kotlin 向上轉型問題

       animator.duration = HalfAnimationDuration
       animator.addUpdateListener {
           var message_width:Int = it.getAnimatedValue() as Int
           var lp = this.layoutParams
           lp.width = message_width
           lp.height = message_view.height
           message_view.layoutParams = lp
           lp.height = this.height
           this.layoutParams = lp
       }
       animator.start()
       ```
       記錄一下不知道怎麼向上轉型，這樣會清掉原來的屬性，位置會回到左上