User Guide
DateField component (Flash Professional only) 383
...
}
Usage 2:
listenerObject = new Object();
listenerObject.open = function(eventObject){
...
}
myDF.addEventListener("open", listenerObject)
Description
Event; broadcast to all registered listeners when a DateChooser subcomponent opens after a user
clicks on the icon.
The first usage example uses an
on() handler and must be attached directly to a DateField
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 field
myDF, sends
“_level0.myDF” to the Output panel:
on(open){
trace(this);
}
The second usage example uses a dispatcher/listener event model. A component instance (myDF)
dispatches an event (in this case,
open) 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. 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 415.
Example
This example, written on a frame of the Timeline, sends a message to the Output panel when a
date field called
myDF is opened. The first line of code creates a listener object called form. The
second line defines a function for the
open 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
eventObj, to generate a message. The target property of an event object is the
component that generated the event—in this example,
myDF. The DateField.selectedDate
property is accessed from the event object’s
target property. The last line calls
EventDispatcher.addEventListener() from myDF and passes it the open event and the form
listener object as parameters.
form.open = function(eventObj){
trace("Pop-up opened and date selected is " +
eventObj.target.selectedDate) ;