HarmonyOS 鸿蒙Next 父组件如何调用子组件内部方法

看下如下代码是否可行：

@Component
struct Child {
  @State private text: string = '初始值'
  @State widthSize: number = 250
  @State heightSize: number = 100
  @State rotateAngle: number = 0
  @State flag: boolean = true
  private controller: ChildController = new ChildController();

  aboutToAppear() {
    if(this.controller) {
      //给controller对应的方法赋值
      this.controller.changeStatus = this.changeStatus
    }
  }

  //封装的能力
  private changeStatus = () =>{
    if (this.flag) {
      this.widthSize = 150
      this.heightSize = 60
    } else {
      this.widthSize = 250
      this.heightSize = 100
    }
    this.flag = !this.flag
  }

  build() {
    Column() {
      Button('change size')
        .onClick(() => {

        })
        .margin(30)
        .width(this.widthSize)
        .height(this.heightSize)
        .animation({
          duration: 2000,
          curve: Curve.EaseOut,
          iterations: 3,
          playMode: PlayMode.Normal
        })

    }.width('100%').margin({ top: 20 })
  }
}

//定义controller对象
class ChildController {
  changeStatus = () => {}
}

@Component
struct Parent {
  private ChildRef = new ChildController()
  private ChildRef1 = new ChildController()
  build() {
    Column() {
      Text('调用Child的changeStatus').fontSize('18vp').fontColor(Color.Gray)
      Divider()
      Child({ controller:this.ChildRef })
      Button('Parent调用childer的changeStatus').onClick(() => {
        this.ChildRef.changeStatus()
      })
      Child({ controller:this.ChildRef1 })
      Button('Parent调用childer的changeStatus').onClick(() => {
        this.ChildRef1.changeStatus()
      })
    }
    .justifyContent(FlexAlign.Center)
    .width("100%")
    .height("100%")
  }
}