（推薦下面這種关炼，不受控制器數(shù)量影響）
for (UIViewController *controller in self.navigationController.viewControllers) {
if ([controller isKindOfClass:[Controller class]]) {
[self.navigationController ?popToViewController:controller animated:YES];
}
}
方式三择懂，推薦? 這種方式適合返回指定控制器并調(diào)用其方法（比如刷新什么的）// 需要返回調(diào)用的
MylanController *myIVC = nil;
for (int i = 0; i < self.navigationController.viewControllers.count; i++) {
CustomViewController *cv = self.navigationController.viewControllers[i];
if ([cv isKindOfClass:[MylanController class]]) {
myIVC = (MylanController *)cv;
break;
}}
[self.navigationController? popToViewController:myIVC animated:YES];
[myIVC refreshTableView];
