Daniel R.: Could not resolve * to a component implementation.

Often when refactoring code I'll extract ActionScript code out of an MXML file into an ActionScript based superclass to get a cleaner separation between logic and the view. In doing so I sometimes forget to update MXML variable declrations, leading to the confusing error:

Could not resolve <mx:states> to a component implementation.

In this case my MXML class extends another custom class and looks like:

<?xml version="1.0" encoding="utf-8"?>
<example:CustomCanvas xmlns:example="com.example.*" xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:states>
<mx:State name="default"/>
<mx:State name="custom"/>
</mx:states>
</example:CustomCanvas>

The issue is that the "mx" namespace doesn't match the root component's namespace so the MXML compiler gets confused about it being a property versus a child component. The simple fix is to just change the namespace on the property to match the root component's namespace like this:

<?xml version="1.0" encoding="utf-8"?>
<example:CustomCanvas xmlns:example="com.example.*" xmlns:mx="http://www.adobe.com/2006/mxml">
<example:states>
<mx:State name="default"/>
<mx:State name="custom"/>
</example:states>
</example:CustomCanvas>

Comments

Thanks very much for posting this. It really helped me resolve the issue quickly. No thanks to the adobe docs!

Posted by: S2 | March 16, 2007 4:28 PM

hi, thanks this was very helpful. regards, san

Posted by: san | August 17, 2007 8:29 AM

Thanks for the tip ;)

Posted by: Jorge Rodrigues silva | January 17, 2008 12:46 PM

Good post, I ran into this while extending framework components.

-Shailesh

Posted by: Shailesh Mangal | February 5, 2008 7:33 PM

very helpful. thanks!

Posted by: kris | February 26, 2008 1:16 PM

Good catch!

Posted by: joe beuckman | May 15, 2008 1:31 PM

thanks!

Posted by: Marc H. | July 20, 2008 8:17 AM

Thank you. I was working on an application and came to this. Was about to toss the keyboard through the window when I came across this post!

Posted by: diamondtearz | September 24, 2008 2:00 PM

Thanks!

Posted by: Thijs | October 9, 2008 9:16 AM

Thanks very much! I've been caught in this problem for an hour.

Posted by: mizti | October 16, 2008 7:36 AM

Thank you. i meet same issue and now resloved. :)

Posted by: jzuo | December 5, 2008 3:09 AM

Thank you very much, very, very helpful !

Posted by: Thomas B. | December 17, 2008 3:22 PM

Great post Daniel. Save me lot of time.

Posted by: ralph | January 21, 2009 12:29 PM

Thanks a lot for ur post.. Gr8 job mate.. Please mail us any critical issues.

Posted by: Arnab Jyoti Sarkar | January 28, 2009 3:45 AM

thank you very much for this, saved me valuable time.

Posted by: Noah | February 12, 2009 10:46 AM

Thanks for your post. Saved me a BUNCH of time!

Posted by: Brian | February 21, 2009 1:17 PM

Something makes me uneasy about using standard mx components under a custom namespace. But it solved my problem, and for that I'm grateful.

Posted by: Jesse Bethke | February 27, 2009 5:47 PM

Thanks a lot! Once you know what's happening it makes a lot of sense, but that compiler error sure had me scratching my head for a while.

Posted by: Katy | April 10, 2009 9:27 PM

This is a key thing to know, thanks. It would be nice if Adobe docs were more helpful on this and other confusing issues. Most of their errors are abismal.

Posted by: Gerry | April 21, 2009 1:19 PM

thanks. :D

Posted by: Adrian | May 11, 2009 1:58 AM

THANKS!

Posted by: Richard N. Sparrow | May 17, 2009 4:06 PM

Thank you very much for posting this. Solved my problem lickety split.

Posted by: Dan Moore | June 5, 2009 8:11 PM

i had a similar problem but the its because there are 2 files with the same name: myform.mxml and myform.as (which is referenced by myform.xml). in the preview tab it shows the component but when there is this error when running it. solution: rename myform.as to be myformscript.as or something different with the mxml file.

Posted by: xtedx | July 13, 2009 6:42 AM

Good post!

It's kind of obvious when you think about it -- the give away is the lower case on which means it is referring to an attribute of an object rather than the name of a class, so "obviously", the attribute has to be referenced out of the same namespace as its object.

Thanks again

Posted by: Sean Fisher | July 22, 2009 4:44 PM

Your the best !

Posted by: Mark Lord | December 2, 2009 7:34 PM

cheers...

Posted by: Toni | January 6, 2010 9:00 AM

I've been coding in Flex for about 2 years, but this one still stumped me. I suppose it makes sense though. Thanks for posting this; you saved me a lot of time!

Posted by: zourtney | January 27, 2010 11:46 AM

thanks for you help

Posted by: tom | March 31, 2010 5:38 AM

Thanks. You helped me out!

Posted by: Lisa | May 31, 2010 1:23 PM

Thanks.

Posted by: Sanjeev | June 14, 2010 1:23 PM

thanks a lot it solve my problem

Posted by: pradeep | July 20, 2010 7:04 AM

Very Nice

Posted by: velu | August 2, 2010 7:32 AM

thanks