[FLEX-28931] StyleProtoChain throws "Cannot access a property or method of a null object reference" in initProtoChainForUIComponentStyleName()

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: Adobe Flex SDK 4.1 (Release)
• Component/s: Styles
• Environment: Affected OS(s): All OS Platforms; Language Found: English
• Assignee: Unassigned
• Reporter: Adobe JIRA
• Created: 02/Nov/11 10:05
• Updated: 02/Nov/11 10:05

Description

Steps to reproduce:

1. Run the attached Flex4Test.mxml application.

The Flex4Test application loads a rutime style sheet (flex4TestStyle.swf) upon initialization and loads Flex4TestScreen.swf using a ModuleLoader upon creationComplete. It always contains a reference to Flex4TestUtil which has a declaration of Flex4TestScreen.

Actual Results:

The following exception is thrown:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at mx.styles::StyleProtoChain$/initProtoChainForUIComponentStyleName()
at mx.styles::StyleProtoChain$/initProtoChain()
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::initProtoChain()
at mx.core::UIComponent/regenerateStyleCache()
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::addingChild()
at mx.core::UIComponent/addChild()
at mx.controls::ComboBase/createChildren()
at mx.core::UIComponent/initialize()
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()
at mx.core::Container/http://www.adobe.com/2006/flex/mx/internal::childAdded()
at mx.core::Container/addChildAt()
at mx.core::Container/addChild()
at mx.core::Container/createComponentFromDescriptor()
at mx.core::Container/createComponentsFromDescriptors()
at mx.core::Container/createChildren()
at mx.core::UIComponent/initialize()
at mx.core::Container/initialize()
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()
at mx.core::Container/http://www.adobe.com/2006/flex/mx/internal::childAdded()
at mx.core::Container/addChildAt()
at mx.core::Container/addChild()
at mx.core::Container/createComponentFromDescriptor()
at mx.core::Container/createComponentsFromDescriptors()
at mx.core::Container/createChildren()
at mx.core::UIComponent/initialize()
at mx.core::Container/initialize()
at Flex4TestKeyValueScreen/initialize()
at mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::childAdded()
at mx.core::Container/http://www.adobe.com/2006/flex/mx/internal::childAdded()
at mx.core::Container/addChildAt()
at mx.core::Container/addChild()

Expected Results:

The Flex4TestScreen module should load and display a comobobox.

Workaround (if any):

Changing the declaration in the Flex4TestUtil class as follows seems to fix the issue:

Old:

public var flex4TestScreen:Flex4TestScreen = null;

New:

public var flex4TestScreen:Module = null;

The issue with the StyleProtoChain occurs if you use the actual class name of the module instead of the more generic Module declaration.