DispatchEvent Confusion ?
Hi all
I’m trying to understand dispatchEvent, so I’m trying to write a little example. I have 3 classes.
- Document Class - to start it off.
- Dispatcher Class - to dispatcher the Event
- Listener Class - to listen for the dispatched event, and produce a trace to confirm.
The code just gives me a TypeError -
TypeError: Error #1009: Cannot access a property or method of a null object reference.
Which I think means I’m trying to reference something that isn’t there yet - How do I ensure the classes are there to be used ?
Any help on this would be really appreciated - I just want a simple working example to understand how DispatchEvent works.
Document.as
package{
import flash.display.MovieClip
import Dispatcher
import Listener
public class Document extends MovieClip{
private var _lis:Listener
private var _dis:Dispatcher
public function Document(){
_lis = new Listener()
_dis = new Dispatcher()
_dis.sendOut()
}
}
}
Dispatcher.as
package{
import flash.events.*
public class Dispatcher extends EventDispatcher{
public static const MESSAGE:String = "update"
public function Dispatcher(){
}
public function sendOut(){
dispatchEvent(new Event(Dispatcher.MESSAGE))
}
}
}
Listener.as
package{
import flash.events.*
import Dispatcher
public class Listener{
private var _dis:Dispatcher
public function Listener(){
_dis.addEventListener(Dispatcher.MESSAGE, myFun)
}
public function myFun():void{
trace("Message received")
}
}
}
