[]怎么对graphics画出来的图片进行鼠标点击拖动？？？

我把示例的内容进行了修改，我不想加载个图片然后移动图片，我只是想画个圆圈然后鼠标可以拖动它移动！！！！但是我改了一下官网上的例子，还是无法移动。。。。。官网例子的地址：https://layaair.ldc.layabox.com/demo/?2d&Interaction&Drag 
 
不得不吐槽一下，你们layabox的官方教程简直太简略，而且社区里的很多回答也是简略至极，这一点layabox远远不如白鹭。。。。

我改的代码如下：

module laya {

import Sprite = Laya.Sprite;
import Stage = Laya.Stage;
import Event = Laya.Event;
import Rectangle = Laya.Rectangle;
import Texture = Laya.Texture;
import Browser = Laya.Browser;
import Handler = Laya.Handler;
import WebGL = Laya.WebGL;

export class Interaction_Drag {
private ApePath: string = "../laya/monkey2.png";

private ape: Sprite;
private dragRegion: Rectangle;

constructor() {
// 不支持WebGL时自动切换至Canvas
Laya.init(Browser.clientWidth, Browser.clientHeight, WebGL);

Laya.stage.alignV = Stage.ALIGN_MIDDLE;
Laya.stage.alignH = Stage.ALIGN_CENTER;

Laya.stage.scaleMode = "showall";
Laya.stage.bgColor = "#232628";

//这里是我注释掉的代码
//Laya.loader.load(this.ApePath, Handler.create(this, this.setup));
this.setup();
}

private setup(): void {
this.createApe();
this.showDragRegion();
}

private createApe(): void {
this.ape = new Sprite();

//this.ape.loadImage(this.ApePath);
Laya.stage.addChild(this.ape);

//这里是我注释掉的代码
//var texture: Texture = Laya.loader.getRes(this.ApePath);
//this.ape.pivot(texture.width / 2, texture.height / 2);
this.ape.x = Laya.stage.width / 2;
this.ape.y = Laya.stage.height / 2;

//这里是我加的代码
this.ape.graphics.drawCircle(50, 50, 30, "#ff0000");

this.ape.on(Event.MOUSE_DOWN, this, this.onStartDrag);
}

private showDragRegion(): void {
//拖动限制区域
var dragWidthLimit: number = 350;
var dragHeightLimit: number = 200;
this.dragRegion = new Rectangle(Laya.stage.width - dragWidthLimit >> 1, Laya.stage.height - dragHeightLimit >> 1, dragWidthLimit, dragHeightLimit);

//画出拖动限制区域
Laya.stage.graphics.drawRect(
this.dragRegion.x, this.dragRegion.y, this.dragRegion.width, this.dragRegion.height,
null, "#FFFFFF", 2);
}

private onStartDrag(e: Event): void {
//鼠标按下开始拖拽(设置了拖动区域和超界弹回的滑动效果)
this.ape.startDrag(this.dragRegion, true, 100);
}
}
}
new laya.Interaction_Drag();