is it possible to obtain the instance name of a class from the class without having to manually pass the instance name as a string parameter to the class constructor?
//Create New SizeClass
var big:SizeClass = new SizeClass();
//-------------
package
{
public class SizeClass
{
public function SizeClass()
{
trace( //-- Instance Name "big" --// );
}
}
}
No, it is not possible to know anything about the containing code block during a constructor, save what you can learn from the stack trace (though that's not available except in the debugger version of Flash). Even if you had a global access point for the containing class, it still would not allow for that access.
Think of a constructor like a method call. In a line of AS, it will be called before the assignment. Eg: var a:Foo = new Foo() the Foo is created (the constructor completes), and then a is populated with whatever just happened. After that point a will remain agnostic of its context (because of encapsulation) unless it is told about it (this is even true on a DisplayObject -- try this( var mc:MovieClip = new MovieClip(); trace( mc.root ) //this will be null ).
I'm keeping this because it is useful albeit not useful to your original answer.
You can always get the name of a class with getQualifiedClassName from the flash.utils package. You can't get a DisplayObject's until well after it has been constructed, but you can simulate this by (I believe) overriding function set name( value:String ):void. If that doesn't work, then try finding it after Event.ADDED and/or Event.ADDED_TO_SAGE.
The instance name isn't very important. You'd better store references of the instances inside an array.
var sizes:Array = new Array();
var big:SizeClass = new SizeClass();
sizes.push( big );
When you want to access them, you can loop through the array.
for (var i:uint = 0; i < list.length; ++i)
{
var size:SizeClass = list[i] as SizeClass;
trace( size );
}
BTW: Instead of an instance name it is possible to add an automatic index to your class.
package
{
public class SizeClass
{
private static var global_index:int = 0;
public const INDEX:int = global_index ++;
}
}
Which you can access like this:
var big:SizeClass = new SizeClass();
trace(big.INDEX) // 0
var small:SizeClass = new SizeClass();
trace(small.INDEX)// 1
source: http://blog.stroep.nl/2010/08/auto-increment-as3-class/
Related
I got a .fla file, where inside I have some movieclip instances placed in the scene. I need to iterate through them and gather some data, like position, name, and custom properties.
These custom properties, I don't know how to pass them, I know one way that works so far is to use the accessibility properties panel (Flash Pro CC), and then in the code I can just read them. However there should be a better way I assume.
If I have understood correctly your question and what you have said in your comments about the answer of #Aaron, you have an swf file, which you load dynamically, and you want to get/set some of its MovieClips properties, if it's the case, take this example :
MyMC.as :
public class MyMC extends MovieClip
{
private var timer:Timer;
private var rotation_speed:int = 1;
public function MyMC() {
}
public function set_Rotation_Speed(_rotation_speed:int): void {
this.rotation_speed = _rotation_speed;
}
public function get_Rotation_Speed(): int {
return this.rotation_speed;
}
public function start_Rotation(): void {
this.timer = new Timer(500, 10);
this.timer.addEventListener(TimerEvent.TIMER, on_Timer);
this.timer.start();
}
private function on_Timer(e:TimerEvent): void {
this.rotation += this.rotation_speed;
}
}
Then, in my swf.swf I have an instance of that MovieClip.
I loaded the swf.swf using this code :
var loader:Loader = new Loader()
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, on_SWFLoad);
loader.load(new URLRequest('swf.swf'));
And to set/get some of my MovieClip properties, I did :
function on_SWFLoad(e:Event): void
{
var swf:DisplayObjectContainer = DisplayObjectContainer(loader.content);
var num_children:int = swf.numChildren;
for(var i:int = 0; i < num_children; i++)
{
var child:MovieClip = MovieClip(swf.getChildAt(i));
// get the name
trace('name : ' + child.name);
// set the position
child.x = child.y = 100;
// get the class name, in my case it's MyMC
var class_name:String = getQualifiedClassName(child);
// get all the details of the child
trace(describeType(child));
child.set_Rotation_Speed(45);
child.start_Rotation();
trace(child.get_Rotation_Speed()); // gives : 45
}
addChild(loader);
}
You can use the describeType() function To get all the properties of your instance.
Hope that can help.
