[self.navigationController pushViewController:viewController animated:YES];//从右向左的动画效果
[self.navigationController
presentModalViewController:viewController animated:YES];//从下向上的动画效果
[self.navigationController pushViewController:viewController animated:YES];//从右向左的动画效果
[self.navigationController
presentModalViewController:viewController animated:YES];//从下向上的动画效果