how to add a movieclip to second frame of main timeline through document class? - actionscript-3

Question

i simply have one layer which has two frames
frame 1 : menu with only one button
frame 2 : blank but with document class want to put Movie Clip named circle
I want to put it that way because i will program the symbol to draw ....(till now wrote nothing)
In document class till now i have written
package
{
//list of our imports these are classes we need in order to
//run our application.
import flash.display.MovieClip;
import flash.display.Stage;
import flash.events.Event;
public class engine extends MovieClip
{
// moved ourShip to a class variable.
private var ourShip:circle = new circle()
//our constructor function. This runs when an object of
//the class is created
public function engine()
{
ourShip.x = stage.stageWidth / 2;
ourShip.y = stage.stageHeight / 2;
addChild(ourShip)
}
}
}
First frame button as file :
package
{
//imports
import flash.events.MouseEvent;
import flash.display.SimpleButton;
import flash.display.MovieClip;
//-------
public class start extends SimpleButton
{
public function start()
{
addEventListener(MouseEvent.CLICK, onTopClick);
addEventListener(MouseEvent.MOUSE_OVER, onBottomOver);
}
function onTopClick(e:MouseEvent):void
{
MovieClip(root).gotoAndStop(2)
}
function onBottomOver(e:MouseEvent):void
{
}
}
}
By the way i only know addchild (which i wrote in as here,right now it would display circle in both frame 1 and frame 2 but i want it in only frame 2)

Answer 1

Because of how the Flash timeline works, you can only add something to a frame when you are there. So you can do,
goToAndStop(3);
addChild(myClip);
But then if you leave frame 3 it is gone forever.
You can
Add the code to the individual frame of the timeline, or
You can create a simple Event listener like below
Adding Event Listener:
addEventListener(Event.ENTER_FRAME, function() {
if (this.currentFrame == 3) {
addChild(myClip)
}
})