actionscript-3 - 如何为页面使用多个框架

Question

我想为我的游戏创建简单的导航。我所做的是在我的 .fla 文件和 in.as 文件的不同帧中创建空影片剪辑，将子级添加到该影片剪辑，但我收到错误Line 24 1061: Call to a possible undefined method addChild through a reference with static type班级。

这是我的 .as 文件代码：

package  {

import flash.display.MovieClip;
import flash.text.TextField;
import flash.text.TextFormat;
import flash.events.Event;

public class KingOfMath extends MovieClip  {
    public function KingOfMath():void  {

        //Create load progress text format
        var loadProgressFormat:TextFormat = new TextFormat();
        loadProgressFormat.align = "center";
        loadProgressFormat.bold = true;
        loadProgressFormat.font = "Arial";
        loadProgressFormat.size = 16;

        //Create load progress text field
        var loadProgressText:TextField = new TextField();
        loadProgressText.defaultTextFormat = loadProgressFormat;
        loadProgressText.width = 550;
        loadProgressText.x = 0;
        loadProgressText.y = 350;
        loadScreen.addChild(loadProgressText);

        //Create progress bar mechanism
        stop();

        addEventListener(Event.ENTER_FRAME, loadProgress);

        function loadProgress(event:Event):void  {
            //Get bytes loaded and bytes total
            var gameBytesLoaded:int = root.loaderInfo.bytesLoaded;
            var gameBytesTotal:int = root.loaderInfo.bytesTotal;

            //Convert to kilobytes
            var gameKilobytesLoaded:int = gameBytesLoaded / 1024;
            var gameKilobytesTotal:int = gameBytesLoaded / 1024;

            //Show progress text
            loadProgressText.text = "Loading: " + gameKilobytesLoaded + "K/" + gameKilobytesTotal + "K";

            if(gameKilobytesLoaded >= gameKilobytesTotal)  {
                removeEventListener(Event.ENTER_FRAME, loadProgress);
                gotoAndStop(2);
            }

        }
    }
}
}