ActionScript 3.0 :: References And Event Listeners?
May 17, 2010
Lately I've been twitching in the back of my head wondering just how many references to objects that I'm making, and whether or not they are getting GC'd or not.My question in this sense refers to event listeners and whether or not they are removed in certain cases where you get rid of an object. Two examples:
First, and I think this one is an easy one... when you create an object that adds an event listener to itself INSIDE it's own methods (e.g. this.addEventListener(e:Event, function)), when you REMOVE that object (this), do it's event listeners disappear too? I can only say yes, because they are referencing THAT object and are INSIDE that object.
So I think that question answers itself (but I'd love to know if the truth says otherwise).
But secondly, if you add an event listener to an object from a sibling or parent object, and then remove the object, does that event listener stick around, therefore maintaining a reference to that object and keeping it in memory? And is that the concept that people keep referring to of 'weak' event listeners? E.g. someChildObject.addEventListener(e:Event, function)Also, are event listeners by default strong or weak?
And I am assuming that 'yes', it DOES keep the reference. Which, if you are a n00b programmer like me, you probably are all like, 'aww sh*t damn, how am I supposed to make sure that my objects are getting thrown in the garbage collector's mouth of goodness every once in a while?
Before this application runs, I have to do some basic intialising - load up some stuff, build the display list, check I've got the right xml, wire a few objects together. I'm used to doing all of this stuff in the constructor of Main() - my main application class, but it gets a little unwieldy. Would there be any mileage in offloading this into a command class? Is that common practice? I was thinking that way all that Main() would have to do is just listen for events and manipulate methods of the other main classes. The only thing that concerns me is that Main needs references to the main classes and to add event listeners etc. This could be tricky if it's all set up in a command...
I understand how weak references work, but I am bit confused regarding it's use in actionscript event listeners. Consider the example below:
public class Rectangle extends MovieClip { public function Rectangle() { var screen:Shape=new Shape();
[code]...
If the Rectangle object has no other references, then it is a candidate for garbage collection, but since there is an event listener within the object, the event dispatcher holds a reference to the object, even though there are no other references to the object(other than the one held by the event listener). Hence it is prevented from being garbage collected. Is this the reason why weak event listeners are prescribed? Is the flash player so naive that, it cannot figure out that the event listener is defined within the same object?
The problem is I get Error: Error #2094: Event dispatch recursion overflow. Why does removechild keep getting called if this.parent does not exist? Why doesn't removing event listeners work?
Can event listeners only be added to the class which dispatched the event? I ask because I want to have the logic for the listener on the main class, and the action is dispatched on click from a thumb which is instantiated in a scroller class. Kinda like this:
ActionScript Code: pseudo code: class main { main() {
[code]....
This doesn't work. Why can't the main class listen for an event on the thumb class?
So I've gotten into using my own as Classes, and have an interesting question. My main swf calls a php script that gets data from a mysql database which is returned as XML. Part of that data that is retrieved is a filepath to a jpg image. It then takes that filepath and other information, and passes it to my external class, the "news story" class.
All fine and good. Then, the "news story" class uses a loader to load that image along with some text, organize it, and voila, you've got your own very pretty "news story". (I'm extending the MovieClip class here, though I suppose it doesnt matter)
Now, my main swf uses this component to load multiple of these "news stories". The problem is, theres that load time for the image. The main swf is loading them all one at a time, because they are putting each one together on their own.
The key here is that it be dynamic. So, since we don't know how much text is in each "news story", we also therefore don't know it's height. What I'm doing is creating each story in the main swf, pushing it into a "news story" array, adding an event listener to each ones' loader, and when the event listener is triggered, I want it to go to the 'add content' function where it sets the news story's Y value based off the position and height of the previous story that was added (stacking them, obviously). This makes sense, because otherwise it'd add them all on top of each other and it'd be a jumbled mess.
The problem is, the event listener is on the loader object INSIDE the component actionscript. So, how do I figure out which news story to set the Y value for? Because the eventlistener is listening to the loader, not the class. I hope this makes sense AT ALL. Here is the code:
Quote:
while (fancy shmantzy conditions) { /*creates the news story and passes xml data to it (filepath, etc)*/ storyBlock = new StoryBlock(a bunch of parameters); subCBArray.push(storyBlock); //array that stores each news story info
I have made an event listener:text0_mc.addEventListener(MouseEvent.CLICK, showMe);showMe is a function, but I need it to call more than 1 function at once i.e. -ext0_mc.addEventListener(MouseEvent.CLICK, showMe1, showMe2, showMe3, showMe4, showMe5, showMe6, showMe7);Each function contains an if statment as below.
function showMe1(event:MouseEvent):void { if (shuffledArray[1]==orderArray[1]){
I found this code for a contact form at[url]...and it dynamically creates input fields and buttons. I didn't like the dynamically drawn submit and reset buttons, so I added my own MCs(my 'buttons') to the stage.I tried modifying the code and took out the dynamically drawn buttons..However, I cant figure out how to add Event Listeners to the buttons which exist on the stage--Im getting undefined errors...[code]...
I have a movielcip (A) class in which I have used a Tween class effect on a child movieclip (B) scrollRect. The (B) Movieclip in turn has several movieclips whose have tween class effect being executed on thier child movieclips.the tweens are all unique to each movieclip and the event listeners are taken off once completed.This works all well and good in FLASH IDE..My problem arises when I try to view this in a browser on a Windows XP.[code]
What is happening in most cases it that the animation appears to "stick" but i think what may be happening is the listening or removal of the event listeners. The animations are left incompleted.Is there any rule of thumb when using multiple event listeners?[code]the effect disables and re-enables the buttons when its done.... then the listeners are removed.each one with the exception cretes its own unique tween (obviously this is a custom class built as each clip)
I have an array that returns multidimensional data from an mysql database, when this is collected the createNews function creates the user interface. The problem I am having is the loop is iterating quicker than the UI is being created, is there a way to use event listeners with loops so it only continues after my function has completed its work?
