HarmonyOS在元服务里面怎么打开相机拍照到指定目录

import picker from '@kit.CameraKit'; 
class CameraPosition { 
  cameraPosition : camera.CameraPosition 
  saveUri :string 
  constructor(cameraPosition : camera.CameraPosition, saveUri:string) { 
    this.cameraPosition = cameraPosition 
    this.saveUri = saveUri 
  } 
} 
let pathDir = getContext().filesDir; 
let filePath = pathDir + '/test.jpg' 
let uri = 'file://包名信息' + filePath 
let pickerProfile = new CameraPosition(camera.CameraPosition.CAMERA_POSITION_BACK, uri) 
//前置摄像机传CAMERA_POSITION_FRONT，后置摄像机传CAMERA_POSITION_BACK，saveuri传想存到对应沙箱的uri 
let pickerResult: picker.PickerResult = await picker.pick(mContext, 
  [picker.PickerMediaType.PHOTO, picker.PickerMediaType.VIDEO], pickerProfile);