Conveniently, when you refer to a method through an object reference with the dot. In actionscript 2, the import statement is a convenience that allows you to reference a class without having to type its full package name. Heres where we start off with eventdispatcher in our class. Make all you labels instance as a child to one container like sprite or movieclip. Aug 25, 2008 this new article provides java developers with a transition guide to actionscript which forms the foundation of flex. Find answers to dispatch event in document class as3 from the expert community at experts exchange. Load swf via actionscript 3 with this class general. Eventdispatcher, like asbroadcaster broadcasts an event to a set of listeners which then receive.
You can create your own events and dispatch them, by extending the event class. Actionscript 3 add your own events actionscript3 tutorial. Before examining the external actionscript file, there is one additional setting you need to be aware of. Is it possible to listen the event triggered by an. Eventdispatcher is a class which provides a means of dispatching events. Flashplatformreferenceactionscript3flasheventsieventdispatcher. Choose file publish settings and click the flash tab. So your public static function dispatchevent cant take a part in eventdispatcher or ieventdispatcher.
If the dispatcher of the event is a child component, we could do the same in actionscript. In actionscript 2, the import statement is a convenience that allows you to reference a class without having to. Not really necessary here but original eventdispatcher implements it and. Jul 09, 2007 creating custom event handlers in actionscript 3 is pretty much simple. Implement ieventdispatcher not for the static class. In this post im going to show how you can create, dispatch and listen for custom events. This class is implementing singleton design pattern which means that only one instance is.
The real problem appeared around numbers described actionscript objects. Eventdispatcher adobe actionscript 3 as3 api reference. Now lets go back to the event listener function and. If usecapture is false, the listener processes the event only during the target or bubbling phase. For the rest of this chapter, well be using the following event handlers. The eventdispatcher class allows any object on the display list to be an event target and as such, to use the methods of the ieventdispatcher interface. The urlrequestmethod class provides values that specify whether the urlrequest object should use the post method or the get method when sending data to a server. Actionscript custom event tutorial curious minds media. This target, though, is indispensable, as it provides access to the event dispatcher to the event listener, allowing the listener to get the data it needs from the dispatcher. In other situations, perhaps you would like to create a class that has a bunch of static methods on it, and isnt really meant to be instantiated. This article covers the new features related to event handling in actionscript 3. Here is a simple example which loads an image and fires a custom event named onimageload as soon as image is loaded.
In general, the easiest way for a userdefined class to gain event dispatching capabilities is to extend eventdispatcher. Jul 11, 2007 now some other object in a whole can listen for this event, without ever knowing the target object ever existed, well without a passed reference at least. Im not going to get into a big complicated explanation right now, but i will show you a couple of simple examples. The idea of eventdispatcher is that you are listening for events that occur on an object. Static methods and properties will be covered briefly in the next chapter and in detail in the third section. For reference see adobe help event constructor and also the event flow. Flexevent adobe actionscript 3 as3 flex api reference. Obviously in this case its quite pointless to create a custom event, but i am showing you the way you can do it.
This information is contained in what is referred to as an event object. In this tutorial ill explain about the actionscript 3. This target, though, is indispensable, as it provides access to the event dispatcher to the. Dispatch event in document class as3 solutions experts. This new article provides java developers with a transition guide to actionscript which forms the foundation of flex. The eventdispatcher class allows any object on the display list to be an event target and as such, to use the meth. You can create the same static methods as in ieventdispatcher and then create a static instance of ieventdispatcher to handle events but your static class itself cant be. If this is impossible that is, if the class is already extending another class, you can instead implement the ieventdispatcher interface, create an eventdispatcher member. Note, however, that this will only work for events that are bubbling up from children components. Load swf via actionscript 3 with this class here is a class that you can use to load swfs into an object that you can display or do whatever youd like with. Learning how to use events can be a tricky process for a new actionscript developer, but once you get the hang of it, youll be surprised how powerful and versatile extending the event class can be. That is, a new eventdispatcher object, not necessarily any of its subclasses.
