HarmonyOS 如何拿到图片的大小等信息？

Question

import common from '@ohos.app.ability.common';
import picker from '@ohos.file.picker';

@Entry
@Component
struct pickerDemo {
  @State getImg: string = '获取图片'
  @State imgArr: string[] = []

  getPhotoImg() {
    let photoPicker = new picker.PhotoViewPicker();
    photoPicker.select({
      MIMEType: picker.PhotoViewMIMETypes.IMAGE_TYPE,
      maxSelectNumber: 3
    }, (err, data) => {
      if (err) {
        console.info("photoPicker:" + err.message)
        return
      }
      this.imgArr = data.photoUris
      console.log("photoPicker:" + JSON.stringify(data))
      data.isOriginalPhoto
    })
  }

  build() {
    Column() {
      ForEach(this.imgArr, (item: string, index: number) => {
        Row() {
          Image(item).width(100).height(100).borderWidth(1)
        }
      })

      Button(this.getImg).margin(20)
        .onClick(() => {
          this.getPhotoImg()
        })
    }
    .width('100%')
    .height('100%')
    .justifyContent(FlexAlign.Center)
  }
}

Answer 1

可以通过PhotoKeys获取文件信息，参考文档：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-photoaccesshelper-V5\#ZH-CN\_TOPIC\_0000001930677569\_\_photokeys

import picker from '@ohos.file.picker';
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import dataSharePredicates from '@ohos.data.dataSharePredicates';

let uris: Array<string> = [];
const context = getContext(this);

@Entry
@Component
struct Index {
  async photoPick() {
    let PhotoSelectOptions = new picker.PhotoSelectOptions();
    PhotoSelectOptions.MIMEType = picker.PhotoViewMIMETypes.IMAGE_TYPE;
    PhotoSelectOptions.maxSelectNumber = 5;
    let photoPicker = new picker.PhotoViewPicker();
    photoPicker.select(PhotoSelectOptions)
      .then(async (PhotoSelectResult: picker.PhotoSelectResult) => {
        console.info('PhotoViewPicker.select successfully, PhotoSelectResult uri: ' +
        JSON.stringify(PhotoSelectResult));
        uris = PhotoSelectResult.photoUris;
        //调用getAssets接口获取ri对应的PhotoAsset对象，然后通过获取的对象使用PhotoKeys.SIZE获取文件大小
        this.uriGetAssets()
      });
  }

  async 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: [],
        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 size: ', asset.get(photoAccessHelper.PhotoKeys.SIZE));
    } catch (error) {
      console.error('uriGetAssets failed with err: ' + JSON.stringify(error));
    }
  }

  build() {
    Column() {
      Button("选取图片并获取图片大小").onClick(async () => this.photoPick())
    }
  }
}