First of all, you can set properties on timeline instances from code. There's nothing special about this. For example:
Place an instance of a library symbol on a keyframe
Give it an instance name in the Properties panel, for example "myInstance"
On the same keyframe put some code that refers to it, such as myInstance.color = "red"
You can also create and assign custom properties by making the symbol a component:
Right-click on the symbol in the library and choose "Component Definition"
Add custom properties in the Parameters table. It's now a component symbol.
On the timeline, place an instance of the symbol and use the Properties panel to set its parameters.
You can do a lot more with components if you want, such as live preview and compiled components. More info can be found here here: http://www.adobe.com/devnet/flash/learning_guide/components/part03.html
public function create():ArrayCollection{
var index:int = 0;
var data:ArrayCollection = new ArrayCollection();
var length:int = originalData.length;
for(index; index < length; index++){
data.addItem(originalData[index]);
}
return data;
}
originalData is the original state of my data from database.
data is a copy of originalData used to be manipulated as the provider for my List component.
There's a button I use to call the create() function above, that
would mean, I want to revert all changes in data, and go back to
everything I have in originalData.
But when I debug my function, originalData has all the changes made in data.
When I use
list.selectedItem.thing = "new string";
is supposed to modify data[index].thing, because data is my List.dataprovider. but it changes originalData[index].thing also and this collection wasn't used for anything, except for creating a copy of itself!
I don't know why this happens. I didn't know how to phrase this behaviour as a google query.
Please, if you don't understand the question, comment it so I can try and make it clearer. This has consumed more time than its functionality is worth.
EDIT:
I've also tried this, but it doesn't work:
public function create():ArrayCollection{
var index:int = 0;
var data:ArrayCollection = new ArrayCollection();
var length:int = originalData.length;
for(index; index < length; index++){
// initializing a Item object.
var dataItem:Item = new Item();
dataItem = originalData[index] as Item;
data.addItem(dataItem);
}
return data;
}
EDIT 2:
Based on your answers and some research I came up with this generic function to copy arrayCollections made of custom objects.
public static function copy(objectClassName:String, objectClass:Class, arrayCollection:ArrayCollection):ArrayCollection{
var index:int = 0;
var length:int = arrayCollection.length;
var copy:ArrayCollection = new ArrayCollection();
for(index; index < length; index++){
registerClassAlias(objectClassName,objectClass);
copy.addItemAt(ObjectUtil.copy(arrayCollection.getItemAt(index)) as objectClass,index);
}
return copy;
}
As Tom says, this is because AS3 passes by reference. If you don't want to modify the original values then you should, again as Tom says, create copies of them.
Fortunately, AS3 has a utility to do this -- ObjectUtils.copy. Try this code instead of your original:
public function create():ArrayCollection{
var index:int = 0;
var data:ArrayCollection = new ArrayCollection();
var length:int = originalData.length;
for(index; index < length; index++){
data.addItem(mx.utils.ObjectUtil.copy(originalData[index]));
}
return data;
}
Do take note that copy() returns a generic Object. If you want to access any of its properties in a type-safe manner you'll have to cast it to its type.
A bit more about the pass-by-reference deal. Let's say we have items a, b, and c floating around in memory. You put them into an array(originalData). originalData now contains references to a, b, and c. You then create an ArrayCollection and insert (again) references to a, b, c. Objects a, b, and c aren't what's being stored in either the array or the ArrayCollection. So when you update originalData[0] you're getting a reference to an object (a), and updating it.
Likewise when you update ArrayCollection.getItemAt(0) you're getting the same reference and updating the underlying object which is why you're getting the behavior you're getting. Making a copy and inserting it means you're referencing an entirely new object.
I am not used to actionscript, but it looks to me like you are putting references to objects from one arrayCollection to another arrayCollection. So if you change those objects, this will be reflected in both arrayCollections since they refer to the same objects.
To avoid this you should make copies from the original objects to put in the new arrayCollection.
To create a deep copy of an array and keep the type, use the following method:
public static function clone(source:Object):*
{
var myBA:ByteArray = new ByteArray();
myBA.writeObject(source);
myBA.position = 0;
return(myBA.readObject());
}
This is the way proposed by Adobe.
