HarmonyOS 鸿蒙Next 保存base64图片到相册

import { common } from '@kit.AbilityKit';
import { fileIo, fileUri } from '@kit.CoreFileKit';
import { buffer } from '@kit.ArkTS';
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { promptAction, window } from '@kit.ArkUI';
import { BusinessError } from '@kit.BasicServicesKit';
import fs from '@ohos.file.fs';
import { image } from '@kit.ImageKit';

@Entry
@Component
struct photo_240912161900073 {
  @State Base64: string = ''

  async pixelToBase64(pixelMap: PixelMap) {
    // 转换成base64
    const imagePackerApi: image.ImagePacker = image.createImagePacker();
    let packOpts: image.PackingOption = { format: 'image/jpeg', quality: 100 };
    const data = await imagePackerApi.packing(pixelMap, packOpts);
    let buf: buffer.Buffer = buffer.from(data);
    return 'data:image/jpeg;base64,' + buf.toString('base64', 0, buf.length);

  }

  writeFile(data: string): string {
    let context = getContext(this) as common.UIAbilityContext;
    let filesDir = context.filesDir;
    let uri = ''
    try {
      let filePath = filesDir + "/1.jpg";
      uri = fileUri.getUriFromPath(filePath);
      let file = fileIo.openSync(filePath, fileIo.OpenMode.READ_WRITE | fileIo.OpenMode.CREATE);
      console.info("file fd: " + file.fd);
      const reg = new RegExp("data:image/\\w+;base64,")
      const base64 = data.replace(reg, "");
      console.log("base64flag", base64)
      const dataBuffer = buffer.from(base64, 'base64')
      let writeLen = fileIo.writeSync(file.fd, dataBuffer.buffer);
      fileIo.closeSync(file);
    }
    catch (Error) {}
    return uri
  }

  async SavePicture() {
    try {
      let context = getContext(this) as common.UIAbilityContext;
      let windowClass: window.Window | undefined = undefined;
      window.getLastWindow(context, async (err: BusinessError, data) => {
        windowClass = data;
        let pixelMap = await windowClass.snapshot();
        this.Base64 = await this.pixelToBase64(pixelMap);
        this.Base64 = '*******';

        let uri = this.writeFile(this.Base64)
        console.log("保存的路径"+uri)
        let srcFileUris: Array<string> = [
        // 获取需要保存到媒体库的位于应用沙箱的图片/视频uri
          uri
        ];
        let photoCreationConfigs: Array<photoAccessHelper.PhotoCreationConfig> = [
          {
            title: '1',
            fileNameExtension: 'jpg',
            photoType: photoAccessHelper.PhotoType.IMAGE,
            subtype: photoAccessHelper.PhotoSubtype.DEFAULT, // 可选
          }
        ];
        let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
        let desFileUris: Array<string> = await phAccessHelper.showAssetsCreationDialog(srcFileUris, photoCreationConfigs);
        console.info('showAssetsCreationDialog success, data is ' + desFileUris);

        try {
          // 通过uri打开媒体库文件
          if (desFileUris.length>0) {
            console.log("desFileUris[0]:"+desFileUris.length)

            //获取图片的base64字符串
            let imageStr = '******'.split(',');
            //打开文件
            let file = fs.openSync(desFileUris[0], fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
            //base64字符串转成
            const decodeBuffer = buffer.from(imageStr.toString(), 'base64').buffer;
            //写入文件
            fs.writeSync(file.fd, decodeBuffer);
            fs.closeSync(file.fd);
            promptAction.showToast({ message: '已保存至相册！' })
          }else {
            promptAction.showToast({ message: '拒绝！' })
          }

        } catch (err) {
          console.info(err)
          promptAction.showToast({ message: '保存失败！' })
        }


      })
    } catch (err) {
      console.error('showAssetsCreationDialog failed, errCode is ' + err.code + ', errMsg is ' + err.message);
    }
  }

  build() {
    RelativeContainer() {
      Column(){
        Button('保存图片')
          .margin(10)
          .onClick(() => {
            this.SavePicture()
          })
      }
    }
    .height('100%')
    .width('100%')
  }
}