User Guide

428 DateChooser component (Flash Professional only)
Description
Event; broadcast to all registered listeners when a month button is clicked.
The first usage example uses a dispatcher/listener event model. A component instance (
myDC)
dispatches an event (in this case,
scroll) and the event is handled by a function, also called a
handler, on a listener object (
listenerObject) that you create. You define 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 (
eventObject)
to the listener object method. Each event object has properties that contain information about
the event. You can use these properties to write code that handles the event. The scroll event’s
event object has an additional property,
detail, that can have one of the following values:
nextMonth, previousMonth, nextYear, previousYear.
Finally, you call the
EventDispatcher.addEventListener() method on the component
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 “EventDispatcher class” on page 499.
The second usage example uses an
on() handler and must be attached directly to a
DateChooser instance. The keyword
this, used inside an on() handler attached to a
component, refers to the component instance. For example, the following code, attached to
the date chooser
myDC, sends “_level0.myDC” to the Output panel:
on (scroll) {
trace(this);
}
Example
This example, written on a frame of the timeline, sends a message to the Output panel when a
month button is clicked on a DateChooser instance called
my_dc. The first line of code
creates a listener object called
form. The second line defines a function for the scroll event
on the listener object. Inside the function is a
trace() statement that uses the event object
that is automatically passed to the function, in this example
evt_obj, to generate a message.
// Create listener object.
var dcListener:Object = new Object();
dcListener.scroll = function(evt_obj:Object) {
trace(evt_obj.detail);
};
// Add listener object to date chooser.
my_dc.addEventListener("scroll", dcListener);