用户文件夹防止备份到iCloud

//用户文件夹防止备份到iCloud

• (BOOL)addSkipBackupAttributeToItemAtURL:(NSURL *)URL{
  assert([[NSFileManager defaultManager] fileExistsAtPath: [URL path]]);

  NSError *error = nil;
  BOOL success = [URL setResourceValue: [NSNumber numberWithBool: YES]
  forKey: NSURLIsExcludedFromBackupKey error: &error];
  if(!success){
  NSLog(@"Error excluding %@ from backup %@", [URL lastPathComponent], error);
  }
  return success;
  }