AddChild() vs addChildAt() methods?

Question

I have the following code:
var container_mc:Container = new Container();
for (var i:int=0;i<4;i++){
var myTrap_mc:MyTrap = new MyTrap();
var myTrapR_mc:MyTrapR = new MyTrapR();
container_mc.addChildAt(myTrap_mc,i);
container_mc.addChildAt(myTrapR_mc,i);
myTrap_mc.rotate=i*90;
myTrapR_mc.rotate=i*90;
container_mc.x=20;
container_mc.y=20;
trace(myTrap_mc.rotate);
trace(container_mc.x+" x");
MyTrap and MyTrapR are sheared rectangles in my Library with Export at Frame 1 selected.  When I test the movie I don't see any objects on the stage.
If I simply declare addChild(myTrap_mc) within the loop it will add one child instead of 4 which is why I tried using a container and adding the children to the container.  Still no beans.
How can I get these sheared rectangles to appear so that they form an 8-pointed star?  This is simply an exercise in drawing shapes dynamically using ActionScript.  (Of course I'm not using ActionScript graphics properties so it's not truly dynamic in that sense).

Answer 1

Well, the container was always superfluous. Your original problem was with the property rotate vs rotation.
But anyway, in authortime in the Flash program you can create a symbol on the stage, give it an instance name say square_mc. Then add that instance to another symbol with an instance name say container_mc. Then to talk to the inside symbol (square_mc) you call it with dot syntax like so: container_mc.square_mc.
Creating the symbol dynamically changes things. Giving a dynamically created object a name using the name property is different than giving an object an instance name using the property panel. Try changing the name incode of a symbol that you named with the property panel, it can't be done. You can't even assign a name to an object that you placed on the stage even if you didn't name it in the first place.
There is never a need to declare a symbol that you have placed inside another symbol in Flash authortime. In fact, I am not even sure how you could do it. Neither var container_mc.contained_mc:MovieClip nor container_mc.var contained_mc:MovieClip work. I played around with some stuff here:
import flash.display.Sprite;
import flash.display.MovieClip;
var mySquare:Square = new Square; //Square is a movieclip in my fla library
var myContainer:MovieClip = new MovieClip; //a dynamically created movieclip
addChild(myContainer); //put the new movieclip on the stage
mySquare.name = "mySquare_mc"; //give the dynamically instance Square an instance name
myContainer.addChild(mySquare); //add it to the container
trace(mySquare.name); //mySquare_mc
trace(myContainer.getChildByName("mySquare_mc")); //[object Square] BTW referencing the object using this method is less efficient than just calling it mySquare
trace(myContainer.mySquare_mc); //undefined. If container is declared as a Sprite instead of a MovieClip, this gives an undefined property error. Truthfully, I am unsure why this doesn't work (at least when the container is a MovieClip). If you put the square inside the container in Flash at authortime with an instance name it works fine. Or even if you add the container dynamically, if it contained a named symbol in the library it still works. There must be some difference between assigning the name property in code and doing it via the property panel.
var mySquareReference2:MovieClip = MovieClip(myContainer.getChildByName("mySquare_mc")); //assign a new reference in memory to mySquare using the dynamically assigned name "mySquare_mc"
trace(mySquareReference2); //[object Square] BTW, mySquareReference2 is the exact same Square as mySquare, just using a different reference