HarmonyOS 缓存无法清理干净

使用FAQ中清理缓存的方法，无法彻底清除缓存：

https://developer.huawei.com/consumer/cn/doc/harmonyos-faqs-V5/faqs-local-file-manager-12-V5

这边创建了一个缓存管理类，按照文档获取和清除app缓存，但是无法彻底清理干净。

import { BusinessError } from '@ohos.base';
import { Logger } from '@ohos/httpclient';
import { fileIo, storageStatistics } from '@kit.CoreFileKit';


//缓存管理工具
export class TBXCacheManager {
  private static instance: TBXCacheManager;
  appCacheSize: number = 0
  private constructor() {
  }

  public static getInstance(): TBXCacheManager {
    if (!TBXCacheManager.instance) {
      TBXCacheManager.instance = new TBXCacheManager()
    }
    return TBXCacheManager.instance;
  }

  /*获取APP缓存打下MB*/
  async getAppCahceSize(): Promise<number> {
    const statistics: storageStatistics.BundleStats = await storageStatistics.getCurrentBundleStats()
    if (statistics) {
      this.appCacheSize = Math.round(statistics.cacheSize/(1024*1024.0) * 10) /10
      console.debug('appCacheSize:',this.appCacheSize)
    }
    return this.appCacheSize
  }

  /*清除APP所有缓存信息*/
  async removeAppAllCache(context: Context) {
    let cacheDir = context.cacheDir;
    console.debug('cacheDic:', cacheDir)
    fileIo.rmdir(cacheDir, (err: BusinessError) => {
      if (err) {
        Logger.debug('remove app cache faild' + err.message)
      } else {
        console.debug('clear success')
        this.getAppCahceSize()
        fileIo.listFile(cacheDir).then((filenames) => {
          console.debug('fileNames:',filenames.length)
          for (let i = 0; i < filenames.length; i++) {
            let dirPath = cacheDir + filenames[i];
            // 判断是否为文件夹
            let isDirectory: boolean = false;
            try {
              isDirectory = fileIo.statSync(dirPath).isDirectory();
            }
            catch (e) {
              console.log(e);
            }

            if (isDirectory) {
              fileIo.rmdirSync(dirPath);
            } else {
              fileIo.unlink(dirPath).then(() => {
                console.info('remove file succeed');
              }).catch((err: Error) => {
                console.info('remove file failed with error message: ' + err.message);
              });
            }
          }
        })
      }
    })
  }
}