Update: idea for a type safe copy function
public static function copyTypeSafe( ac:ArrayCollection ):ArrayCollection
{
var cloneAc:ArrayCollection = new ArrayCollection();
if( ac.length == 0 ) {
return cloneAc;
}
var className:String = getQualifiedClassName( ac.getItemAt(0) );
registerClassAlias( className, (getDefinitionByName( className ) as Class ) );
for each (var obj:Object in ac)
{
cloneAc.addItem( ObjectUtil.copy( obj ) );
}
return cloneAc;
}
You need to do a registerClassAlias call for each of the classes inside of your collection, then just use the function clone with the ByteArray suggested above and it will work fine. The key is to do a registerClassAlias call for each type inside of the ArrayCollection which you want to maintain. In my case:
var productGroupClassName:String = getQualifiedClassName(ProductGroup);
registerClassAlias( productGroupClassName, ProductGroup );
var productClassName:String = getQualifiedClassName(Product);
registerClassAlias( productClassName, Product );
//Need to create a copy so the original values will not be altered
dataProvider = copyTypeSafe(EnalityData.productsInfo);
var test:*;
test = sMC // Some movieClip exported for ActionScript
var f = new test;
Sorry if the question's a bit lame, but I begin to wonder, what does this asterisk, and the snippet mean?
Answering your original question and your question asked in a comment:
An asterisk is a wildcard which means the variable will accept any type of info. Example:
var wildcard:*;
wildcard = "hello";
wildcard = 10;
wildcard = new MovieClip();
All of the above will work.
Variables should be typed as strictly as possible; by this I mean that when you want to assign a MovieClip to a variable, your variable should be typed as a MovieClip. Like so:
var mc:MovieClip = new MovieClip();
This works for anything. If you create your own class, then use that as your type for a variable that holds your class.
var thing:MyClass = new MyClass();
An error will be thrown if you try and assign an unrelated type to a variable, like so:
var thing:MovieClip = "hello";
But as long as your variable type is somewhere along the inheritance chain of what you're assigning to it, then it will work.
var thing:DisplayObject = new MovieClip();
This can be handy if you want to loop through an array containing an assortment of your own classes that extend MovieClip.
var ar:Array = [];
/**
* MyClass extends MovieClip
* MyOtherClass extends MovieClip
*/
ar.push(new MyClass());
ar.push(new MovieClip());
ar.push(new MyOtherClass());
var i:MovieClip;
for each(i in ar)
{
trace(i);
}
Overall the wildcard type is not a recommendation. At worst use Object as everything in flash extends this. One situation where a wildcard or Object can be useful is if you want to create a function that can accept any kind of data. Like so:
var myarray:Array = [];
function addToArray(data:Object):void
{
myarray[myarray.length] = data;
trace(data);
}
OR
function addToArray(data:*):void
{
myarray[myarray.length] = data;
trace(data);
}
Hope this all makes sense.
The asterisk means the variable type is undefined, or a wildcard.
Meaning you can define test as any sort of variable.
I have the following function to set up cards in a game. I created one array to hold the kind of cards, and another array to hold the position of the cards.
private function setPlayerCard(cardNumber:int, cardPos:int):void{
for (var i:int = 1; i < _CardGridInstance.numChildren+1; i++) {
var _position:MovieClip = MovieClip(_CardGridInstance.getChildByName("Position_" + i));
cardPositions[i] = _position;
cardPositions[i].pos_name.text = "position" + i;
cardPositions[i].id = ["pos"+i];
}
for (var j:int = 1; j < numCards+1; j++) {
var _c:Class = getDefinitionByName("Card_" + j) as Class;
var _cardInstance:MovieClip = new _c();
cards[j] = _cardInstance;
}
cards[cardNumber].x = _CardGridInstance.x + cardPositions[cardPos].x - 1;
cards[cardNumber].y = _CardGridInstance.y + cardPositions[cardPos].y;
addChild(cards[cardNumber]);
}
So if I want to set the card number "3" in position "5" I just write:
setPlayerCard(3,5);
The problem I can see is that every time I'd like to place a card, I am creating two arrays every time. I would like to make the arrays "global" (i.e. create it in my constructor in my document class) and reuse it in the function "setPlayerCard" however I am getting errors when I try to do so.
Any suggestions?
This is a perfect case for a Singleton static class data model. You can get the instance of the Singleton from throughout the application as it is a static class, and it can contain the two arrays without duplication.
pixelbreaker has a nice basic Singleton AS3 example that you can build from.
