popToViewController的两种用法

From: http://snowyshell.blog.163.com/blog/static/220914034201362945418187/

第一种：

[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:1]animated:YES];

第二种：

for (UIViewController *temp in self.navigationController.viewControllers) {

            if ([temp isKindOfClass:[要跳转的Controller Class]]) {

                [self.navigationController popToViewController:temp animated:YES];

            }

        }

直接这样是不行的：

AviewController *A = [AviewController alloc]init];

[self.navigationController popToViewController:A animated:YES];