I have multiple object doing random movement with random speed. i wanted to repeat the animation.
I tried to use onComplete to restart each object once the animation end, but how could I specifically target it to that object? Currently its overflow
private function lineAnimation (e:DisplayObject):void
{
TweenLite.to (e,randomTime, {x:randomX, onComplete: lineAnimation(e)});
}
When you set a callback for onComplete, you need to just pass the function itself. By setting onComplete: lineAnimation(e), it is executing lineAnimation again over and over. As you need to pass the parameter, you can use an anonymous function for the callback like so:
private function lineAnimation (e:DisplayObject):void
{
TweenLite.to(e, randomTime, {x:randomX, onComplete:function():void {lineAnimation(e)}});
}
Also since you are using TweenLite, you may want to check out TweenMax which has looping built-in so you can do something like so:
TweenMax.to(e, randomTime, {x:randomX, repeat:-1}); // -1 repeats indefinitely
Related
I have the following code:
//Main Entry Point.
start() {
this.init();
this.gameLoop();
}
//Init, runs only once.
init() {
let initalEntity1: Entity = new Entity(10, 10, Gender.female);
let initalEntity2: Entity = new Entity(60, 60, Gender.male);
console.log("There are " + this.Entities.length + " Items in the entities Array")
this.Entities.push(initalEntity1, initalEntity2);
console.log("There are " + this.Entities.length + " Items in the entities Array")
}
gameLoop() {
console.log("Performing a Game Loop");
requestAnimationFrame(this.gameLoop);
//MAIN LOOP THROUGH ENTITIES
for (let i in this.Entities) {
this.Render.drawEntitysToScreen(this.Entities[i].EntityPosition, this.Entities[i].gender);
}
}
It enters into start() fine, and also performs all of the init() functionality. it them proceeds onto gameloop() which it will run once, however the line requestAnimationFrame(this.gameLoop); which is ment to retrigger the function to be called as a Canvas frame is causing the following error:
TypeError: this is undefined
trying to requestAnimationFrame(gameLoop); but it causes the typescript compiler to get upset...
This is due to how this binding works in javascript. The way by which you are passing this.gameLoop to requestAnimationFrame is essentially passing an unbound gameLoop function, and so when it is called, it has lost reference to its this.
There are a number of possible solutions to this problem:
You can bind this.gameLoop to this inside of the class constructor, like so:
constructor() {
this.gameLoop = this.gameLoop.bind(this);
}
You can bind this.gameLoop to this as part of the gameLoop method definition. Rather than defining gameLoop like
gameLoop() {
If you instead use
gameLoop = () => {
it will be automatically bound to this. This is a property of using the fat arrow for function declarations: it automatically performs binding to the this that exists at the function declaration.
You can change how you pass gameLoop to requestAnimationFrame:
requestAnimationFrame(() => this.gameLoop());
This again takes advantage of the automatic this binding performed by the arrow function, but instead of doing it as part of the class method declaration you can simply do it lazily at the time you need it to be bound.
Note, however, that doing it this way does mean that a new function will be created each time gameLoop is called.
When you call this.gameLoop() within start, the value for this inside gameLoop's body will be the class gameLoop belongs to, because you call gameLoop as a property of this (the class).
When you pass a function reference its value for this might be anything when the function is called from somewhere else.
Solution 1 | Using Function.prototype.bind
bind the value for this as you give the function to requestAnimationFrame. By doing this you explicitly say:
Let the argument to bind be this inside any call to gameLoop, regardless of how it is called, or where it is called from.
requestAnimationFrame(this.gameLoop.bind(this));
Note that bind returns you a new function, so the original gameLoop function that is still a property of your class remains unchanged.
Solution 2 | Using an arrow function
Define an arrow function to eventually execute the call to gameLoop instead of requestAnimationFrame. The this value within arrow functions is static, and is inherited from the execution context enclosing the function declaration.
requestAnimationFrame(() => this.gameLoop());
I have been dealing with this problem for days already. I am at my wits' end!
I can't seem to find a definitive answer anywhere on any of the forums, documentation, etc.
Everything looks fine at first run, or when I load a next level for the user to play. But if the user hits the ESC key to load a different level, the ENTER FRAME listener does not get removed and it duplicates all the triggers in it, showing the player going really fast, and all funky, because it builds on top of the previously instantiated ENTER FRAME listener.
I don't know if I have a problem of an anonymous function, or an unknown instance being referenced in my removeEvent... command... Bottom line, I give up and I need this working HELP!!!
