用presentingViewController实现左右切换视图

   没有导航栏时实现导航栏左右切换视图的效果 

    CATransition *transition = [CATransition animation];

    transition.duration = 0.3;

    transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

    transition.type = kCATransitionPush;

    transition.subtype = kCATransitionFromLeft;

    [self.view.window.layer addAnimation:transition forKey:nil];

    [self presentingViewController:VC Animated:NO completion:nil];