In JavaScript I can take anyOldObject and add anyOldObject["anyOldProperty"]="Test". I could do this in ActionScript 2 as well. Can I do it in ActionScript 3?
For example, I'm creating SoundChannel instances and I want to, say, assign IDs to them (e.g. soundChannel["id"]="123") or assign states. Will this still work, or will I have to create a separate associative array for each property (or create some new enclosing SoundChannelHolder class)?
You can do it on every class created as dynamic.
MovieClip is one of them.
Related
I'm new in AS3 and I wanna ask how to access variables inside MovieClips by its name.
in AS2 usually, I use its instance name followed by .(name of variable)
for example...
I have a variable named baru inside a MovieClip named my_mc.
usually I use my_mc.baru to reveal the value of the variable.
Now, i want to know how to do it in AS3
Thank you.
In AS3 there's a few separate but related things you need to be aware of:
All display objects (including MovieClip) can have a name property.
var mc:MovieClip = new MovieClip();
mc.name = "myMC";
myContainer.addChild(mc);
You can find a child by its name using getChildByName() on its parent.
var myMC:MovieClip = myContainer.getChildByName("myMC");
MoveClip instances can have dynamic properties that point to children (or anything at all).
myContainer.myMC = myMC;
(Note that other display object types, such as Sprite, do not allow dynamic properties. Instead you need to create a custom class with class properties.)
When you create a display object in code (as shown above), neither the name or a property on the parent will be automatically created. You can do it manually as shown above.
When you place a symbol instance in the authoring tool and give it an "instance name", both the name and a property on the parent symbol will be assigned by that "instance name". In this case you are not allowed to change the name in code.
Note that in AS2 using createEmptyMovieClip or attachMovie would assign the _name and create a property on the parent, but there's no AS3 equivalent to these functions. This is where a lot of confusion can come in.
So as you can see the way this works is really not different than AS2, except that AS2 had functions that did several things for you (create and add the MovieClip, set the name and add a property on the parent). The problem with AS2 was that you couldn't re-parent an object after it was created, which was a big limitation. In AS3 you can freely move things around.
If you just like to write code inside the MovieClip but not a *.as,you have to add a TextField in the MovieClip by hand,set it's type to Dynamic,then type the variable string in it,then get it use: MovieClip.TextField.text and don't forget: TextField.alpha=0.
It is not a wise way.
i am working with several nested movieclip objects in a project. but i get into trouble with the buttons i created and implemented in the nested movieclips:
to describe it in a simple way:
I have a main movieclip with five frames, including two buttons with listeners to browse between the frames. Then inside of one Frame I have another movieclip with its own buttons. i instanciated it by hand not through code and gave it a specific name like "nestedMc".
Now I dont want to build the Listeners for those buttons inside the class of the nested movieclip class but in its parent class, which works fine until i then goto another frame in the main movieclips timeline and come back.
obviously every time flash enters a frame its contents get created anew (and therefore get new instance names). I could now try solve this through filling the frames via code.
But maybe there is another way to make sure the frame contains the same instance everytime i enter?
Timeline scripting is a dirty business, and really, a carry-over compatibility layer for Actionscript 2 projects. Whenever possible, I highly recommend not doing it, and simply keeping all of your code in your document class. As you're experiencing, timeline code causes headaches.
Consider instead just creating both states of your Stage (it sounds like that's what your two buttons are jumping between) and simply hiding them offstage or setting their alpha to zero and their mouseEnabled state to false. Furthermore, if the purpose of your frames is to play animation (a tween), consider instead switching to a much more powerful suite such as TweenLite. Moving an object over a hundred pixels (smoothly) can be as easy as:
TweenLite.to(redBall, 3, {x:100});
Now, if you're manually adding these items to the stage, as long as the object is a dynamic one, you can assign an instance name to it which will be saved between frame loads. Be aware the object name is not the same as the instanced name. For example:
var redBall:Ball = new Ball();
redBall.name = "bubbles";
The object's name is Ball, but it's represented as a variable called redBall. Its actual DisplayList name will likely be ambiguous (such as "Instance71"), and I can manually define it as "bubbles". 3 different names for the same object, all very different and necessary.
