去掉UIActionSheet第一个按钮红色

 self.shareSheet = [[UIActionSheet alloc] initWithTitle:@"邮件转发" 

  delegate:self

  cancelButtonTitle:nil

destructiveButtonTitle:nil

  otherButtonTitles: nil];

shareSheet.actionSheetStyle = UIActionSheetStyleBlackOpaque;

[shareSheet addButtonWithTitle:@"短信转发"];

[shareSheet addButtonWithTitle:@"邮件转发"];

    [shareSheet addButtonWithTitle:@"取消"];

    self.shareSheet.actionSheetStyle=UIActionSheetStyleBlackOpaque;