ActionScript 2.0 Components Language Reference 
ActionScript 2.0 Components Language Reference |
|
|
|
| DateField component > DateField.scroll | |||
|
|||
|
|||
|
|||
Flash Player 6 (6.0.79.0).
Flash MX Professional 2004.
Usage 1:
var listenerObject:Object= new Object();listenerObject.scroll = function(eventObject:Object) {// ...};dateFieldInstance.addEventListener("scroll",listenerObject);
Usage 2:
on (scroll) {
// ...
}
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 (dateFieldInstance) 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.
The second 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 my_df, sends "_level0.my_df" to the Output panel:
on (scroll) {
trace(this);
}
The following example, written on a frame of the timeline, sends a message to the Output panel when a user clicks a month button on a DateField instance called my_df. The first line of code creates a listener object called dfListener. 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. The target property of an event object is the component that generated the event--in this example, my_df The last line calls EventDispatcher.addEventListener() from my_df and passes it the scroll event and the dfListener listener object as parameters.
// Create listener object.
var dfListener:Object = new Object();
dfListener.scroll = function(evt_obj:Object) {
trace(evt_obj.detail);
};
// Add listener object to DateField.
my_df.addEventListener("scroll", dfListener);
|
|||
|
|||
|
|||
|
|
|
|