注意[self.navigationController pushViewController:MyVC animated:NO]; 设置成NO
CATransition *animation = [CATransition animation];
[animation setDuration:0.3];
[animation setType: kCATransitionMoveIn];
[animation setSubtype: kCATransitionFromTop];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault]];
[self.navigationController pushViewController:MyVC animated:NO];
[self.navigationController.view.layer addAnimation:animation forKey:nil];