Even if you give the object a displayList name, you may not be able to reference it through code unless you enable Automatically declare stage instances, which basically creates on each object a pointer to the displayList object.
That said, you can always fetch the object by other means. Obviously, your buttons are always appearing, but you're trying to find a very specific object on the stage. At this point, we can use getChildByName() or getChildAt().
Hope that helps.
-Cheers
I'm new to coding and AS3. I was reading about adding things to the stage using AS3 and learned about the addChild method. Reading more I found that there are different ways to use it. I also read that some ways are better than others, and that some ways are not good at all and better avoided.
I don't trust those sources though. As a coding newbie I come asking for help, StackOverflow. I'm about to start an addChild heavy project and I want to start it with the right implementations. I trust you, so let me ask you this: What's the correct use of addChild?
I just want to add things to the stage, but I read that it's not good to add them directly to the stage (without further argument though).
stage.addChild()
this.addChild()
addChild()
Are there other ways? Which one should I use?
Thanks for your time. :)
As the top-level container for all display objects in the display list hierarchy, there is only one Stage no matter how many SWF files are loaded into the runtime. So, generally, objects should not be added to the Stage, directly, at all. The only object the Stage should contain is the root object.
Generally, you should not use: stage.addChild()
Adding a DisplayObject to the display list should be performed within the scope of a DisplayObjectContainer.
Each SWF file has an associated ActionScript class, known as the main class of the SWF file which extends a display object. From this class or any child within the hierarchy you may call addChild().
The following are equal, and would add a child within the scope of the current display object container.
this.addChild()
addChild()
The this keyword explicity defines scope; however, is generally implicit when left off.
While a display object added via addChild() is added to the front (top) of all other children, to add a child to a specific index position, use the addChildAt() method.
References:
Display Programming
Basics of display programming
Adding display objects to the display list
When do we need to pass reference to the stage from one as3 class to another like in this tutorial
http://asgamer.com/2009/as3-flash-games-for-beginners-firing-weapons-with-delays
he added a ref to the stage from the bullet class to the ship class
as I understand a reference is needed when we want to use a function in a certain class from another class but why do we have to reference the stage isn't it only one stage for the whole project or each class has it's own stage ?
I am very confused
Thanks
Only objects that are connected to a stage will be shown on screen. In the tutorial he is adding the lasers onto the stage display list so that it appears on screen. Until it is added, it will not be rendered regardless of the visible property.
See this for more info about the display list.
#Geotarget is correct, but the answer is a little bit indirect.
Objects that are not on the display list do not actually have a reference to stage. So if, for example, you create a var mc:MovieClip = new MovieClip(); which is not added to the display list (as in addChild(mc)), then mc.stage will be null. (Also, checking if(mc.stage){[...]} is also a way to verify if the MovieClip is part of the display list yet.)
So you can pass a reference to the stage to non-display-list objects to allow them access to things like stageWidth.
Yes, a reference is needed when you wanna have to access a function present in that particular class ( to which reference belongs). This is one of the uses.
There is only one stage for the whole project.
In the tutorial you are following, both the classes are using the reference of a COMMON Stage, so that both of them can access the Stage.
It's like giving the address of a place to two people. So that both of them can go there. Naturally, giving addresses doesnot mean, we are building two places for each of them.
V.
I know I can create an actionscript loop in a script block that can create an array of objects. The problem is when doing that I don't know how to have those objects interact with the overall layout structure of the mxml document itself. They just default to 0,0.
What If I wanted to arrange a loop of dynamically generated objects inside of a tilegroup and under another dynamically generated item using actionscript for instance? (without individually specifyin x&y)
I need to know how to give them an automatic layout (like horizontal) and then determine where they fall in the order of other objects declared via mxml?
You can just add them as elements to the container group of your choice, just use:
myVGroup.addElement( myComponent );
Inside your loop. Where myVGroup is a VGroup that already exists in your layout.
You may also find this of interest. http://evtimmy.com/2009/06/flowlayout-a-spark-custom-layout-example/