uinavgationcontroller

[self.navigationController popToRootViewControllerAnimated:NO];

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
viewController.hidesBottomBarWhenPushed = YES;
[super pushViewController:viewController animated:animated];
}

MJLoginViewController *login = [[MJLoginViewController alloc]init];
UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:login];
[self.navigationController presentViewController:nav animated:NO completion:nil];