HarmonyOS 如何在页面退出的时候执行回调？

Question

比如想在某个页面打开的时候设置一个回调进去，页面退出的时候调用这个回调来通知调用方，代码如下，但是在aboutToAppear中只能获取到test参数，completionCallback参数永远是undefined。这个原因是什么，如何解决？

private async startFaceAuth(params: AuthCheckParams): Promise<boolean> {
  return new Promise((resolve, reject) => {
    router.pushNamedRoute({
      name: "VerifyFacePager",
      params: {
        test: "asasss",
        completionCallback: (success: boolean) => {
          resolve(success)
        }
      }
    })
  })
}

@Entry({ routeName: "VerifyFacePager" })
@Component
export struct VerifyFacePager {
  @State isAgree: boolean = false
  @State message: string = '发起认证';
  @State certifyID: string = ''
  uid: number = 0
  metaInfo: string = ""
  completionCallback?: (success: boolean) => void

  aboutToAppear(): void {
    const params = router.getParams() as VerifyFacePagerParams
    this.completionCallback = params.completionCallback
    console.log("aboutToAppear", params)
  }
}

Answer 1

router不能传递函数，可以用Emitter 参考文档：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-emitter-V5\#emitteron