[FLEX-28967] PopUpManagerImpl - centerPopUp method - TypeError: Error #1009: Cannot access a property or method of a null object reference

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Adobe Flex SDK Previous
• Fix Version/s: Apache Flex Next
• Component/s: PopUp Manager
• Labels: EasyFix
• Environment: Affected OS(s): All OS Platforms; Affected OS(s): All OS Platforms; Browser: Internet Explorer 8.x; Language Found: English
• Assignee: Carlos Rovira
• Reporter: Adobe JIRA
• Created: 24/Nov/11 06:14
• Updated: 24/Mar/13 12:34
• Resolved: 24/Mar/13 12:25

Description

Steps to reproduce:

<?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" minWidth="955" minHeight="600">

<fx:Script>
<![CDATA[
import mx.managers.PopUpManager;
protected function button1_clickHandler(event:MouseEvent):void

{ PopUpManager.centerPopUp(w); }

]]>
</fx:Script>

<s:Button click="button1_clickHandler(event)"/>

<s:TitleWindow id="w" bottom="10"/>

</s:Application>

1. using PopUpManager

Error in the code:
public function centerPopUp(popUp:IFlexDisplayObject):void
{
if (popUp is IInvalidating)
IInvalidating(popUp).validateNow();

const o:PopUpData = findPopupInfoByOwner(popUp);

// If we don't find the pop owner or if the owner's parent is not specified or is not on the
// stage, then center based on the popUp's current parent.
var popUpParent:DisplayObject = (o && o.parent && o.parent.stage) ? o.parent : popUp.parent;
if (popUpParent)
{
var systemManager:ISystemManager = o.systemManager;
.
.
.
.

If const "o" is null, popUpParent is set to popUp.parent as stated by condition above.
However in next step you assume that const "o" exists because you're asking for o.systemManager, but o is null.
Therefore: TypeError: Error #1009: Cannot access a property or method of a null object reference

Fix:

public function centerPopUp(popUp:IFlexDisplayObject):void
{
if (popUp is IInvalidating)
IInvalidating(popUp).validateNow();

const o:PopUpData = findPopupInfoByOwner(popUp);

var popUpParent:DisplayObject = (o && o.parent && o.parent.stage) ? o.parent : popUp.parent;
if (popUpParent)
{
var systemManager:ISystemManager;
if (o != null)

{ systemManager = o.systemManager; }

else if (popUpParent.hasOwnProperty("systemManager"))

{ systemManager = popUpParent["systemManager"]; }

else if (popUpParent is ISystemManager)

{ systemManager = popUpParent as ISystemManager; }

if (!systemManager)
return; // or throw exception maybe ?
.
.
.
.