So i have narrowed down my problem to this:
i have two instances of a movieclip ("content1", "content2") added into two different other movieclips ("container1", "container2"). I want to remove them.
As soon as i remove one of them with this horrible command...
MovieClip(MovieClip(root).getChildByName("container1")).removeChild(MovieClip(MovieClip(root).getChildByName("container1")).getChildByName("content1"));
...the other instance of it changes its instance name to a generic one (like "instance25") and i can't access it anymore with getChildByName.
Can anyone explain this please?
I've never experienced that behaviour - regardless, what you can do is store reference to both before you remove them. This way, you won't need their original instance name to remove both:
var top:MovieClip = root as MovieClip;
var cotainer:MovieClip = top.container1;
var content1:MovieClip = container.getChildByName("content1");
var content2:MovieClip = container.getChildByName("content2");
container.removeChild(content1);
container.removeChild(content2);
Hopefully this answer gives you some hints for making your code much more readable as well.
Related
I am completing an online tutorial and manipulating it suit my website. I've come across this code...
`// Create a menu item movie clip in the menu_mc instance on the main timeline
// for each item element offsetting each additional further down the screen
var item_mc = menu_mc.attachMovie("movieitem","item"+item_count, item_count);
item_mc._x = item_count * item_spacing;
item_count++;`
The following line gives me a problem (the method is no longer supported)
var item_mc = menu_mc.attachMovie("movieitem","item"+item_count, item_count);
How can i achieve this?
I've tried the following with no joy. message too many arguments?
var mItem:movieitem = new movieitem;
var item_mc = menu_mc.addChild(mItem,mItem+item_count, item_count);
addChild() only accepts 1 argument, which is the display object itself. Also, it looks like you're missing brackets when you create your object and by convention, class names are capitalised.
var mItem:movieitem = new movieitem();
Edit based on my comment
Looking at the documentation for attachMovie() for AS2 (wow, been awhile since I've looked at this), it takes in 3 arguments:
id:String, name:String, depth:Number
Now the id is used to grab a movieclip from the library. This is no longer needed as you've already created a movieclip object from your library in the line before:
var mItem:Movieitem = new Movieitem();
The second argument name is used to create a unique instance name for the created moviclip from the library. You don't really need this. In the line where you create the movieclip (see above), you already have a unique reference you can use to access the movieclip. Interestingly, attachMovie() also returns a reference -I've never ever found a use for the instance names given with the 'name' argument. I just use the reference returned to access it, which you are already doing.
The third argument depth determines which depth the movieclip is placed at. In your case, I am guessing that ' item_count' is just a number that increases, which effectively puts that movie clip at the highest depth when that line is executed. By default, addChild() will automatically do this for you and put the display object (your movieclip) at the highest depth within the parent at the time it is added. So, unless you wanted it at a specific depth/overlapping order, you don't really need to pass this in either. If you did want to add something at a specific depth, look at addChildAt()
Hence as mentioned before, you can just pass in the reference to your movieclip/display object in to addChild().
I've just started to learn actionscript for a month or so, and I've been stuck on this part of the code for about 2 days now ><
So basically, I wanted to write a hitTestObject in a movieclip ("fire_mc") to detect if it overlaps the the child I added on stage (enemy)
So here's what I wrote in the main stage...
var newtarget:enemy=new enemy();
stage.addChild(newtarget);
newtarget.x=40;
newtarget.y=30;
and every time I traced the newtarget in the fire_mc, it turns out to be NULL...
So should I be tracing enemy or newtarget? (Cuz I tried both and nothing works).
And how can I hitTestObject in the fire_mc movieclip?
Is it possible for me to hitTestObject newtarget if I were to create multiple newtarget-s?
If not, what should I do?
