Programming Flex 3

What’s New in Flex 3

If you are familiar with earlier versions of Flex (Flex 1, Flex 1.5, and Flex 2), you may be interested in the relationship between Flex 3 and those earlier versions and what is new in Flex 3. In this section, we’ll look at this subject in more detail.

If you're familiar with Flex 1 or Flex 1.5, but you haven’t used Flex 2, you will find that Flex 3 is dramatically different from the version or versions of Flex you have used. Although Flex 3 continues to utilize MXML and ActionScript (both supported in Flex 1 and 1.5), it is vastly different from Flex 1 and Flex 1.5 in other respects. Flex 3 allows you to compile and deploy independent .swf files without any sort of expensive server-side services as was required by Flex 1 and 1.5. Flex 3 requires Flash Player 9, which allows for (and requires) the use of ActionScript 3. This latest ActionScript version introduces significant changes to the Flash Player API that enable a much improved way to add and remove display objects (including components) to the view.

If you’ve used Flex 2, but you’re new to Flex 3, you may be interested in knowing what is new in Flex 3 that wasn’t available in Flex 2. Some of the most significant changes/additions to Flex 3 are as follows:

Runtime localization/internationalization

Although Flex 2 had built-in localization features, they were compile-time only, and they didn’t allow for runtime switching of locales. In Flex 3, the locale can be changed at runtime, and the resource bundles can even be downloaded on demand.

Flex framework caching

Flex 3 allows you to use the new Flash Player caching feature to cache the Flex framework, reducing the file size for Flex .swf files.

Support for Adobe AIR

Adobe AIR is a runtime environment that allows Flex developers to build applications for the desktop. Flex 3 has native support for building AIR applications.

You can learn about these new features and more throughout the book.