访问鸿蒙设备文件 原创

'file://docs/storage/Users/currentUser/<relative_path>/test.txt'

import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { dataSharePredicates } from '@kit.ArkData';

// 定义一个uri数组，用于接收PhotoViewPicker选择图片返回的uri
let uris: Array<string> = [];
const context = getContext(this);

// 调用PhotoViewPicker.select选择图片
async function photoPickerGetUri() {
  try {  
    let PhotoSelectOptions = new photoAccessHelper.PhotoSelectOptions();
    PhotoSelectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.IMAGE_TYPE;
    PhotoSelectOptions.maxSelectNumber = 1;
    let photoPicker = new photoAccessHelper.PhotoViewPicker();
    photoPicker.select(PhotoSelectOptions).then((PhotoSelectResult: photoAccessHelper.PhotoSelectResult) => {
      console.info('PhotoViewPicker.select successfully, PhotoSelectResult uri: ' + JSON.stringify(PhotoSelectResult));
      uris = PhotoSelectResult.photoUris;
    }).catch((err: BusinessError) => {
      console.error('PhotoViewPicker.select failed with err: ' + JSON.stringify(err));
    });
  } catch (error) {
    let err: BusinessError = error as BusinessError;
    console.error('PhotoViewPicker failed with err: ' + JSON.stringify(err));
  }
}

async function uriGetAssets() {
try {
    let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
    let predicates: dataSharePredicates.DataSharePredicates = new dataSharePredicates.DataSharePredicates();
    // 配置查询条件，使用PhotoViewPicker选择图片返回的uri进行查询
    predicates.equalTo('uri', uris[0]);
    let fetchOption: photoAccessHelper.FetchOptions = {
      fetchColumns: [photoAccessHelper.PhotoKeys.WIDTH, photoAccessHelper.PhotoKeys.HEIGHT, photoAccessHelper.PhotoKeys.TITLE, photoAccessHelper.PhotoKeys.DURATION],
      predicates: predicates
    };
    let fetchResult: photoAccessHelper.FetchResult<photoAccessHelper.PhotoAsset> = await phAccessHelper.getAssets(fetchOption);
    // 得到uri对应的PhotoAsset对象，读取文件的部分信息
    const asset: photoAccessHelper.PhotoAsset = await fetchResult.getFirstObject();
    console.info('asset displayName: ', asset.displayName);
    console.info('asset uri: ', asset.uri);
    console.info('asset photoType: ', asset.photoType);
    console.info('asset width: ', asset.get(photoAccessHelper.PhotoKeys.WIDTH));
    console.info('asset height: ', asset.get(photoAccessHelper.PhotoKeys.HEIGHT));
    console.info('asset title: ' + asset.get(photoAccessHelper.PhotoKeys.TITLE));
    // 获取缩略图
    asset.getThumbnail((err, pixelMap) => {
      if (err === undefined) {
        console.info('getThumbnail successful ' + JSON.stringify(pixelMap));
      } else {
        console.error(`getThumbnail fail with error: ${err.code}, ${err.message}`);
      }
    });
  } catch (error){
    console.error('uriGetAssets failed with err: ' + JSON.stringify(error));
  }
}