[]2.0 beta UI Button无法获取

import View=Laya.View;

import Dialog=Laya.Dialog;

import Scene=Laya.Scene;

export module ui {

    export class AttackUI extends View {

		public btn_attack:Laya.Button;

        constructor(){ super()}

        createChildren():void {

            super.createChildren();

            this.loadScene("Attack");

        }

    }

}

import { ui } from "../ui/layaMaxUI";



export default class AttackView extends ui.AttackUI {

    constructor() {

        super();



        this.btn_attack.on("click", this, this.onAttack);

    }



    private onAttack(): void {

        // TODO

    }

}