iOS判断当前ViewController是push还是present方式显示的

我本来试用方法：

- (IBAction)dismiss:(id)sender {
    if ([self respondsToSelector:@selector(dismissViewControllerAnimated:completion:)]) {
        //判断1
        [self dismissViewControllerAnimated:YES completion:nil];
    } else if ([self.navigationController respondsToSelector:@selector(popViewControllerAnimated:)]) {
        //判断2
        [self.navigationController popViewControllerAnimated:YES];
    }
}

结果发现不管是push或present，都只进判断1，不进判断2.
于是google，

方法一：

通过判断self有没有present方式显示的父视图presentingViewController

- (IBAction)dismiss:(id)sender {
    if (self.presentingViewController) {
        [self dismissViewControllerAnimated:YES completion:nil];
    } else {
        [self.navigationController popViewControllerAnimated:YES];
    }
}

方法二：

通过判断self.navigationController.viewControllers的最后一个是否是当前控制器，或者self.navigationController.topViewController == self

- (IBAction)dismiss:(id)sender {
    if (self.navigationController.topViewController == self) {
        [self.navigationController popViewControllerAnimated:YES];
    } else {
        [self dismissViewControllerAnimated:YES completion:nil];
    }
}