Here's the code:
function initPlay():void
{
//code here determining what display object to add to the list and assign it to the currentLevel variable (a movieclip)
if(userIsLoadingOtherLevel){
removeEnterFrameListener();
addChild(currentLevel);
}
if(userIsGointToNextLevel)
addChild(currentLevel);
currentLevel.addEventListener(Event.ENTER_FRAME, onEnterFrame);
function onEnterFrame(event:Event):void
{
//collision detection, parallax scrolling, etc, etc is done here.
if(allCoinsCollected)
loadNextLevel();
if(ESCKeyPressed)
ESCKeyPressHandler();
}
function loadNextLevel():void
{
removeChild(currentLevel);
newLevelToLoad++
removeEnterFrameListener();
initPlay();
}
function ESCKeyPressHandler():void
{
removeChild(currentLevel);
initPlay();
}
function removeEnterFrameListener();
{
currentLevel.removeEventListener(Event.ENTER_FRAME,onEnterFrame)
trace("currentLevel.hasEventListener(Event.ENTER_FRAME) = "+currentLevel.hasEventListener(Event.ENTER_FRAME)); //outputs TRUE if called from loadNextLevel but FALSE if called from initPlay() !!!
}
}
I also tried to add and remove the eventListener to stage, MovieClip(Root), or nothing at all and the result is always the same.
I know that there may be other ways to design such a process, but please note I am not really flexible at the moment on doing this because the project is very long (about 4000 lines of code) and removing the ENTER FRAME this way, crazy or not should still work!!
THANK YOU in advance for anyone willing to help.
The problem appears to be the nested functions inside the initPlay() method.
Each time you call initPlay() you are defining new functions. Some of these nested functions call initPlay() themselves.
Functions are objects (memory references). So each time you call initPlay() you are making new references to new functions. So when you try to remove an event listener, you're only able to remove one of these event handlers (the one in the current scope of execution).
I'm not sure if I'm explaining this clearly, perhaps this example will help. I'll use numbers to represent the references to each function, and a simple scenario that is similar to yours:
function example():void
{
addEventListener(MouseEvent.CLICK, mouseClickHandler);
function mouseClickHandler(event:Event):void
{
if (someCondition)
{
example();
}
else
{
removeEventListener(MouseEvent.CLICK, mouseClickHandler);
}
}
}
When we run this function the first time, a new function is defined within the scope of the example() function. Lets use the number 1 to represent the reference to this nested function. someCondition is true on the first time around, and so the example() function is called again.
On the second execution of the example() function, a new reference to the mouse event handler is created (#2). We also add the event listener again. At this point, there are two event handling functions in memory, and both will be executed when the event is dispatched.
Let's say that in the second invocation of example() that someCondition is false and now we want to remove the listener. When we call:
removeEventListener(MouseEvent.CLICK, mouseClickHandler);
It's referring to event handler #2. Event handler #1 still exists, and because it's hidden in the scope of the first invocation of example() it can't be removed here.
My simple example breaks down after this... but I hope it makes it clear why your event handlers shouldn't be nested inside a function. Admittedly, this is difficult to describe and even more so in a real world example like yours. But I'm pretty confident that this is the source of most, if not all, of the issues you describe.
Here's how I was able to get around this without changing the scope of the nested functions (although I agree that would be the preferred solution) by creating a boolean variable called "loadingNewGame" and changing it to true from outside the onEnterFrame (in fact, this assignment was done from initPlay() and then from onEnterframe I called removeEnterFrameListener() function. This did the trick.
here's the code in case anybody is interested:
// package, and other code here.
var loadingNewGame:Boolean = new Boolean(false);
function initPlay():void
{
//code here determining what display object to add to the list and assign
//it to the currentLevel variable (a movieclip)
if(userIsLoadingOtherLevel)
{
loadingNewGame = true;
removeEnterFrameListener();
addChild(currentLevel);
}
if(userIsGointToNextLevel)
addChild(currentLevel);
loadingNewGame:Boolean = false;
currentLevel.addEventListener(Event.ENTER_FRAME, onEnterFrame);
function onEnterFrame(event:Event):void
{
if(loadingNewGame)
removeChild(currentLevel);
//collision detection, parallax scrolling, etc, etc is done here.
if(allCoinsCollected)
loadNextLevel();
if(ESCKeyPressed)
ESCKeyPressHandler();
}
function loadNextLevel():void
{
removeChild(currentLevel);
newLevelToLoad++
removeEnterFrameListener();
initPlay();
}
function ESCKeyPressHandler():void
{
initPlay();
}
function removeEnterFrameListener();
{
currentLevel.removeEventListener(Event.ENTER_FRAME,onEnterFrame)
trace("currentLevel.hasEventListener(Event.ENTER_FRAME) = "+currentLevel.hasEventListener(Event.ENTER_FRAME));
//outputs true
}
I have two function on my AS3 program, one fires when the width and height changes:
stage.addEventListener(Event.RESIZE, resizeListener);
function resizeListener (e:Event):void {
//some commands
}
And the second one fires one a number of milliseconds pass:
var myTimer:Timer = new Timer(clockUpdate, 0);
myTimer.addEventListener(TimerEvent.TIMER, updateData);
myTimer.start();
function updateData(e:TimerEvent):void {
trace("AUTOUPDATE");
trace(e);
}
I need to fires those function also manually, lets say when the user press a button, but i don't know what parameters i have to send them when they are called manually.
