Programming Flex 3

Component Life Cycle

The life cycle that the component framework provides is an important aspect of the Flex framework. By understanding the component life cycle, you will be able to build better components more quickly.

Note

Most of the Flex framework—and the built-in component in particular—is based on the same component life cycle discussed in this chapter. As such, not only is it helpful to learn the component life cycle for building custom components, but it is also helpful for understanding the Flex framework as a whole for building applications.

The component life cycle comprises three phases: initialization, update, and destruction. The initialization phase consists of three main steps: construction, attachment, and initialization (the latter is not to be confused with the initialization phase of which it is a part). The initialization step is composed of its own steps. For instance, during the initialization step, the component dispatches the preinitialize event, calls the createChildren() method, dispatches the initialize event, goes through a full invalidation and validation, and finally dispatches the creationComplete event. At this point, the component has completed the initialization step. Figure 19-2 outlines the initialization phase and its steps.

Figure 19-2. Component life cycle during the initialization phase

The update phase comprises everything that occurs between ...