Action script 3 question: addChild and removeChild on same button??

Question

I'm trying to make a button that when u click once, the movieclip will be removed and second time back on stage and so forth....
somehow i get this error
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ArgumentError: Error #2025: The supplied DisplayObject must be a child of the caller.
at flash.display:DisplayObjectContainer/removeChild()
at sample_fla::MainTimeline/btnClick()
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Anyone can help me with this, since I'm doing an interactive web for client and the deadline is near..... thanks in advance.
these are my code:
stop();
var swf:MovieClip;
var loader:Loader= new Loader();
var defaultswf:URLRequest= new URLRequest("./newSwfImport.swf");
//default swf when loaded
loader.load(defaultswf);
//add to stage
allSwfLoadHere.addChild(loader);
var boolean:Boolean = true ;
function btnClick(event:MouseEvent):void {
if(boolean == true){
allSwfLoadHere.removeChild(loader);
boolean == false
if(boolean ==false){
allSwfLoadHere.addChild(loader);
boolean == true
newSwfImport.addEventListener(MouseEvent.CLICK,btnClick);

Answer 1

you have, at least, two errors:
1.  you failed to use an if-else and
2.  when trying to re-assign your boolean, you tested.  ie, you used == when you should use =.  so, your boolean remains true.  then when you execute the 2nd time, you try and remove something that's already been removed.
use:
var swf:MovieClip;
var loader:Loader= new Loader();
var defaultswf:URLRequest= new URLRequest("./newSwfImport.swf");
//default swf when loaded
loader.load(defaultswf);
//add to stage
allSwfLoadHere.addChild(loader);
var boolean:Boolean = true ;
function btnClick(event:MouseEvent):void {
if(boolean){
allSwfLoadHere.removeChild(loader);
} else {
allSwfLoadHere.addChild(loader);
boolean=!boolean;
newSwfImport.addEventListener(MouseEvent.CLICK,btnClick);