Flex Development - Difference Between Flex 4 And Flex 3

By Author: aaric sage
Total Articles: 9
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The success or failure of a software development platform depends to a large extent on the unique features it offers. Flex is a wonderful platform evolving to greater heights each time a new version is created. Flex 3 and Flex 4 both are extensively used for Flex development and the former has much better features as compared to the latter. Here is a comparison between both the flex development versions.

The release of Flex 4 was a significant transformation from Flex 3 so far as inclusion of skinning architecture and new components are considered. Though Flex 4 has extravagant features the good thing is that it is still backward compatible. Hence a Flex developer who has worked on Flex 3 will find it relatively easy to embed the features of Flex 3 into Flex 4.

A Flex developer can see a wider difference between the themes of both the versions. MX components as seen in Flex 3 are enriched and called Spark in the latest version. Spark makes the application look and feel different. However if a Flex developer wants they can still use the Halo theme by compiling it using the control panel.

Though Spark relates ...
... to the latest version of Flex for Flex development it supports only limited number of styles. To get more details on which styles are supported a Flex developer should refer ASDoc. Styles which do not have any theme dedicated should be considered to be common with both the themes. Wireframe skin of flex 4 can also be used for fast mock-ups but it should be remembered that it does not support style changes.

Another change that is evident in Flex 4 is the default preloader, it has changed to the light weight mx.preloaders.SparkDownloadProgressBar which aims to make the start time shorter. Adding preloader="mx.preloaders.DownloadProgressBar" in the application tag can give Flex developer access to the preloader as in Flex 3. It would be wise for a developer to develop an application in Flex 4 then to transform it from Flex 3 to Flex 4 migrating each component.

The location of automation library in Flex 4 is {sdk}/frameworks/libs/automation. For Flex development using Flex 4 a developer should ensure that the location in the given version is not {sdk}/frameworks/libs. Design in Mind theme of Flex 4 aims to make the application development flow smoother between the developers and designers. Unlike Flex 3 the theme here separates designing from the rest of the part of the application development.

For components, utils, effects, primitives, filters, skins, core classes and layouts Flex 4 SDK to facilitate Flex development introduces spark.* packages whereas in Flex 3 it is mx.* packages. Class names of many new effects and components in Flex 4 are similar to those in Flex 3 and to avoid name confusion Flex 4 SDK uses 4 different namespaces MXML 2009, Mx, Spark and MXML 2006.

When a feature based comparison is made between the two it is quite clear that Flex 4 is much better as compared to Flex 3. Still most of the Flex development companies use Flex 3 because they are unable to switch between the two. Also there are some companies which work in both the versions.

A Flex development company iFlexweb can develop Flex based applications using either Flex 3 or Flex 4. What we use depends completely on our clients requirements.