It's a little difficult to answer accurately without knowing how you are creating the variables and what errors you're getting. Can you post the entire class and the errors?
I can, however, recommend that you do not use the Singleton pattern. This is not a perfect case for a Singleton. The Singleton pattern has no place in OOP, it's procedural programming wrapped up like OO, but that's an argument for elsewhere.
This is, though, a perfect case for a class level variables. The following is a simple example. There are a few missing variable declarations though (numCards), as I don't know where you're creating and setting them.
package{
import flash.display.Sprite;
public class CardGame extends Sprite{
private var cardPositions:Array = new Array();
private var cards:Array = new Array();
public function CardGame(){
for var i:uint = 1; i <= _CardGridInstance.numChildren; i++) {
var position:MovieClip = MovieClip(_CardGridInstance.getChildByName("Position_" + i));
cardPositions[i] = position;
cardPositions[i].pos_name.text = "position" + i;
cardPositions[i].id = ["pos"+i];
}
for(i = 1; i <= numCards; i++) {
var c:Class = getDefinitionByName("Card_" + i) as Class;
var cardInstance:MovieClip = new c();
cards[i] = cardInstance;
}
}
private function setPlayerCard(cardNumber:uint, cardPos:uint):void{
cards[cardNumber].x = _CardGridInstance.x + cardPositions[cardPos].x - 1;
cards[cardNumber].y = _CardGridInstance.y + cardPositions[cardPos].y;
addChild(cards[cardNumber]);
}
}
}
This way you only create and populate the arrays once and you can access them from anywhere within the CardGame Class. They are not global but they are within the scope of the setPlayerCard method.
You may get errors as objects might not be instantiated when the Document Class' constructor gets called, but that can be worked around.
What is the need for the variable to be public and static?
Static means that the variable is on the Class, not instances of the Class. So every "CardGame" instance will share the same static variable. I presume, because this is the Document Class, that you will not have more than one instance of it. So there is no reason for that.
The only other reason, because you declared it public, is to make the variable accessible from outside the Class through CardGame.cardPositions. This is bad practice as you shouldn't allow other objects to directly manipulate a Classes internal data. That breaks encapsulation. Since this is the Document Class and the top of the hierarchy, you should pass a copy of the data to whichever object needs it and wait for an event to retrieve the updated data. That way you can sanitise the data before using it and you're not just blindly trusting other objects to respect your data.
http://en.wikipedia.org/wiki/Encapsulation_(object-oriented_programming)
I tried using the Singleton class, but since I had to reference MovieClips that were already on the display list, I opted for a different solution from "Actionscript 3 Tip of the Day":
http://www.kirupa.com/forum/showthread.php?p=2110830#post2110830
package {
public class ClassName {
public static var myArray_1:Object = new Object;
public static var myArray_2:Object = new Object;
public function ClassName() {
//constructor
Whatever();
DoStuffWithWhatever();
}
private function Whatever() {
// put stuff into the array here
}
private function DoStuffWithWhatever():void {
// do stuff with the array values here.
}
}
}
So, in short, my problem is this. I am using a variable which is a movieclip loaded from an external swf. I want to "spawn" multiple instances of the movieclip that all react to the same code, so for example if I say var1.x = 100, they all are at 100x. But my problem is when I run addChild(var1) multiple times(I'm not actually typing in addChild(var1) over and over, I just have it set to add them at random times), the new child just replaces the old one, instead of making multiple movieclips. Should I do something like
var var1:MovieClip
var var2:MovieClip = new var1 ?(which doesnt work for me btw, gives me errors)
Oh, heres the code, and also, I am pretty new to as3 fyi, still don't even know how arrays work, which was my second guess to the problem.