I tried just resizeListener() and updateData() but of course it fails asking me for the parameter.
You can make parameters in a function optional by providing a default value. This is an example by taking your two functions above and making the event parameters optional:
function resizeListener(e:Event = null):void {
//some commands
}
and
function updateData(e:TimerEvent = null):void {
trace("AUTOUPDATE");
trace(e);
}
Calling, for example, resizeListener() will now execute the function and the value of e will default to null.
Making the Event parameter optional, resizeListener(e:Event=null), as in walkietokyo's answer, is a perfectly valid and often convenient solution. Another alternative is to put the stuff you want to be able to do without the event being triggered in a separate function, that can be called by the event handler and from anywhere else.
So assuming for example that what you want to do on resize is to rearrange the layout, and you also want to do that same layout setup at initialization, or at the click of a button, or anytime really, you could do something like this:
stage.addEventListener(Event.RESIZE, resizeListener);
function resizeListener(e:Event):void {
rearrangeLayout();
}
function rearrangeLayout():void {
// The actual rearrangement goes here, instead of in resizeListener. This can be called from anywhere.
}
Which way to do it is probably a matter of taste or can vary from case to case, really, both works fine.
A benefit of separating things in an event handler and another function is that there will not arise a situation where you would have to check if the e:Event parameter is null or not. In other words, you would have code that is dependent on the Event, if any, in the event handler, and code that is independent of the Event in a more general function (not an event handler).
So in a more general and schematic case, the structure would be something like this:
addEventListener(Event.SOME_EVENT, eventListener);
function eventListener(e:Event):void {
// Code that needs the Event parameter goes here (if any).
// Call other function(s), for the stuff that needs to be done when the event happens.
otherFunction();
}
function otherFunction():void {
// Stuff that is not dependent on the Event object goes here, an can be called from anywhere.
}
This is my original pseudo code:
function1();
function1():void{
//do something
after mouseclick do function2
}
function2():void{
//do something
after animationfinish do function3
}
etc..
Can I get it into something like this?:
function1();
after mouseclick do function2()
after animationfinish do function3()
What is an easy way to get listeners on the top level?
If I understand your question correctly, when function1 is called you want to addEventListener(MouseEvent.CLICK, function2);
Are you using Actiosncript to animate or Keyframes?
I know with TweenMax you can add a function to call at the end of the tween. If using fl.Transtions.Tween you can listen for TweenEvent.MOTION_FINISH and then call function3. I don't mess much with the timeline in Flash, since I feel more in control with coding it, but I know you can add code at the last frame of an animation to call function3.
If I am completely missing you question feel free to clarify what exactly you are seeking.
If i good understand - You like to create functions chain .
I depends what You like to do , problem is in many possibilities.
For call few functions i use this class :
https://github.com/turbosqel/as3SupportLib/blob/master/as3SupportLib/src/turbosqel/utils/CountCall.as
You can also use deeper and more elastic way and add next callbacks to function :
var func:Function = function():void { // declare new function
... function body // your class actions
for each(var call:Function in arguments.callee){ // get functions
call(); // call function
}
}
func["someFunction"] = someFunction; // add function as dynamic value
func["otherFunction"] = anotherFunctionToCall; // add another function
func(); // call function
I want to run some code whenever a DisplayObject is added as a child to a DisplayObjectContainer.
Or to put in other words, to catch the addedToStage event of all DisplayObjects, even ones I don't know about.
Is it possible? and if not, any ideas on how to do something similar?
An 'added' event is dispatched whenever a child display object is added to the display list via addChild() or addChildAt(). In the DisplayObjectContainer class add the listener:
addEventListener(Event.ADDED, onAdded);
and the handler:
private function onAdded(e:Event):void
{
trace('number of children is now ' + numChildren);
}
Using Event.ADDED_TO_STAGE on stage Object and setting useCapture to true.
More info on event here
Example:
function onAdded(e:Event):void{
trace(e.target.toString()); //use target to get the Object added
}
stage.addEventListener(Event.ADDED_TO_STAGE, onAdded, true); // set capture to true
I don't know if there is a built in way to do this.
Alternatives include the obvious,
private var _num_children:Number = 0;
addEventListener(Event.ENTER_FRAME, _checkChildren, false, 0, true);
private function _checkChildren($evt:Event):void {
if (this.numChildren != _num_children) {
_num_children = this.numChildren;
// There was a child (or more) added in the last frame execution
}
}
However, this seems like a more elegant solution...
public function _addChild($do:DisplayObject) {
$do .addEventListener(Event.ADDED_TO_STAGE, _childAdded);
addChild($do );
}
private function _childAdded($evt:Event) {
// do whatever with $evt.target
}
The difference here, is the _childAdded will get fired for each and every child added via _addChild method. This means if you are doing some costly code execution you will be doing it once for each child instance.
If you use the first method, you are only calling the method once per frame, and if 10 images are added on a single frame, then it will only run once.