如何返回上一个界面并传值给上一个界面

- (void) goBackToPersonInfoVCWithNickName:(NSString *) nickName{    //            [self.navigationController popViewControllerAnimated:YES];    //此页面已经存在于self.navigationController.viewControllers中,并且是当前页面的前一页面    PersonInfoViewController *personVC = [self.navigationController.viewControllers objectAtIndex:self.navigationController.viewControllers.count-2];    //初始化其属性    //            personVC.sexInt = _sex;    //传递参数过去    personVC.nickName = nickName;    //使用popToViewController返回并传值到上一页面    [self.navigationController popToViewController:personVC animated:true];    }