_popupName); // call popup 

Note that when the main application (the one defined as <s:Application>) runs, the ViewStack states have not been loaded yet (since they get loaded when they are used the first time). Not sure if that has any cause/effect here.

I’ve tried to follow Adobe’s example code in the “Passing data to and from a Spark pop-up window” section here:

http://help.adobe.com/en_US/flex/using/WS6c678f7b363d5da52e8f1ca1124a0430dcf-8000.html#WS6c678f7b363d5da52e8f1ca1124a0430dcf-7ffe

Any ideas much appreciated.

Answer 1

It appears this is the situation I’m experiencing:

Adobe Air: scroller throws error when changes focus between different applications

It’s an Adobe bug. Solution from Adobe is:

This bug is easily fixed by changing Scroller to do a null pointer check on focusManager before using it.

which is what the first link above attempts to do.

Another link: http://forums.adobe.com/message/3812805