And can someone tell me the difference between root, and MovieClip(root) (Because sometimes in a movieclip I have to use the former one to work, and sometimes the latter, and I have no idea why cuz I'm all referencing to the same place)
Sorry for these simple and lengthy questions, I'm really just a noob and I tried looking up for answers in the web for hours, but nothing helpful turned up><
Thanks in advance :)
In this statement
var newtarget:enemy=new enemy();
var - keyword used to define varibles, newtarget - variable name in which pointer to new class instance stored, :enemy - data type (the class name), new - keyword used to create new class instances, and finally enemy is class constructor (by the way there is a rule of good manners by which class names are capitalized)
So answer for you question which should you use when you want check is some is overlapping is 'newtarget'.
Now about hit test - all you need do to check if two objects hit each other is correctly use their references from the part of project where your code is writen.
For example if you have your fire_mc on MainTimeline created by IDE, and code of creation of you enemy instance stored in newtarget sameplace, then if you check will be placed in frame of MainTimeline where both object present it will be like this
fire_mc.hitTestObject(newtarget);
or this
newtarget.hitTestObject(fire_mc);
All these statements give you same result - if objects intersect each other you have true returned.
If you created 'newtarget' on MainTimeline and checks will be from fire_mc (which is on MainTimeline to) frame, then code will something like that
this.hitTestObject(MovieClip(root).newtarget);
Now about root. Primarily it is a property of DisplayObject in which reference to the top-most display object in swf-file structure is stored. So as such it is inherited by all child classes. So here's the trick. When you try get your objects in swf structure using root here the differences are based on the fact that root always return object as DisplayObject and that means what if you object contains something that DisplayObject shouldn't you can't get it. So you must convert returned reference to need data-type usign MovieClip(...).
I think of 2 approaches referring to some visual element like movieclip. So suppose i have b_mc ( name="b") lying inside a_mc on the stage :
1st approach :
var mc:MovieClip = a_mc.b_mc
2nd approach :
var mc:MovieClip = a_mc.getChildByName("b")
I generally use 1st approach. What can be good reason to go for 2nd approach. It sometimes seems useless to me, as it involves extra overhead to name the movieclips, when used dynamically.
Thanks
V.
a.getChildByName('b') is slower than getting a.b.
If you don't need to use names it makes no sense to use it, however some programmers might make use of the name, especially when generating content dynamically rather than through the Flash IDE, in which case having this function is helpful, so that the display list doesn't have to be traversed by a custom function (which it does with internal function anyway, ergo it is slower than a.b)
getChildByName is needed if you add something dynamically to a movieclip. For instance:
var mc1:MovieClip = new MovieClip();
var mc2:MovieClip = new MovieClip();
mc2.name = "foobar";
mc1.addChild(mc2);
trace(mc1.foobar); //undefined
trace(mc1["foobar"]); //undefined
trace(mc1.getChildByName("foobar")); //[object MovieClip]
I usually do mc1["foobar"] when referencing objects since that way it's easy to work with items such as mc1["foobar_" + i];
I rarely never use getChildByName since that requires a manual cast whenever you try to pass something as a movieclip/textfield or whatever :)
However, if you do create the instances from the flash editor, then I would usually reference them through some exported class and access them through
mc1.mc2.mc3.optionsView.visible
If you have a list of objects that you need to go through programmatically, getChildByName is great. It would assume you've also named them in some programmatic way to reindex them in the for loop. I can also think of a couple other good ways to use this, like pushing the names or objects in an array, so they wouldn't have to be related, just all have some property or method in common.
for(var i:int = 0;i<numOfMC;i++) {
theParent.getChildByName("child"+i).doSomething();
}
I'm learning flex/flash and I'm lost on this one. I have used the "data" in a bunch of views and it works fine. For some reason it isn't working here.
I set a field to a string here:
function LoginLoaded (e:Event):void {
trace(e.target.data);
var ServerReturn:String;
ServerReturn = new String(e.target.data);
data.UserCommonReturnData = ServerReturn;
navigator.pushView(CommonPlaces, data);
}
and here in the common places view I try to load it back:
var CommonPlacesData:String = new String();
var CurrentSelect:String = new String();
CommonPlacesData = new String(data.UserCommonReturnData);
This gives the error "Access of undefined property data" I don't get it because calling on something like data.PickUpTime (also a string) works fine in other views.
