actionscript 3 - Finding out when Recursion involving Asynchronous operation finishes -

i have recursive call includes asyn operation (file copy) ..
want find out when recursive call finishes (along asyn operations).

    private function copyinto(directorytocopy:file, locationcopyingto:file):void         {           var directory:array = directorytocopy.getdirectorylisting();           //get list of files in dir             each (var f:file in directory)           {             if (f.isdirectory)               copyinto(f, locationcopyingto.resolvepath(f.name));             else              {                f.copytoasyn(locationcopyingto.resolvepath(f.name), true);                f.addeventlistener(event.complete, onfilecopied);               }           }             }  function onfilecopied(event){      alert(event.target); // [object file]  }  

basically needed copy folder structure drive,and folder being copied contains files 100-200mb , take time copy,which blanks out ui , flash player.
, after files copied, want further things(hopefully without blocking ui).

any help?

thanks .

count calls of copytoasync , use wrapper function docopy in example.

private var copycount: int = 0; private var iscopying: boolean = false;  public function docopy(directorytocopy:file, locationcopyingto:file):void {     iscopying = true;     try {       copyinto((directorytocopy, locationcopyingto);     {       iscopying = false;     }  }  private function copyinto(directorytocopy:file, locationcopyingto:file):void {     var directory:array = directorytocopy.getdirectorylisting();      each (var f:file in directory) {         if (f.isdirectory)             copyinto(f, locationcopyingto.resolvepath(f.name));         else {             copycount++;              f.addeventlistener(event.complete, onfilecopied);             f.copytoasync(locationcopyingto.resolvepath(f.name), true);         }     }     }  function onfilecopied(event: event): void {      copycount--;     if (copycount == 0 && !iscopying)         trace("finished"); }  

important: iscopying flag checks if copyinto function still running, otherwise run condition copycount == 0, copying not finished.