The Scenario
In this particular case I had a tree component displaying a hierarchical view of the pages of a web site. Upon making some certain changes, like dragging and dropping pages to reorder them I felt the need to change the order server-side and reload the data, rather than changing the order inside the dataProvider. I just like it that way better.

The Problem
So before I reloaded the data I saved the tree’s open items in a variable called openTreeItems and when I received the new data I tried to reset it by using tree.openItems = openTreeItems.
Nothing happened.

The Research
So I started doing some research and quickly discovered that to make this work the component uses the uid property and on updating the data for the dataProvider Flex reassigns new uid’s to the items in the collection. So, in short, Flex doesn’t recognize the items as the same items after the reload, because of the new uid values.

I encountered this article in the Flex 3 Help pages and started experimenting with creating custom classes that implemented the IUID interface and soon discovered that this was way to complicated for the (actually) quite simple problem I had. The pages in my database had unique ID’s! Why the h*ll couldn’t I use these values as the uid values instead of the built-in values?

The Solution
I suddenly had an idea: what if I simply add the uid property to my data serverside by using the id value I already had? This could be done in many ways but I chose to alter my SQL query like so:
“SELECT pages.id, pages.id uid, … FROM pages…”. This way the value would be passed on into Flex the same way as all the other values.

And, voilà, it worked!
After this tiny alteration of my SQL query Flex recognized my items as the ones saved in the openTreeItems variable and when using tree.invalidateList() before the update and tree.validateNow() after the update there isn’t even a flicker upon updating the data. Sweetness!

Hope this helps anyone that has had the same problem.

Well, it is actually very easy. If you look at the trace script Google Analytics gives you to add to your HTML code you can find a call to a method that actually records the event. This method is simple to call using JavaScript.

I have solved it like this in my latest Flex App (which is a public site). NOTE: This is for the new trace code version.

1. Paste the Google Analytics trace code as usual just before the </BODY> tag.
Check your Google Analytics account for the correct code.

2. See to it that your embedded flash works with ExternalInterface.
This can be a bit tricky, but in my experience the things that do the trick are to change allowScriptAccess to always and inside the Flex App call a custom JavaScript function on creationComplete like so: ExternalInterface.call(’initFlash’). In my html this initFlash function creates a variable reference to the embedded flash. This sort of “creates the connection” between them. I’m not sure why this is so, but for me it works, so I’m happy with that. If there is a need I would be glad to create a more thorough tutorial on the use of ExternalInterface. Just let me know.

3. Create a custom JavaScript that passes the URL you want to register to the Google Analytics script.
This is not necessary, but I have found it easier to work with, as you don’t need to edit you call from inside of Flex if something changes in the Google code or such.

4. Call your custom javascript from within Flex.
I created a static class for this. (I love static classes). I named it Analytics.as and placed it in the root source folder in the Flex App. It looks like this. All it does really is call the JavaScript using ExternalInterface, but putting it within a static class lets you call it from anywhere in your application without having to pass on references to this or that object or function.

And anywhere in your app write:

(NOTE: You have to start your path with a slash).

There you go. It now should track the URL:s you want and give you nice statistics.

However, writing the class I realized I wouldn’t be able to pass on the optional parameters. If I would use:

…I wouldn’t be able to send the args argument to the NetConnection.call method, because actionscript would send a “bunched up” array with all the arguments as ONE parameter to the call method, as opposed to a series of parameters, which was what I wanted.

The solution to this is using the Function.apply() method. What I did was to create an empty array and add a series of arguments I wanted to pass on to a function, create a reference to the function and then use the apply method. This is what my finished static method looks like: