如何在as3类中控制动画的播放？

首先，建一个MC，做好一段动画，
然后，写一个类：MyMovie
package
{
import flash.events.MouseEvent;
import flash.display.MovieClip;
import flash.display.Sprite;
import flash.text.TextField;

/**
* ...
* @author keys.star@gamil.com
*/
public class MyMovie extends MovieClip
{
public function MyMovie():void {
stop()//开始停止
addFrameScript(1, frame2);//加入第二桢中的代码
createBt();//创建一个按钮测试
}
private function createBt():void {
var sp:Sprite = new Sprite;
sp.buttonMode = true;
sp.graphics.beginFill(0);
sp.graphics.drawRect(100, 100, 50, 30);
sp.graphics.endFill();
sp.addEventListener(MouseEvent.CLICK, goto)
addChild(sp);
}
private function goto(e:MouseEvent):void {
gotoAndStop(2);
}
private function frame2():void {
var txt:TextField = new TextField;
txt.text = "这是第二桢";