The data begins in the first view like this:
[Bindable] public var User:ObjectProxy = new ObjectProxy();
User.ID = "2314084";
navigator.pushView(TaxiNowOrLaterView, User);
then in later views I call on it like this: (works fine)
var PickUpString:String = new String(data.ID);
Any help would be great!! Thanks!!!
There are few things about your code. First, you really should make it a habit to name the identifiers as appropriate to the language. Identifiers that start with the capital letter and subsequently use minuscule letters for the rest of the logical part of the word (system alternatively known as PascalCase) is employed to only name classes. The rest of identifiers should use camelCase (similar to PascalCase, but the first letter isn't capitalized)**. This greatly reduces the effort at understanding your code. A seasoned AS3 programmer would interpret your code as follows:
// Static constant (!) ID of the class User is assigned (?) a value of "2314084"
User.ID = "2314084";
// invoke a method pushView of a local variable navigator with arguments
// of which first is the class TaxiNowOrLater, the second is the class User
navigator.pushView(TaxiNowOrLaterView, User);
while, perhaps, you didn't mean it.
new String();
In the context of AS3 makes no sense at all. Strings are never references, are immutable and have literal syntax the majority of programmers agreed upon. The code above is identical to "". In the similar way, new String(anotherString) has exact same effect as anotherString.
Your question: event.target may be many different things, some of them may have property called "data" and some may not. The general approach to this problem is that you need to cast the value of event.currentTarget or event.target to the type you expect to dispatch the event. Suppose you are expecting an event from an instance of a Button class, then:
private function clickHandler(event:MouseEvent):void {
if (Button(event.currentTarget).enabled) // do things
}
This will not protect you from an error, if the same event was dispatched by an object, which is not a button, but will make the error reporting more conscious, because it would tell you what class was it trying to cast to what other class, when it failed.
If your program logic requires that the handler be aware of events it shouldn't handle (why?) you could then write it like this:
private function clickHandler(event:MouseEvent):void {
var button:Button = event.currentTarget as Button;
if (button && button.enabled) // do things
}
event.target vs event.currentTarget - very-very rarely you would need the event.target, most of the time you need the currentTarget. I'm not saying it is wrong, but, it looks like it might be the problem. target is the object that was the first cause of the event. Events may bubble, which means they may travel the display list hierarchy up and down, first from the parent to child, then in reverse direction. In the example below, suppose there was a label on the button, which was clicked once the event was generated - in such case, even if you added a listener to the button, event.target would be the button label, not the button. currentTarget is, on the contrary, the immediate object which dispatched the event into the handler.
Few more things: ObjectProxy is an idiotic class, you probably shouldn't use at any event. It serves no purpose and, perhaps, buggy, but very few cared to discover its bugs so far. In a nutshell, what it does is as follows: it creates an object, which "watches" dynamic creation, assignment and removal of its properties and dispatches events when these events happen. This behavior is prone to a lot of errors and implicit bugs. For example, is foo.bar = "baz"; foo.bar = "baz"; a reassignment of the same property or not? Is foo.bar.baz = "fizzbuzz"; a modification of foo.bar? What if property name is not a sting? And so on.
Why you shouldn't use it: there is always a better way to treat your data. A more transparent, easier to debug, more efficient. This class is a prototype, which had never really worked. Besides having the behavior described above, it is huge in terms of lines of code that were used to write it. Debugging the errors that happen inside of it requires a lot of time and patience, which are certainly not worth it.
If you need an object to represent a user, define a class, with properties you expect the user to have and just use that class - this will make debugging and understanding your code much easier.
