沙箱路径的文件怎么拿取？

import buffer from 'hos.buffe'; 
import fs from '@ohos.file.fs'; 
import picker from '@ohos.file.picker'; 
import { BusinessError } from'@ohos.base’; 
 
@Entry 
@Component 
struct Index { 
  @State imageBuffer: ArrayBuffer = new ArrayBuffer(96) 
  @State audioUrl: string = “” 
  @State audioSaveResult: string = “” 
  build() { 
    Row() { 
      Column() { 
Text(“写文件”) 
.onClick(() => { 
// 写入 
}) 
 
    Text("pcmPickerSave") 
      .fontSize(30) 
      .fontWeight(FontWeight.Bold) 
      .onClick(async () => { 
        const audioSaveOptions = new picker.AudioSaveOptions(); // 创建文件管理器选项实例 
        audioSaveOptions.newFileNames = ['AudioViewPicker.pcm']; // 保存文件名（可选） 
        const audioViewPicker = new picker.AudioViewPicker(); 
        audioViewPicker.save(audioSaveOptions).then((audioSelectResult: Array<string>) => { 
          this.audioSaveResult = audioSelectResult[0]; 
          console.info('audioViewPicker.save to file succeed and uri is:' + this.audioSaveResult); 
        }).catch((err: BusinessError) => { 
          console.error(`Invoke audioViewPicker.save failed, code is ${err.code}, message is ${err.message}`); 
        }) 
      }) 
 
    Text("pcmSave") 
      .fontSize(30) 
      .fontWeight(FontWeight.Bold) 
      .onClick(async () => { 
        try { 
          this.imageBuffer = buffer.from("hello word").buffer 
          //使用读取的buffet保存 
          let file2 = fs.openSync(this.audioSaveResult, fs.OpenMode.READ_WRITE); 
          let writeLen = await fs.write(file2.fd, this.imageBuffer); 
          fs.closeSync(file2); 
          console.info("msgXucan [picker] writeOnly writeLen = " + writeLen); 
          AlertDialog.show({ message: '已保存至本地!' }); 
        } catch (error) { 
          let err: BusinessError = error as BusinessError; 
          console.info("[picker] writeOnly error: " + JSON.stringify(err)); 
        } 
      }) 
  }.width('100%') 
      .height('100%') 
    } 
    .height(‘100%’) 
  } 
}