HarmonyOS 鸿蒙Next中选择系统相册里的图片并转base64

可以参考这个从图库选择图片上传案例：

import { BusinessError } from '@ohos.base';
import { rcp } from '@kit.RemoteCommunicationKit';
import { picker } from '@kit.CoreFileKit';
import fs from '@ohos.file.fs';
import { http } from '@kit.NetworkKit';

let uploadUrl: string = '';

function example01(): string {
  let uri = '';
  let photoViewPicker = new picker.PhotoViewPicker();
  let photoSelectOption = new picker.PhotoSelectOptions();
  photoSelectOption.MIMEType = picker.PhotoViewMIMETypes.IMAGE_TYPE;
  photoViewPicker.select(photoSelectOption).then((photoSelectResult) => {
    console.log("fyh photoSelectResult:" + photoSelectResult);
    uri = photoSelectResult.photoUris[0];
    console.log("fyh uri:" + uri);
    try {
      let resultPhoto = fs.openSync(uri, fs.OpenMode.READ_ONLY);
      let resultName = resultPhoto.name;
      let fileTemp = fs.openSync(getContext().filesDir + resultPhoto.name, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
      let imageUri = fileTemp.path;
      fs.copyFileSync(resultPhoto.fd, fileTemp.fd);
      fs.closeSync(resultPhoto);
      fs.closeSync(fileTemp);
      const httpRequest = http.createHttp();
      httpRequest.request(uploadUrl, {
        method: http.RequestMethod.POST,
        header: {
          'Content-Type': 'multipart/form-data',
          'Connection': 'keep-alive'
        },
        expectDataType: http.HttpDataType.ARRAY_BUFFER,
        multiFormDataList: [
          {
            name: 'file',
            contentType: 'image/jpg',
            filePath: imageUri,
            remoteFileName: 'file.jpg'
          },
        ],
      }, (err, data) => {
        console.log('fyh:上传结束')
        httpRequest.destroy();
      }
      )
    } catch (err) {
      console.error(`fyh:Failed to request the upload. err: ${JSON.stringify(err)}`);
    }
  }).catch((err: BusinessError) => {
    console.error(`Invoke photoViewPicker.select failed, code is ${err.code}, message is ${err.message}`);
  })
  return uri;
}

function testRcpMultiPartUpload() {
  example01();
}

function clickget() {
  const session = rcp.createSession();
  session.get("").then((response) => {
    console.log("fyh" + JSON.stringify(response));
  }).catch((err: BusinessError) => {
    console.error("err:" + JSON.stringify(err));
  });
}

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {
            testRcpMultiPartUpload();
          })
        Text('getText')
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {
            clickget();
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}

参考如下demo:

import photoAccessHelper from '@ohos.file.photoAccessHelper';
import image from '@ohos.multimedia.image';
import fs from '@ohos.file.fs';
import { buffer } from '@kit.ArkTS';

@Entry
@Component
struct Page2 {
  @State resultBase64Str: string = '';
  @State getAlbum: string = '显示相册中的图片';
  @State pixel: image.PixelMap | undefined = undefined;
  @State albumPath: string = '';
  @State photoSize: number = 0;

  async getPictureFromAlbum() {
    // 拉起相册，选择图片
    let PhotoSelectOptions = new photoAccessHelper.PhotoSelectOptions();
    PhotoSelectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.IMAGE_TYPE;
    PhotoSelectOptions.maxSelectNumber = 1;
    let photoPicker = new photoAccessHelper.PhotoViewPicker();
    let photoSelectResult: photoAccessHelper.PhotoSelectResult = await photoPicker.select(PhotoSelectOptions);
    this.albumPath = photoSelectResult.photoUris[0];
    console.info('albumPath: ' + this.albumPath)
    // 读取图片为buffer
    const file = fs.openSync(this.albumPath, fs.OpenMode.READ_WRITE);
    this.photoSize = fs.statSync(file.fd).size;
    console.info('Photo Size: ' + this.photoSize);
    let buffer1 = new ArrayBuffer(this.photoSize);
    fs.readSync(file.fd, buffer1);
    let base64Str: string = buffer.from(buffer1).toString('base64')
    let resultBase64Str = "data:image/png;base64," + base64Str
    this.resultBase64Str = resultBase64Str
    fs.closeSync(file);
    // 解码成PixelMap
    const imageSource = image.createImageSource(buffer1);
    console.log('imageSource: ' + JSON.stringify(imageSource));
    this.pixel = await imageSource.createPixelMap({});
  }

  build() {
    Scroll() {
      Column() {
        Text('获取图片')
          .onClick(async () => {
            await this.getPictureFromAlbum()
          })
        // Image(this.pixel)
        Image(this.resultBase64Str).width(40).height(40)
        Text(this.resultBase64Str)
      }
    }
  }
}