HarmonyOS 如何实现获取用户头像保存到系统相册

import { http } from '@kit.NetworkKit' 
import { BusinessError } from '@kit.BasicServicesKit'; 
import ResponseCode from '@ohos.net.http'; 
import { photoAccessHelper } from '@kit.MediaLibraryKit'; 
import fs from '@ohos.file.fs'; 
 
@Entry 
@Component 
struct Index { 
  loadImageWithUrl(url: string) { 
    // 使用request下载图片并在回调函数中保存图片到相册 
    http.createHttp().request(url, 
      { 
        method:http.RequestMethod.GET, 
        connectTimeout:60000, 
        readTimeout:60000 
      }, 
      async (error: BusinessError, data: http.HttpResponse) => { 
        if (error) { 
          console.error(`http reqeust failed with. Code: ${error.code}, message: ${error.message}`); 
        } else { 
          if (ResponseCode.ResponseCode.OK === data.responseCode) { 
            let imageBuffer: ArrayBuffer = data.result as ArrayBuffer; 
            try { 
              // 获取相册路径 
              const context = getContext(this); 
              let helper = photoAccessHelper.getPhotoAccessHelper(context); 
              let uri = await helper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg') 
              let file = await fs.open(uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE) 
              // 写入文件 
              await fs.write(file.fd, imageBuffer); 
              // 关闭文件 
              await fs.close(file.fd); 
            } catch (error) { 
              console.error("error is "+ JSON.stringify(error)) 
            } 
          } else { 
            console.error("error occurred when image downloaded!") 
          } 
        } 
      }) 
  } 
  ...... 
}

let context: Context = getContext(this); 
// 获取待保存图像的ArrayBuffer 
const resourceMgr: resourceManager.ResourceManager = context.resourceManager; 
const fileData: Uint8Array = await resourceMgr.getRawFileContent('beer.jpeg'); 
const buffer = fileData.buffer; 
 
// 获取相册的保存路径 
let helper = photoAccessHelper.getPhotoAccessHelper(context); 
let uri = await helper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpeg'); 
let file = await fs.open(uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE); 
 
// 写入文件并关闭文件流 
await fs.write(file.fd, buffer); 
await fs.close(file.fd);