In Part 2 of this series, I showed you how to make external itemRenderers in both MXML and ActionScript. In the examples I've been using, there is a Button which dispatches a custom event—BuyBookEvent—so the application can react to it. This article covers communication with itemRenderers in more detail.

There is a rule I firmly believe must never be violated: you should not get hold of an instance of an itemRenderer and change it (setting public properties) or call its public methods. This, to me, is a big no-no. The itemRenderers are hard to get at for a reason, which I talked about in Part 1: the itemRenderers are recycled. Grabbing one breaks the Flex framework.

With that rule in mind, here are things you can do with an itemRenderer:

• An itemRenderer can dispatch events via its list owner. (You've seen bubbling; this is a better practice, which you'll see below.)
• An itemRenderer can use static class members. This includes Application.application. If you have values stored "globally" on your application object, you can reach them that way.
• An itemRenderer can use public members of the list that owns it. You'll see this below.
• An itemRenderer can use anything in the data record. You might, for example, have an item in a record that's not for direct display, but which influences how an itemRenderer behaves.

This series includes the following articles:

• Part 1: Inline renderers
• Part 2: External renderers
• Part 3: Communication
• Part 4: States and transitions
• Part 5: Efficiency

Requirements

In order to make the most of this article, you need the following software and files:

Flex Builder 3

• Try
• Buy

Prerequisites

To benefit most from this article, it is best if you are familiar with Flex Builder and ActionScript 3.0.

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License

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