HarmonyOS鸿蒙Next中如何将base64字符串转成pdf文件保存到手机并供用户查看

HarmonyOS鸿蒙Next中如何将base64字符串转成pdf文件保存到手机并供用户查看

import { BusinessError, systemDateTime } from "@kit.BasicServicesKit"
import { buffer } from "@kit.ArkTS"
import fs from '@ohos.file.fs';
import { picker } from "@kit.CoreFileKit";

export class FileUtil {
  static async saveBase64Image(fileName: string,base64ImageData: string, context: Context): Promise<Boolean> {
    try {
      let base64Result = FileUtil.dealBase64Str(base64ImageData)
      let file = FileUtil.createFile(context,fileName)
      let bufferImage = buffer.from(base64Result, 'base64')
      await fs.write(file.fd, bufferImage.buffer)
      fs.closeSync(file.fd)

      const documentSaveOptions = new picker.DocumentSaveOptions(); // 创建文件管理器选项实例
      documentSaveOptions.newFileNames = [fileName]; // 保存文件名（可选）
      documentSaveOptions.fileSuffixChoices = ['']; // 保存文件类型（可选）
      let uris: Array<string> = [];
      const documentViewPicker = new picker.DocumentViewPicker(); // 创建文件选择器实例
      documentViewPicker.save(documentSaveOptions).then((documentSaveResult: Array<string>) => {
        uris = documentSaveResult;
        console.info('documentViewPicker.save to file succeed and uris are:' + uris);
        let uri = uris[0];
        let file2 = fs.openSync(uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
        let writeLen2 = fs.writeSync(file2.fd, bufferImage.buffer);
        fs.closeSync(file2);

      }).catch((err: BusinessError) => {
        console.error(`Invoke documentViewPicker.save failed, code is ${err.code}, message is ${err.message}`);
      })

      return Promise.resolve(true)
    } catch (e) {
      throw new Error(e)
    }
  }

  private static dealBase64Str(base64Data: string): string {
    let imageData: string
    if (base64Data.startsWith("data")) {
      const base64Split: string[] = base64Data.split(",")
      if (base64Split.length !== 2) {
        throw new Error(`ImageUtils: Illegal base64 data`)
      }
      imageData = base64Split[1].trim()
    } else {
      imageData = base64Data
    }
    return imageData
  }

  private static createFile(context: Context,fileName: string) {
    let pathDir = context.filesDir
    let filePath = `${pathDir}/${fileName}`
    let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE)
    return file
  }
}