In my Flash project I have a movieclip that has 2 keyframes. Both frames contain 1 movieclip each.
frame 1 - Landing frame 2 - Game
The flow of the application is simple:
User arrives on landing page (frame 1) User clicks "start game" button User is brought to the game page (frame 2) When the game is over, the user can press a "play again" button which brings them back to step 1
Both Landing and Game movieclips are linked to separate classes that define event listeners. The problem is that when I end up back at step 1 after playing the game, the Game event listeners fire twice for their respective event. And if I go through the process a third time, the event listeners fire three times for every event. This keeps happening, so if I loop through the application flow 7 times, the event listeners fire seven times. I don't understand why this is happening because on frame 1, the Game movieclip (and I would assume its related class instance) does not exist - but I'm clearly missing something here.
I've run into this problem in other projects too, and tried fixing it by first checking if the event listeners existed and only defining them if they didn't, but I ended up with unexpected results that didn't really solve the problem.
How do you know when you should remove event listeners? For example, I know that if I have a TimerEvent listener, I can safely remove that event when I have stopped and / or deleted my timer. Or, if I have a display object on the stage, and I remove it, I can safely remove any event listeners associated with the display object.
Im sure this has been asked a million times, so forgive me but I cannot seem to find an answer or my search query is wrong. I am using Tweener for animation.
I have 2 MC's on my stage. I have an event listener for my main MC (MOUSE_OVER, MOUSE_OUT) that triggers Tweener to animate another MC on top of the main clip. The problem is that when it overlaps the listener no longer works, and tried to execute the MOUSE_OUT. I understand why its not working, I just cant find a solution. Here is the code and a simple FLA.
well i wish to know, whats the maximum amount of events which can be called?
previously in as2 i ran into this problem when i kept using roll over and roll out events. and very quickly it reached its limit. so i wish to know what the maximum is, and is there any efficient way of asking flash how many are being called?
function myFunction(argument1:int, argument2:int):void { trace(argument 1 + argument2); }
i can use myFunction(1,2); to get a trace of "3" but if it's a mouse event, or timer event, or anything myMC.addEventListener(MouseEvent.MOUSE_DOWN, myFunction); we can't put arguments in this because it would have been
I've an array of movieclips created via code that have some textfields. Then i have added some listeners to the movieclips.
Here the code:
Code: arrNot[i].addEventListener(MouseEvent.MOUSE_OVER, titoloOver); private function titoloOver(e:MouseEvent){ var nome:String = e.target.name; TweenMax.to(curs,1 ,{y:contMain.getChildByName(nome).y + 23}); }
This code moves a cursor calculating the y coordinate depending the moviclip that is mouse overed. Now the movieclips have some textfields so when i mouseover the movieclips all works ok but when i mouseover the textfield i receive a #1009 error.
I have 8 movieclips on the stage: but1,but2,but3,..,but8.How do I use a for loop to add event listeners to each? I am trying this, but i'm sure its not correct:
I've placed listeners on the var "topic_mc" (below), but I'm not sure how to remove them properly:
Code: private function layoutTopics(modNum:Number, attachTo:MovieClip):void { topicLength = MainMenu.modArr[modNum].topicArr.length; if (Interface._ui != null) {[code]....
doesn't really work - any trace statement I place within the event function will run for infinity. How do I call the objects properly to remove the listeners? Note: I've tried referring to currentTarget instead of target but that doesn't make any difference.
Can you put event listeners on bitmaps? Because the current project that I'm working on requires a lot of separate objects which are currently MovieClips, and because there can be several hundred, it causes the app to lag.
is it necessarily to add and remove event listeners like so:
Code:
addEventListener(MouseEvent.MOUSE_DOWN,mDown); function mDown(e:MouseEvent){ removeEventListener(MouseEvent.MOUSE_DOWN,mDown);
[code]....
assuming rapid input, is it really better to do this rather than just let the mouseDown and MouseUp Listeners run all the time? It seems like it would be strenuous to constantly add and remove listeners like this. But this is how i generally see it done..
some time ago i asked about this, and i believe it was senocular who advised me nothing happens if you attempt to add an already existent event listener.xample: this only fires once per frame
I am fairly new to AS3. vancouverMC.dotsBttn.addEventListener(MouseEvent.M OUSE_OVER, mcIn(vancouverMC)); vancouverMC.dotsBttn.addEventListener(MouseEvent.M OUSE_OUT, mcOut(vancouverMC)); function mcIn(mcName:MovieClip):void{ mcName.gotoAndPlay("in"); mcName.ringMC.gotoAndPlay("on"); } function mcOut(mcName:MovieClip):void{ mcName.gotoAndPlay("out"); mcName.ringMC.gotoAndPlay("off"); } Why this is Not Working?
Two buttons, left and right, move the (full screen) backgrounds. If you click the right arrow, the current background moves left, the new background is added to the right, is also moved left, and the old background is faded out. Think of it as a long stream of backgrounds, being moved back and forth with the previously viewed one being faded out with a tween.
The problem is that the arrows appear too soon, and clicking one breaks the whole thing. Main.as adds the arrows & adds the event listeners which then call the functions. The Main.as functions to move the backgrounds use background.moveLeft(); in the backgrounds class, which is where the fade out tweens happen.
So - how do I turn OFF the buttons (added in Main.as) when the tween (in background.as) has finished? I've tried using something like "getNextRoom.addEventListener(TweenEvent.MOTION_FIN ISH, turnOff);" with turnOff referencing the arrows, but it complains that they don't exist (and in the backgrounds class they don't).
