在Flash中将TextArea设置为只读吗？

TextArea

selectable

package
{
    import flash.text.TextField;
    import flash.display.Bitmap;
    import flash.display.BitmapData;

    public class BitmapText extends Bitmap
    {
        // vars
        private var _textf:TextField;

        /**
         * Draws text onto the bitmap
         * @param tf The TextField to draw
         */
        public function drawText(tf:TextField):void
        {
            _textf = tf;

            bitmapData = new BitmapData(tf.width,tf.height,true);
            bitmapData.draw(tf);
        }

        /**
         * Update text
         * @param t The new text
         */
        public function set text(t:String):void
        {
            if(_textf)
            {
                _textf.text = t;
                drawText(_textf);
            }
        }
    }
}

var t:TextField = new TextField();
t.text = \"some copy\";

var bt:BitmapText = new BitmapText();
bt.drawText(t);

addChild(bt);

bt.text = \"some new text lol\";

BitmapText.text = \"new value\";