HarmonyOS 鸿蒙Next怎样下载文件

import { BusinessError, request } from '[@kit](/user/kit).BasicServicesKit';

import { JSON } from '[@kit](/user/kit).ArkTS';

import { data } from '[@kit](/user/kit).TelephonyKit';

class calssA {

  receivedSize: number

  totalSize: number

  constructor(receivedSize: number, totalSize: number) {

    this.totalSize = totalSize

    this.receivedSize = receivedSize

  }

}

[@Entry](/user/Entry)

[@Component](/user/Component)

struct Index {

  [@State](/user/State) message: string = 'Hello World';

  [@State](/user/State) urlList: string[] = [

    "下载连接",

    "下载连接"

  ]

  [@State](/user/State) downArr: Array<calssA> = []

  build() {

    Column() {

      Button('开始下载').onClick((event: ClickEvent) => {

        this.urlList.forEach((data: string, index: number) => {

          try {

            request.downloadFile(getContext(), { url: data }).then((data: request.DownloadTask) => {

              let downloadTask: request.DownloadTask = data;

              let progressCallback = (receivedSize: number, totalSize: number) => {

                this.downArr[index] = new calssA(receivedSize, totalSize)

              };

              downloadTask.on('progress', progressCallback);

            }).catch((err: BusinessError) => {

              console.error(`Failed to request the download. Code: ${err.code}, message: ${err.message}`);

            })

          } catch (err) {

            console.error(`Failed to request the download. err: ${JSON.stringify(err)}`);

          }

        })

      })

      Text('下载进度')

      ForEach(this.downArr, (data: calssA) => {

        Progress({ value: data.receivedSize / data.totalSize * 100, total: 100 })

          .height(30)

          .margin({ top: 30 })

          .width('100%')

      }, (data: calssA) => JSON.stringify(data))

    }

  }

}