Jun 03, 2009 in this script, we are counting the time passed like in understanding as3 timer class, but we want to create a custom event to be triggered every 5 seconds. Video learning guide for flash adobe developer connection. The eventdispatcher class implements the ieventdispatcher interface and is the base class for the displayobject class. The event class is used as the base class for the creation of event objects, which are passed as parameters to event listeners when an event occurs. Checking for custom events is done in the same way that you deal with any other event in as3. This parameter is what is used to accept that event object whenever it gets passed to the event listener function. Creating custom event handlers in actionscript 3 is pretty much simple. You can create the same static methods as in ieventdispatcher and then create a static instance of ieventdispatcher to handle events but your static class itself cant be eventdispatcher but can only look the similar. Event handling in actionscript has changed significantly over the past few releases of flash player.
To do so you can create static constants on the dispatcher or, if you want to be in the cool crowd. When an event such as a mouse click or a keypress occurs, flash player or the air application dispatches an event object into the event flow from the root of the display list. I havent seen an example of where id need static event dispatching. Then in your document class you would handle all events thru this proxy through static reference. The urlrequestmethod class provides values that specify whether the urlrequest object should use the post method or the get method when sending data to a server view the examples. The eventdispatcher class allows any object on the display list to be an event target and as such, to use. How to dispatch a custom event in actionscript 3 nuts. Find answers to actionscript 3 and customizing the eventdispatcher from the expert community at experts exchange. Though actionscript 3 is a strongly typed language, the contents of an array may be of any type and values must be cast back to their original type after retrieval. I have a class name imageloader that is used to load image and the dispatch a complete event when the image is loaded. Thanks grant, the static event dispatcher saved me much time. Now some other object in a whole can listen for this event, without ever knowing the target object ever existed, well without a passed reference at least.
In actionscript 3, you dispatch an event by extending the eventdispatcher class. Aug 25, 2008 event handling in actionscript has changed significantly over the past few releases of flash player. This way you can handle the event in a centralized manner. So that is the basic flow of how events in as3 are handled. The event model provided by actionscript 3 is a rather good and convenient way to facilitate communication between your classes, while maintaining a separation of responsibilities in your classes. In the previous examples we initialized each broadcaster individually. Learn more about creating a custom event listener in as3 from the expert community at experts exchange. In your code, the event target will be some useless object that has no meaning to any other object in your application. To listen for the event in all three phases, call addeventlistener twice, once with usecapture set to true, then again with usecapture set to false. In this script, we are counting the time passed like in understanding as3 timer class, but we want to create a custom event to be triggered every 5 seconds. After this tutorial you should have a clear understanding of how events, event dispatchers and event listeners work.
May 29, 2008 actionscript custom event tutorial posted on may 29, 2008 by curiousmindsmedia learning how to use events can be a tricky process for a new actionscript developer, but once you get the hang of it, youll be surprised how powerful and versatile extending the event class can be. Creating a custom event listener in as3 experts exchange. This is going to be a very simple example of how to dispatch an event. The properties of the event class carry basic information about an event, such as the event s type or whether the event s default behavior can be canceled.
You have mouse down and mouse up events for actionscript 3. Your menupanel instance should be listening to the changed event from dispatch instance dispatcher. Nov 29, 2010 every time a dispatched event triggers an event listener function to run, information gets passed to that event listener function. As3 using a static class to manage events between scopes blog. The properties of the event class carry basic information about an event, such as the events type or whether. The event target serves as the focal point for how events flow through the display list hierarchy. This class is implementing singleton design pattern which means that only one instance is created always for this class. The eventdispatcher class is the base class for all classes that dispatch events. Event listening with mxml and an actionscript event listener. Ondemandeventdispatcher adobe actionscript 3 as3 flex. The key and mouse classes contain a lot of event handlers which are, surprisingly enough, related to the keyboard and mouse respectively. Because actionscript 3 does not allow multiple inheritance, how do you reconcile this. Eventdispatcher, like asbroadcaster broadcasts an event to a set of listeners which then receive that event and call the function associated with it.
We could do this here and initialize each instance as a broadcaster in the class constructor. Building a static eventdispatcher in as3 gskinner blog. Memory leaks in adobe air mobile as3 project namekdev. After youve recovered from that bombshell of an introduction sentence, lets get more in depth. Actionscript 3, events, event flow, event phasen, dispatcher. Garbage collector which sucks, event dispatcher, event bus. I mean to say the sprite which is parent to all your labels instance will listen for the events dispatched by any of the instance. If data is to be pulled, though, generally the event object has very little information contained within just the necessities.
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