iOS navigationController中回到tabbarController根视图方法

根据需求来改变跳转：

[self.navigationController popToRootViewControllerAnimated:NO];[self dismissViewControllerAnimated:NO completion:^{            AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];            JKMainTabViewController *tab = (JKMainTabViewController *)delegate.window.rootViewController;            tab.selectedIndex = 0;        }];