MACROMEDIA FLASH MX 2004-USING COMPONENTS Use Manual page 630

Usage 2:
listenerObject = new Object();
listenerObject.click = function(eventObject){
...
}
radioButtonGroup.addEventListener("click", listenerObject)
Description
Event; broadcast to all registered listeners when the mouse is clicked (pressed and released) over
the radio button or if the radio button is selected by means of the arrow keys. The event is also
broadcast if the Spacebar or arrow keys are pressed when a radio button group has focus, but none
of the radio buttons in the group are selected.
The first usage example uses an
instance. The keyword
component instance. For example, the following code, attached to the radio button
myRadioButton
on(click){
trace(this);
}
The second usage example uses a dispatcher/listener event model. A component instance
(
radioButtonInstance
function, also called a handler, on a listener object (
a method with the same name as the event on the listener object; the method is called when the
event is triggered. When the event is triggered, it automatically passes an event object
( ) to the listener object method. The event object has properties that contain
eventObject
information about the event. You can use these properties to write code that handles the event.
Finally, you call the
instance that broadcasts the event to register the listener with the instance. When the instance
dispatches the event, the listener is called.
For more information, see
Example
This example, written on a frame of the Timeline, sends a message to the Output panel when a
radio button in
radioGroup
The second line defines a function for the
is a statement that uses the event object (
trace()
function to generate a message. The
generated the event. You can access instance properties from the
example, the
RadioButton.selection
EventDispatcher.addEventListener()
the listener object as parameters.
form
form = new Object();
form.click = function(eventObj){
trace("The selected radio instance is " + eventObj.target.selection);
630 Chapter 6: Components Dictionary
handler and must be attached directly to a RadioButton
on()
, used inside an
this
, sends "_level0.myRadioButton" to the Output panel:
) dispatches an event (in this case,
EventDispatcher.addEventListener()
"EventDispatcher class" on page
is clicked. The first line of code creates a listener object called
target
handler attached to a component, refers to the
on()
click
listenerObject
415.
event on the listener object. Inside the function
click
) that is automatically passed to the
eventObj
property of an event object is the component that
property is accessed). The last line calls
from and passes it the
radioGroup
) and the event is handled by a
) that you create. You define
method on the component
property (in this
target
click
.
form
event and