| |
| |
| |
| |
Flash Player 6.0.79.
Flash MX 2004.
Usage 1:
on(click){
...
}
Usage 2:
listenerObject= new Object();listenerObject.change = function(eventObject){...}stepperInstance.addEventListener("change",listenerObject)
Event; broadcast to all registered listeners when the value of the stepper is changed.
The first usage example uses an on() handler and must be attached directly to a NumericStepper component 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 stepper myStepper, sends "_level0.myStepper" to the Output panel:
on(click){
trace(this);
}
The second usage example uses a dispatcher/listener event model. A component instance (stepperInstance) dispatches an event (in this case, change) and the event is handled by a function attached to 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 a set of properties that contains information about the event. You can use these properties to write code that handles the event. Finally, you call the UIEventDispatcher.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 about event objects, see Event Objects.
This example, written on a frame of the Timeline, sends a message to the Output panel when a stepper called myNumericStepper is changed. The first line of code creates a listener object called form. The second line defines a function for the change event on the listener object. Inside the function is a trace action 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 myNumericStepper. The NumericStepper.value property is accessed from the event object's target property. The last line calls the UIEventDispatcher.addEventListener() method from myNumericStepper and passes it the change event and the form listener object as parameters, as in the following:
form = new Object();
form.change = function(eventObj){
// eventObj.target is the component which generated the change event,
// i.e., the Numeric Stepper.
trace("Value changed to " + eventObj.target.value);
}
myNumericStepper.addEventListener("change", form);
| |
| |
| |
| |