UIView vertical flip animation

Just write your own method for the flip using Core Animation Transforms.

- (void)verticalFlip{
    [UIView animateWithDuration:someDuration delay:someDelay animations:^{
        yourView.layer.transform = CATransform3DMakeRotation(M_PI,1.0,0.0,0.0);
    } completion:^{
        // code to be executed when flip is completed
    }];
}

Make sure you have the Core Animation libraries/frameworks added and included and also have included math.h if you want to use the M_PI notation.

EDIT:

To have it essentially "change" the view when it's halfway flipped do something like this:

- (void)verticalFlip{
    [UIView animateWithDuration:someDuration delay:someDelay animations:^{
        yourView.layer.transform = CATransform3DMakeRotation(M_PI_2,1.0,0.0,0.0); //flip halfway
    } completion:^{
        while ([yourView.subviews count] > 0)
            [[yourView.subviews lastObject] removeFromSuperview]; // remove all subviews
        // Add your new views here 
        [UIView animateWithDuration:someDuration delay:someDelay animations:^{
            yourView.layer.transform = CATransform3DMakeRotation(M_PI,1.0,0.0,0.0); //finish the flip
        } completion:^{
            // Flip completion code here
        }];
    }];
}

This could also work:

- (void)verticalFlip{

    // Do the first half of the flip
    [UIView animateWithDuration:someDuration delay:someDelay animations:^{
        yourView.layer.transform = CATransform3DMakeRotation(M_PI_2,1.0,0.0,0.0); //flip halfway
    } completion:^{
        while ([yourView.subviews count] > 0)
            [[yourView.subviews lastObject] removeFromSuperview]; // remove all subviews
        // Add your new views here 
    }];

    // After a delay equal to the duration+delay of the first half of the flip, complete the flip
    [UIView animateWithDuration:someDuration delay:durationOfFirstAnimation animations:^{
        yourView.layer.transform = CATransform3DMakeRotation(M_PI,1.0,0.0,0.0); //finish the flip
    } completion:^{
        // Flip completion code here
    }];
}

Cheers.

UIViewAnimationOptionTransitionFlipFromTop is easy to use, but we can not create an interactive transition using UIViewAnimationOptionTransitionFlipFromTop. We need change layer’s transform to create an interactive transition.

Just create a transform using CATransform3DMakeRotation is not enough, no light effect, no perspective. I write an sample to add these effect. You can change it to an interactive transition easily.

Demo:

Sample code:

CALayer *sideALayer = sideAView.layer;
CALayer *sideBLayer = sideBView.layer;
CALayer *containerLayer = containerView.layer;

sideALayer.opacity = 1;
sideBLayer.opacity = 0;
sideBLayer.transform = CATransform3DMakeRotation(M_PI, 0, 1, 0);
containerLayer.transform = CATransform3DIdentity;

CATransform3D perspectiveTransform = CATransform3DIdentity;
perspectiveTransform.m34 = -1.0 / containerViewWidth;
[UIView animateKeyframesWithDuration:1 delay:0 options:UIViewKeyframeAnimationOptionCalculationModeLinear animations:^{

    [UIView addKeyframeWithRelativeStartTime:0 relativeDuration:0.5 animations:^{
        sideALayer.opacity = 0;
        containerLayer.transform = CATransform3DConcat(perspectiveTransform,CATransform3DMakeRotation(M_PI_2, 0, 1, 0));
    }];
    [UIView addKeyframeWithRelativeStartTime:0.5 relativeDuration:0.5 animations:^{
        sideBLayer.opacity = 1;
        containerLayer.transform = CATransform3DConcat(perspectiveTransform, CATransform3DMakeRotation(M_PI, 0, 1, 0));
    }];
} completion:nil];

sideAView and sideBView are subviews of containerView.

The containerView is set a black background.

The code from Brenton didn't work for me so I did a little more digging through the apple docs and found this piece of code for an horizontal flip:

- (IBAction)toggleMainViews:(id)sender {
    [UIView transitionFromView:(displayingPrimary ? primaryView : secondaryView)
                        toView:(displayingPrimary ? secondaryView : primaryView)
                      duration:1.0
                       options:(displayingPrimary ? 
                                    UIViewAnimationOptionTransitionFlipFromRight :
                                    UIViewAnimationOptionTransitionFlipFromLeft)
                    completion:^(BOOL finished) {
                                   if (finished) {
                                       displayingPrimary = !displayingPrimary;
                                   }
                              }
    ];
}

You can do a vertical flip by changing the options from UIViewAnimationOptionTransitionFlipFromRight : UIViewAnimationOptionTransitionFlipFromLeft to UIViewAnimationOptionTransitionFlipFromTop : UIViewAnimationOptionTransitionFlipFromBottom.

Worked like a charm.

As of iOS 5.0, there's no need to write your own Core Animation transformation to do vertical flips. Just use UIKit's UIViewAnimationOptionTransitionFlipFromTop and UIViewAnimationOptionTransitionFlipFromBottom transitions, and all this stuff becomes a single method call.

These behave analagously to UIViewAnimationOptionTransitionFlipFromLeft and UIViewAnimationOptionTransitionFlipFromRight (which have been around since iOS 2.0).

Example usage:

[UIView transitionFromView:viewToReplace
                    toView:replacementView
                  duration:1
                   options:UIViewAnimationOptionTransitionFlipFromBottom
                completion:nil];

The above code will vertically flip the superview of viewToReplace. At the halfway point in the animation, at the instant when the superview is perpendicular to the screen and thus invisible, viewToReplace gets replaced by replacementView.

It's that easy.