as3.0 选择题2

package com{
    import flash.display.MovieClip;
    import flash.display.SimpleButton;
    import flash.events.MouseEvent;
    import flash.text.TextField;
    import flash.system.fscommand;

    public class FristFrame extends MovieClip {

        private var thisMc:MovieClip;
        private var txtMc:MovieClip;
        private var btnMc:MovieClip;
        public static var answerArr:Array=[];
        private var arr:Array=["A","B","C","D"];

        private var nextBtn:SimpleButton;
        public function FristFrame(_thisMc:MovieClip,_txtMc:MovieClip,_btnMc:MovieClip) {
            thisMc=_thisMc;
            txtMc=_txtMc;
            btnMc=_btnMc;
            btnMc.addEventListener(MouseEvent.CLICK,onBtn);
            for (var i:uint =0; i<txtMc.numChildren; i++) {
                var txt:TextField=txtMc.getChildAt(i) as TextField;
                btnMc.getChildAt(i).alpha=0;
                txt.text="";
            }
            txtMc.addEventListener(MouseEvent.CLICK,onTxt);
        }
        private function onTxt(e:MouseEvent) {
            e.target.text="";
        }
        private function onBtn(e:MouseEvent) {
            for (var i:uint=0; i<btnMc.numChildren; i++) {
                if (e.target.name==btnMc.getChildAt(i).name) {
                    var txt0:TextField;
                    var txt1:TextField;
                    var str:String;
                    var j:uint;
                    if (i%2==0) {
                        str="A";
                        j=i;
                    } else {
                        str="B";
                        j=i-1;
                    }
                    var num:Number=j+2;
                    for (j; j<num; j++) {
                        var txt:TextField=txtMc.getChildAt(j) as TextField;
                        if (txt.text==""&&j!=num) {
                            txt.text=str;
                            return;
                        }
                    }
                }
            }
        }
        public function nextFun(_nextBtn:SimpleButton ) {
            nextBtn=_nextBtn;
            nextBtn.addEventListener(MouseEvent.CLICK,onNextBtn);
        }
        private function onNextBtn(e:MouseEvent) {
            thisMc.nextFrame();
            txtMc.removeEventListener(MouseEvent.CLICK,onTxt);
            nextBtn.removeEventListener(MouseEvent.CLICK,onNextBtn);
            for (var i:uint =0; i<txtMc.numChildren; i++) {
                var txt:TextField=txtMc.getChildAt(i) as TextField;
                answerArr.push(txt.text);
            }
        }
    }

}