[Bindable] metadata is evil. I can't tell you you should avoid it, because it is used too often, but, I will. You should avoid it as much as possible. I didn't yet encounter an instance of when the use of this meta would be justified. Much in the similar spirit as ObjectProxy it is a prototype, something designed for lazy programmers w/o much consideration for either performance or corner cases. This is, again, a source of a lot of implicit bugs, typically difficult to spot due to the code generated around this meta "swallowing" the errors. The alternative to this meta is plain addEventListener(...) code with custom events.
Unfortunately, a lot of tutorial will use this kind of code to have you quickly started with the language + framework...
** there are some exceptions to this rule: constants are all upper-case and namespace names use underscores to separate the logical part of the word, but never use uppercase letters.
For a game I'm attempting to develop, I am writing a resource pool class in order to recycle objects without calling the "new" operator. I would like to be able to specify the size of the pool, and I would like it to be strongly typed.
Because of these considerations, I think that a Vector would be my best choice. However, as Vector is a final class, I can't extend it. So, I figured I'd use composition instead of inheritance, in this case.
The problem I'm seeing is this - I want to instantiate the class with two arguments: size and class type, and I'm not sure how to pass a type as an argument.
Here's what I tried:
public final class ObjPool
{
private var objects:Vector.<*>;
public function ObjPool(poolsize:uint, type:Class)
{
objects = new Vector.<type>(poolsize); // line 15
}
}
And here's the error I receive from FlashDevelop when I try to build:
\src\ObjPool.as(15): col: 18 Error: Access of undefined property type.
Does anybody know of a way to do this? It looks like the Flash compiler doesn't like to accept variable names within the Vector bracket notation. (I tried changing constructor parameter "type" to String as a test, with no results; I also tried putting a getQualifiedClassName in there, and that didn't work either. Untyping the objects var was fruitless as well.) Additionally, I'm not even sure if type "Class" is the right way to do this - does anybody know?
Thanks!
Edit: For clarification, I am calling my class like this:
var i:ObjPool = new ObjPool(5000, int);
The intention is to specify a size and a type.
Double Edit: For anyone who stumbles upon this question looking for an answer, please research Generics in the Java programming language. As of the time of this writing, they are not implemented in Actionscript 3. Good luck.
I have been trying to do this for a while now and Dominic Tancredi's post made me think that even if you can't go :
objects = new Vector.<classType>(poolsize);
You could go something like :
public final class ObjPool
{
private var objects:Vector.<*>;
public function ObjPool(poolsize:uint, type:Class)
{
var className : String = getQualifiedClassName(type);
var vectorClass : Class = Class(getDefinitionByName("Vector.<" + className + ">"));
objects = new vectorClass(poolsize);
}
}
I tried it with both int and a custom class and it seems to be working fine. Of course you would have to check if you actually gain any speed from this since objects is a Vector.<*> and flash might be making some implicit type checks that would negate the speed up you get from using a vector.
Hope this helps
This is an interesting question (+1!), mostly because I've never tried it before. It seems like from your example it is not possible, which I do find odd, probably something to do with how the compiler works. I question why you would want to do this though. The performance benefit of a Vector over an Array is mostly the result of it being typed, however you are explicitly declaring its type as undefined, which means you've lost the performance gain. So why not just use an array instead? Just food for though.
EDIT
I can confirm this is not possible, its an open bug. See here: http://bugs.adobe.com/jira/browse/ASC-3748 Sorry for the news!
Tyler.
It is good you trying to stay away from new but:
Everything I have ever read about Vector<> in actionscript says it must be strongly typed. So
this shouldn't work.
Edit: I am saying it can't be done.
Here see if this helps.
Is it possible to define a generic type Vector in Actionsctipt 3?
Shot in the dock, but try this:
var classType:Class = getDefinitionByName(type) as Class;
...
objects = new Vector.<classType>(poolsize); // line 15
drops the mic
I don't really see the point in using a Vector.<*>. Might as well go with Array.
Anyhow, I just came up with this way of dynamically create Vectors:
public function getCopy (ofVector:Object):Object
{
var copy:Object = new ofVector.constructor;
// Do whatever you like with the vector as long as you don't need to know the type
return copy;
}