AS3 : AddChild based on Array Value - arrays

Question

Let's say I have an array, each item in the array has a corresponding library item.
I'd like to do something like :
var rando = Math.round(Math.random()*3)
var myArray = new Array ["ball", "wall", "fall"]
var i:myArray[rando] = myArray[rando] new myArray[rando]()
addChild(i)
But, this doesn't work. What's the secret?
Thank You,
Victor Hugo

Answer 1

Surprised no one mentioned getDefinitionByName() here.
Here's some complete code to get your example working:
var myArray = ["ball", "wall", "fall"];
/**
* Creates a random instance based on an input array containing class names as Strings.
* #param The input array containing aforementioned Strings.
* #return The newly created instance.
*/
function createRandom(typeArray:Array):*
{
// Select random String from typeArray.
var selection:String = typeArray[ int(Math.random() * typeArray.length) ];
// Create instance of relevant class.
var Type:Class = getDefinitionByName(selection) as Class;
// Return created instance.
return new Type();
}
// Randomly create and add instance.
var instance:DisplayObject = createRandom(myArray);
addChild(instance);

Answer 2

Ok so there are a bunch of problems with this.
A large one being var i:myArray[rando] = myArray[rando] new myArray[rando]() not really too sure what you're trying to do here.
Anyway I'm going to assume ball, wall and fall are instance names of MovieClips you have in your library. I think you're going to want something like this
var rando:int = Math.floor(Math.random()*3); //As the comments point out this should give you a random
//int between 0 and 2, arrays are 0 indexed so this is what we want if we have 3 items
Now for your array, you're current putting strings in there. Flash has no idea what "ball", etc are.
Try something like this
var myArray:Array = new Array [new ball(), new wall(), new fall()]; //this creates a new instance of your library object and stores it in your array
Now to add one of these to your stage:
addChild(myArray[rando]); //this uses the random number to pull one of the items out of your array
What you're trying to do with var i:myArray[rando] doesn't really make sense. There is no type of myArray[rando] this slot should be holding a MovieClip

Answer 3

If you only have a few choices, it's easier to use a switch-case.
switch (rando) {
case 0:
i = new ball();
break;
case 1:
i = new wall();
break;
case 2:
i = new fall();
break;
}
addChild(i);
I suggest you define the variable i as a MovieClip, in which case it can be instantiated as both ball, wall, fall.
Given that ball, wall and fall are in the library exported to actionscript.

Answer 4

Just guessing off your limited information but give this a shot.
private function myFunction():void{
var rando = Math.round(Math.random()*3);
var myArray= new Array ["ball", "wall", "fall"];
}
private function generateItem(item:String):void{
switch(item){
case "ball" : generateBall(); break;
case "wall" : generateWall(); break;
case "fall" : generateFall(); break;
}
private function generateBall():void{
//code to generate ball
addChild(ball);
}
private function generateFall():void{
//code to generate fall
addChild(fall);
}
private function generateWall():void{
//code to generate wall
addChild(wall);
}

Answer 5

Change your arrary line to:
var myArray = new Array [ball, wall, fall];
This should work. :)

Answer 6

Marty Wallace gets big praise for steering me down the path of getDefinitionByName(). The example he posted was good, but this example does exactly what I was going for.
http://www.emanueleferonato.com/2011/03/31/understanding-as3-getdefinitionbyname-for-all-eval-maniacs/