Clearing tiles in tile based as3 game - actionscript-3

Question

I been searching for a way to handle this for hours but have found nothing. In my BuildMap function, I instantiate new MovieClips (Tile) with the instance name cell. Their frame is based on my 2d array (protoMap). The problem is that the cells are instantiated in the function. I don't know how to access them outside of it. I want to removeChild(cell) but the only way I know how is within the function that it's instantiated in.
public function BuildMap()
{
for (var i:int=0; i < mapHeight; i++)
{
for (var u:int=0; u < mapWidth; u++)
{
var cell:MovieClip = new Tile();
cell.gotoAndStop(protoMap[i][u]+1);
cell.x = tileSide*u;
cell.y = tileSide*i;
addChild(cell);
var currCellLabel:String = cell.currentFrameLabel;
mapLabels[i].push(currCellLabel);
}
}
}
I want a function called ClearMap() that loops through again and does removeChild(cell). I thought about doing a clearTiles:Boolean and in BuildMap() do
if(clearTiles == false)
{
build the map;
}else{loop again and removeChild(cell)}
but that didn't work... so then I tried to pass cell as an argument to BuildMap() but when I tried to remove it, it wasn't an object of the caller... or something like that. I was also thinking to put cell into its own array, but I don't want to waste memory unnecessarily. Any solutions for the noob?

Answer 1

Create a class instead of using functions.
The point of a class is to isolate concerns.
In your case, you want to deal with all those tiles. (create them according to protoMap and be able to delete them all.
Extending a DisplayObjectContainer such as Sprite, will allow you to add all the tiles to the map object, then you can add and remove the map easily.
Your BuildMap function becomes the constructor.
Here's some non working pseudo code that illustrates the idea:
package
{
public class Map extends Sprite
{
public function Map (data, width, height)
{
for (var i:int=0; i < height; i++)
{
for (var u:int=0; u < width; u++)
{
var cell:MovieClip = new Tile();
cell.gotoAndStop(data[i][u]+1);
cell.x = tileSide*u;
cell.y = tileSide*i;
addChild(cell);
var currCellLabel:String = cell.currentFrameLabel;
mapLabels[i].push(currCellLabel);
}
}
}
public function clear():void
{
removeChildren();
}
}
}
The whole map is contained in that class. You'd have to add the labels, but you didn't specify what they are or what they do, so I left them out.
You can use it like so:
var awesomeMap:Map = new Map(protoMap, mapWidth, mapHeight);
addChild(awesomeMap);
//later
awesomeMap.clear();
//or
removeChild(awesomeMap);
I'd like to point out that building tile maps with MovieClips this way is a bad idea. MovieClips are horrible for performance, because they carry the overhead of their timeline.
Removing all children is very wasteful, too.
So if you have performance problems, try reusing objects and/or employing a technique called "blitting"
See this article: http://www.adobe.com/devnet/flash/articles/blitting_mc.html