popToViewController用法
方式一，不推薦
[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:2] animated:YES];

方式二，推薦
或（推薦下面這種，不受后期控制器數(shù)量影響）
for (UIViewController *controller in self.navigationController.viewControllers) {
if ([controller isKindOfClass:[你要跳轉(zhuǎn)到的Controller class]]) {
[self.navigationControllerpopToViewController:controller animated:YES];
}
}

方式三，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）
// 需要返回調(diào)用的
MyIMPPlanController *myIMPVC = nil;
for (int i = 0; i < self.navigationController.viewControllers.count; i++) {

    CustomViewController *cv = self.navigationController.viewControllers[i];
    if ([cv isKindOfClass:[MyIMPPlanController class]]) {
        
        myIMPVC = (MyIMPPlanController *)cv;
        break;
    }
}

[self.navigationController popToViewController:myIMPVC animated:YES];
[myIMPVC refreshData];