The example below shows the working of the addEventListener
method . As
the name suggests, the method adds events in flex components. Here in the example
only mouse event is added in the components, so whenever a mouse click
occurs on the components in which the events are added, an alert pop up window
comes with some messages coded on it. Event listeners are the methods or
functions in which events are added on the flex components or it can be
said as event listeners handles the event that's why they are also
called event handlers. Here in the example we have two event
listener Handler and Handler1 respectively.
With addEventListener method events can be added onto the components indirectly inside the scripting tags, through the components id attribute or directly by defining in the mxml tag through click and initialize attributes or properties of the flex components.
Recommend the tutorial