Important topics about Flex

Basic information to be known by a Flex Developer for interviews

Component's creation life cycle

Components are instantiated, added or linked to a parent, and then sized and laid out inside their container. 

After all components are created and drawn, the Application object dispatches an applicationComplete event. 

* This is the last event dispatched during an application startup.

Single View/ Multiple View

Containers with a single view, such as Box, Form, and Grid containers, create all of their descendants during the container's instantiation because these containers display all of their descendants immediately.

Containers with multiple views, called navigator containers, only create and display the descendants that are visible at any given time. These containers are the ViewStack, Accordion, and TabNavigator containers.

Deferred creation

You could increase the startup time and decrease performance of your applications if you create too many objects or put too many objects into a single view. To improve startup time, minimize the number of objects that are created when the application is first loaded. If a user-interface component is not initially visible at startup, avoid creating that component until you need it. This is called deferred creation. Containers that have multiple views, such as an Accordion container, provide built-in support for this behavior. 

You can use ActionScript to customize the creation order of multiple-view containers or defer the creation of other containers and controls.

After you improve the actual startup time of your application as much as possible, you can improve perceived startup time by ordering the creation of containers in the initial view. The default behavior of Flex is to create all containers and their children in the initial view, and then display everything at one time. The user will not be able to interact with the application or see meaningful data until all the containers and their children are created. In some cases, you can improve the user's initial experience by displaying the components in one container before creating the components in the next container. This process is called ordered creation.






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