iOS做出仿present动画

//由于音视频聊天里头有音频和视频聊天界面的切换，直接用present的话页面过渡会不太自然，这里还是用push，然后做出present的效果

        AudioChatViewController *vc = [[AudioChatViewController alloc] init];
        CATransition *transition = [CATransition animation];
        transition.duration = 0.25;
        transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];
        transition.type = kCATransitionPush;
        transition.subtype = kCATransitionFromTop;
        [self.navigationController.view.layer addAnimation:transition forKey:nil];
        self.navigationController.navigationBarHidden = YES;
        [self.navigationController pushViewController:vc animated:NO];