iOS不同模式返回根视图的方法

pop回根视图

[self.navigationController popToViewController: [self.navigationController.viewControllers objectAtIndex: ([self.navigationController.viewControllers count] - 3)] animated:YES];

或者

[self.navigationController popToRootViewControllerAnimated:YES];

dismiss回根视图

if ([self respondsToSelector:@selector(presentingViewController)]){                        self.presentingViewController.view.alpha = 0;                        [self.presentingViewController.presentingViewController dismissViewControllerAnimated:YES completion:nil];                    }else {                        self.parentViewController.view.alpha = 0;                        [self.parentViewController.parentViewController dismissViewControllerAnimated:YES completion:nil];                    }