What's so cool about Flex framework is the fact that it's very extensible, which allows me to do almost anything I want with it.

For example, to remove folder/arrow icons from Flex Tree control, which prevents nodes from collapsing and also creates more space for labels, you can add the following in your stylesheet:

defaultLeafIcon: ClassReference(null); 
folderClosedIcon: ClassReference(null);
folderOpenIcon: ClassReference(null);
disclosureClosedIcon: ClassReference(null);
disclosureOpenIcon: ClassReference(null);

Marko

I've been quiet on the blog front for a while.  I was having a rough time scuba diving in the tropics and so on... If you're interested, take a look at some of my holiday pics I uploaded on facebook.

Now back to business.

At Learnosity, I've been working on migrating our core Flex 3 app to Flex 4.  One of the problems I encountered was embedding an external swf file into the main app. I was getting the following error:

#1053 Illegal override of activate in mx.managers.SystemManagerProxy

It turned out that my Flex 4 app didn't like the external swf because it was compiled with SDK 3.0.  Sounds obvious, but it took me half a day to figure it out :)  I compiled my external swf with SDK 4.0 and everything worked beautifully.

So the lesson learnt is that if your app has other project dependencies, make sure they are all compiled with the same SDK version and you should be sweet.

Marko

I've been using Red5 Flash Streaming Server for a while and the more I use it, the better I like it.  Sure, Adobe Flash Media Server is an excellent commercial product which does the same thing and supports server-side ActionScript.  Red5 doesn't support server-side ActionScript at the moment (this will probably change), but it is an open source Flash server and with a little bit of Java knowledge you can achieve the same result and possibly more.

The following example shows how to display the total number of subscribers that are currently connected to this simple Flex application.  If you open this blog page in multiple browser windows, the number should increase. The reverse will happen when you close browser windows.  This will obviously also depend on the number of other clients connected to the app, but because this is such a "high traffic" blog you probably won't have to worry about that :)  Many thanks go to Learnosity for providing me with Red5 hosting, which makes this demo work.

Dim lights

If you are interested, take a look at Red5 server documentation.