var zombieExt:MovieClip;
var ldr2:Loader = new Loader();
ldr2.contentLoaderInfo.addEventListener(Event.COMPLETE, swfLoaded2);
ldr2.load(new URLRequest("ZombieSource.swf"));
function swfLoaded2(event:Event):void
{
zombieExt = MovieClip(ldr2.contentLoaderInfo.content);
ldr2.contentLoaderInfo.removeEventListener(Event.COMPLETE, swfLoaded2);
//zombieExt.addEventListener(Event.ENTER_FRAME, moveZombie)
zombieExt.addEventListener(Event.ENTER_FRAME,rotate2);
function rotate2 (event:Event)
{
var the2X:int = playerExt.x - zombieExt.x;
var the2Y:int = (playerExt.y - zombieExt.y) * 1;
var angle = Math.atan(the2Y/the2X)/(Math.PI/180);
if (the2X<0) {
angle += 180;
}
if (the2X>=0 && the2Y<0) {
angle += 360;
}
//angletext.text = angle;
zombieExt.rotation = (angle*1) + 90;
}
playerExt.addEventListener(Event.ENTER_FRAME,spawn1);
function spawn1 (event:Event)
{
if(playerExt.y < 417)
{
var someNum:Number = Math.round(Math.random()*20);
if(someNum == 20)
{
addChild(zombieExt)
zombieExt.x = Math.round(Math.random()*100)
zombieExt.y = Math.round(Math.random()*100)
}
}
}
}
addChild() does not create new instances. It is used to add an already created instance to the display list. If you call addChild() multiple times on the same instance then you are just readding itself.
Also each instance is unique, you can not globally change the x position of an instance by changing another one of them. What you would do is as Henry suggests and add each new instance of a MovieClip into an array, then whenever you change something you can loop through the array and apply the changes to each instance.
You can not go var2:MovieClip = new var1 either since var1 is an instance and not a class.
Here's a different method of receiving loaded MovieClips, which i use when i need many copies of the item.
in the swf you are loading, give the target movieclip a linkage name in the library, for this example i will use "foo"
private var loadedSwfClass:Class
private var newZombie:MovieClip;
private var zombieArray:Array = new Array();
function swfLoaded2(event:Event):void
{
loadedSwfClass = event.target.applicationDomain.getDefinition("foo");
for(var n:int = 0; n<100; n++){
newZombie = new loadedSwfClass()
zombieArray.push(newZombie);
addChild(newZombie);
}
}
as per this tutorial
http://darylteo.com/blog/2007/11/16/abstracting-assets-from-actionscript-in-as30-asset-libraries/
although the comments say that
var dClip:MovieClip = this;
var new_mc = new dClip.constructor();
this.addChild(new_mc);
will also work.
It sounds like you might be accessing the same instance some how in your code. It would be helpful to see your code to figure this one out.
If I wanted to load in one swf files and add a MovieClip multiple times I would place it in the library of that SWF file. And then instantiate it and store it into an object pool or a hash or some list.
// after the library were finished loading
var list:Array = [];
for(var i:int=0; i<10; i++) {
var myCreation:MySpecialThing = new MySpecialThing();
addChild(myCreation);
list.push(myCreation);
}
where my library would contain a linkage to the class MySpecialThing.
Calling addChild(var1) multiple times on the same parent doesn't have any effect (unless you have added another child to the same parent in between, in which case it will change the child index and bring var1 to the top). If you call it on different parents, it will just change the parent of var1, doesn't duplicate. Call addChild(new MovieClassName()) at random times instead to add new copies of it. Use an array as suggested here to access them later.
Wow, thanks there henry, just using an array did exactly what I needed, and made things alot simpler.
when you load in using a loader you only get 1 instance, however you can do some funky reflection to determine what class type the given loader.content is, and then instantiate them using that. For Example:
var loader:Loader = new Loader();
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, loader_completeHandler);
loader.load(new URLRequest("ZombieSource.swf"));
var classType:Class;
function loader_completeHandler(evt:Event):void
{
var loadInfo:LoaderInfo = (evt.target as LoaderInfo);
var loadedInstance:DisplayObject = loadInfo.content;
// getQualifiedClassName() is a top-level function, like trace()
var nameStr:String = getQualifiedClassName(loadedInstance);
if( loadInfo.applicationDomain.hasDefinition(nameStr) )
{
classType = loadInfo.applicationDomain.getDefinition(nameStr) as Class;
init();
}
else
{
//could not extract the class
}
}
function init():void
{
// to make a new instance of the ZombieMovie object, you create it
// directly from the classType variable
var i:int = 0;
while(i < 10)
{
var newZombie:DisplayObject = new classType();
// your code here
newZombie.x = stage.stageWidth * Math.random();
newZombie.x = stage.stageHeight * Math.random();
i++;
}
}
Any problems let me know, hope this helps.