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This article will explain in detail about the changes in Flex4. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

1. Integrated AdobeCatalyst

One of the main features of Flex4 is that it provides support for AdobeCatalyst (a new Adobe design tool for creating rich Internet applications without writing code). Catalyst has changed the way developers and designers collaborate because it is well aware of the significant differences in the way application developers and designers work. In this way, both developers and designers can focus on what they are good at, and with Catalyst, both developers and designers can work in the way they are used to. Many of the changes in Flex4 revolve around the integration of Flex and Catalyst. Check out the AdobeCatalyst site for more information.

2.Spark component architecture

Each version of Flex contains a complete component library with common components for building applications, such as data tables, buttons, layout containers, and so on. The underlying component architecture of Flex4 is called Spark, while in Flex3 it is called Halo. In order to support Catalyst,Flex4, the underlying component model is updated to achieve the purpose of loose coupling.

In the new Spark component model, the core logic, skin, and layout are separated so that we can deal with any part of it separately without affecting the others. The Spark component model is built on top of the Halo component model, which means that Spark extends UIComponent, the core base class of Halo, so that we can use Flex4 incrementally and apply Flex3 components to Flex4 applications.

In addition, Flex4 also enhances the effect. Effects can now be applied to any object and type, which increases its flexibility. The effect of Flex4 is achieved by the new "spark.effects" package. Like the new component library, the effect of Flex4 has been reimplemented, but no changes have been made to the effect of Flex3 in order to maintain backward compatibility. Check out ChetHaase's articles about Flex4 effects or his blog to learn more about GumboEffect.

Please read the white paper to learn more about the Spark architecture.

3.MXML2009

MXML is based on XML and is built on ActionScript3, the programming language used by FlashPlayer. MXML is used to lay out the view area of the user interface and supporting tools, such as IDE, now Catalyst. MXML2009 includes a large number of updates to decouple different behaviors (core, skin, and layout), as well as a new component library. Now that the components of Flex4 are implemented in its own package (spark.components) without making any changes to the components of Flex3, MXML2009 provides a new namespace to provide support.

The following application declaration example shows how to use this namespace and how to define namespaces for Spark and Halo components:

In this way, we can declare the Button of Flex4 with the following code:

The following code declares the Button of Flex3:

Please browse the MXML2009 specification to learn more about its changes.

4. Improvements to ViewStates

Flex2 introduces the concept of states into the Flex framework so that we can manage changes in view components through simple state changes. Flex4 has improved view state (viewstates) to simplify its syntax so that we can use them more easily. The new language attributes includeIn and excludeFrom are examples of simplified syntax, and we can set the values of these two properties of the component in response to state changes (see the code example below).

Please click here to learn more about the changes in ViewStates.

5.FXG support

The core of FlashPlayer is a drawing engine. Adobe introduced FXG in FlashPlayer10 and now Flex. FXG is a declarative graphical format that delivers content between tools, which means that designers can create content in Catalyst or CS4Illustrator, which can then be imported and used by Flex application developers without modifying anything.

Please read the FXG specification for more details.

6. Skin enhancement

The change in the Spark component model lies in the subversive modification of the skin, which now controls all visual parts of the component and encapsulates logic outside the core of the component. In this way, we can modify the visual part of the component independently without affecting the underlying core logic.

7. Updated layout components

People familiar with Flex development may notice that most of the containers in Flex3 are no longer in the Gumbo component library. This is because the layout has been decoupled and now we need to deal with them through the delegtion. Because most Flex3 containers are simply designed to provide different layout styles (such as HBox for horizontal layout, VBox for vertical layout, and so on), they are of little use now.

The following example shows that Flex developers can now define layouts as well. This example leverages the Group class to manage buttons, and Group is a new Spark class that manages the content items in it. The result of the layout is two buttons placed side by side, just like the result of using HBox in Flex3.

RyanStewart from Adobe makes an in-depth analysis of the new layout mechanism.

8.FlashBuilder4

FlashBuilder4 (formerly known as FlexBuilder) is an EclipseIDE for application developers. This new version comes with a number of updates, including conditional debugging breakpoints, more refactoring tools, and support for FlexUnit4. As always, it also includes MXML, ActionScript3, a visual designer, and a Flex performance and memory analyzer (which is available only in the professional version).

In addition, the * * version also provides advanced data management features to simplify the development of data-centric applications. This includes the client's data management feature, which handles CRUD operations and scrolls through large collections.

Click here to learn more about the IDE.

9. Compiler performance

Almost every Flex3 developer has a pain in his heart-poor compiler performance. Based on this, one of the main goals of Gumbo is to improve compiler performance in Flex4. Although the official performance benchmark has not yet been released, PeterDonovan from Adobe has tested it based on some of its own experiments, and the results show that the performance of the new compiler has improved by 25%. He says the only way to improve performance by three to four times is to redesign it. Of course, every developer of an enterprise Flex application hopes to achieve this when Flex4 is officially released at the end of this year.

Please read PeterDonovan's article for more information.

10. New text function

One of the main issues of Flash applications, whether Flex or non-Flex applications, is the ability to process text efficiently. In FlashPlayer10, Adobe introduced a new text engine to support the needs of RIA (multilingual, printing, keyboard shortcuts, etc.). Gumbo introduces a large number of new text classes (RichText, SimpleText, and so on) to provide more robust text support in the Flex framework. In addition, Adobe is working hard on a new TextLayoutFramework to give ActionScript3 developers the ability to take advantage of the FlashPlayer text engine.

This is the end of this article on "what's changed in Flex4". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it out for more people to see.

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