User Guide

ScrollPane component 683
Event object
In addition to the standard event object properties, there are two additional properties defined for
the
scroll event: a type property whose value is "scroll", and a direction property whose
value can be
"vertical" or "horizontal".
In addition to the standard event object properties, there are two additional properties defined
for the
ProgressBar.progress event: current (the loaded value equals total), and total (the
total value).
Description
Event; broadcast to all registered listeners when a user clicks the scroll bar buttons, scroll box
(thumb), or scroll track. Unlike other events, the
scroll event is broadcast when a user presses
the mouse button on the scroll bar and continues broadcasting until the mouse is released.
The first usage example uses an
on() handler and must be attached directly to a ScrollPane
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 instance
sp, sends
“_level0.sp” to the Output panel:
on(scroll){
trace(this);
}
The second usage example uses a dispatcher/listener event model. A component instance
(
scrollPaneInstance) 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.
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 creates a form listener object with a scroll callback function that’s registered to the
spInstance instance. You must fill spInstance with content.
spInstance.contentPath = "mouse3.jpg";
form = new Object();
form.scroll = function(eventObj){
trace("ScrollPane scrolled");
}
spInstance.addEventListener("scroll", form);
See also
EventDispatcher.addEventListener()