How to connect Flex Builder debug session to standalone SWF

I ran into a scenario where I had a swf loading inside a .NET shell and needed to leverage the Flex Builder debugger. The issue I was trying to debug was related to this particular deployment scenario so running the Flex app on it’s own in Builder was not an option.

Here’s the trick. In Builder select “Debug …” and create a new entry under “Flex Application”. Nuke the default values under “URL or path to launch” and enter a bogus URL like “http://localhost/foo.swf”. Now click “Debug” at the bottom right of the dialog box.


A browser window will open and you’ll get a 404. That’s fine. Switch back to to Builder and take a look at the Debugger perspective. You’ll see a debug session has kicked off but no swf has been loaded. (which makes sense since we provided a bogus entry). Now launch your standalone swf, or in my case the windows executable that contains my swf. Remember, you still need to run the debug version of your compiled swf in order for this to work!

Once your swf is loaded take a look at the debugger. You should see it has linked the debug session! Now you can step through or trace till your heart’s content. Not the most elegant solution but hey, it works.

Possibly related posts: (automatically generated)

~ by Stacy Young on January 30, 2007.

Posted in Flex, Flex Builder, Flex SDK

9 Responses to “How to connect Flex Builder debug session to standalone SWF”

  1. Thanks! this problem was driving me crazy. now i can sleep at night.

    andy said this on November 2, 2007 at 8:43 pm

  2. Really cool stuff… to get going…

    Arun said this on December 20, 2007 at 12:21 am

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  5. Thanx!!

    IOU one for this….

    Amit said this on October 16, 2008 at 7:41 am

  6. Nice. Great tip!

    Claire said this on March 11, 2009 at 1:15 pm

  7. Thanks very helpful, no more alert boxes.. yay! haha

    Fedlarm said this on May 15, 2009 at 2:44 am

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    Year One Online said this on June 20, 2009 at 2:45 pm

  9. Just link the “foo.swf” to the “*.exe or .app” binary and Flex will launch the application for you.

    Anthony said this on July 14, 2009 at 11:37 pm

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