Very odd null object RTE on FocusManager

Question

Hi all,

I am getting this error, randomly when I start my application (and it's sub applications). As you can see the stack trace is rather useless, although through the debugger I can see the parent of container (second in the stack) is an MXML class that has a repeater that repeats another component.

Therefore I guess the component with the problem is that repeated component, although I am unsure what I can change to stop this from happening. If anyone can give me some insight to the FocusManager or the getFocus() function it would be really handy.

TypeError: Error #1009: Cannot access a property or method of a null object reference.
    at mx.managers::FocusManager/getFocus()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\managers\FocusManager.as:542]
    at mx.core::Container/createOrDestroyScrollbars()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\core\Container.as:4571]
    at mx.core::Container/createScrollbarsIfNeeded()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\core\Container.as:4402]
    at mx.core::Container/createContentPaneAndScrollbarsIfNeeded()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\core\Container.as:4218]
    at mx.core::Container/validateDisplayList()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\core\Container.as:2734]
    at mx.managers::LayoutManager/validateDisplayList()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\managers\LayoutManager.as:622]
    at mx.managers::LayoutManager/doPhasedInstantiation()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\managers\LayoutManager.as:677]
    at Function/http://adobe.com/AS3/2006/builtin::apply()
    at mx.core::UIComponent/callLaterDispatcher2()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\core\UIComponent.as:8733]
    at mx.core::UIComponent/callLaterDispatcher()[C:\autobuild\galaga\frameworks\projects\framework\src\mx\core\UIComponent.as:8673]

Thanks

Rob

Answer 1

It seems that the problem was related to removing a SWF from the stage whilst is was still loading.

http://tech.groups.yahoo.com/group/flexcoders/message/147691

The solution would be to only remove SWFs from the stage once they are fully loaded.