先看OC获取文件大小，清除缓存，删除沙盒里文件的代码

 // 显示缓存大小
+ (float)cacheSize {
  NSString *cachPath = [NSSearchPathForDirectoriesInDomains (NSCachesDirectory, NSUserDomainMask, YES) firstObject];
  return [self folderSizeAtPath:cachPath];
}
//计算一下单个文件的大小
+ (long long)fileSizeAtPath:(NSString *)filePath {
  NSFileManager * manager = [ NSFileManager defaultManager ];
  if ([manager fileExistsAtPath :filePath]){
    return [[manager attributesOfItemAtPath :filePath error : nil ] fileSize ];
  }
  return 0 ;
}
//遍历文件夹获得文件夹大小，返回多少 M
+ (float)folderSizeAtPath:(NSString *)folderPath {
  NSFileManager * manager = [ NSFileManager defaultManager];
  if (![manager fileExistsAtPath :folderPath]) return 0 ;
  NSEnumerator *childFilesEnumerator = [[manager subpathsAtPath :folderPath] objectEnumerator ];
  NSString * fileName;
  long long folderSize = 0 ;
  while ((fileName = [childFilesEnumerator nextObject]) != nil ){
    NSString * fileAbsolutePath = [folderPath stringByAppendingPathComponent:fileName];
    folderSize += [self fileSizeAtPath:fileAbsolutePath];
  }
  return folderSize / (1024.0 * 1024.0);
}

// 清理缓存
+ (void)clearCache {
  NSString *cachPath = [NSSearchPathForDirectoriesInDomains (NSCachesDirectory, NSUserDomainMask, YES ) firstObject ];
  NSArray *files = [[ NSFileManager defaultManager] subpathsAtPath:cachPath];
  for (NSString *p in files) {
    NSError *error = nil ;
    NSString *path = [cachPath stringByAppendingPathComponent:p];
    if ([[NSFileManager defaultManager] fileExistsAtPath:path]) {
        [[NSFileManager defaultManager] removeItemAtPath:path error:&error];
    }
  }
}

// 删除沙盒里的文件
+ (void)deleteFileWithFilePath:(NSString *)filePath {
  NSFileManager* fileManager=[NSFileManager defaultManager];
  NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
  //文件名
  NSString *uniquePath=[[paths objectAtIndex:0] stringByAppendingPathComponent:filePath];
  if ([fileManager fileExistsAtPath:uniquePath]) {
    [fileManager removeItemAtPath:uniquePath error:nil];
  }
}

再来看Swift获取文件大小，清除缓存，删除沙盒里文件的代码

// 显示缓存大小
func cacheSize() -> CGFloat {
  let cachePath = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.cachesDirectory, FileManager.SearchPathDomainMask.userDomainMask, true)[0]
  return folderSize(filePath: cachePath)
}

//计算单个文件的大小
func fileSize(filePath: String) -> UInt64 {
  let manager = FileManager.default
  if manager.fileExists(atPath: filePath) {
    do {
        let attr = try manager.attributesOfItem(atPath: filePath)
        let size = attr[FileAttributeKey.size] as! UInt64
        return size
    } catch  {
        print("error :\(error)")
        return 0
    }
  }
  return 0
}

//遍历文件夹，返回多少M
func folderSize(filePath: String) -> CGFloat {
  let folderPath = filePath as NSString
  let manager = FileManager.default
  if manager.fileExists(atPath: filePath) {
    let childFilesEnumerator = manager.enumerator(atPath: filePath)
    var fileName = ""
    var folderSize: UInt64 = 0
    while childFilesEnumerator?.nextObject() != nil {
        fileName = childFilesEnumerator?.nextObject() as! String
        let fileAbsolutePath = folderPath.strings(byAppendingPaths: [fileName])
        folderSize += fileSize(filePath: fileAbsolutePath[0])
    }
    return CGFloat(folderSize) / (1024.0 * 1024.0)
  }
  return 0
}

// 清除缓存
func clearCache() {
  let cachPath = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.cachesDirectory, FileManager.SearchPathDomainMask.userDomainMask, true)[0] as NSString
  let files = FileManager.default.subpaths(atPath: cachPath as String)
  for p in files! {
    let path = cachPath.appendingPathComponent(p)
    if FileManager.default.fileExists(atPath: path) {
        do {
            try FileManager.default.removeItem(atPath: path)
        } catch {
            print("error:\(error)")
        }
    }
  }
}

//删除沙盒里的文件
func deleteFile(filePath: String) {
  let manager = FileManager.default
  let path = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true)[0] as NSString
  let uniquePath = path.appendingPathComponent(filePath)
  if manager.fileExists(atPath: uniquePath) {
    do {
        try FileManager.default.removeItem(atPath: uniquePath)
    } catch {
        print("error:\(error)")
    }
  }
}