Question

I currently have a view that is contained on a view. The main view controller (parent view) has a property that is hooked up in interface builder to the subview. The subview contains a button. I want the button to flip the subview while keeping the main view stationary. I currently have the following code in my IBAction for the button:

[UIView transitionWithView: self.subViewFront
                  duration: 1.0
                   options: UIViewAnimationOptionTransitionFlipFromTop
                animations: nil
                completion: nil];
[UIView commitAnimations];
[[self view] addSubview: self.subViewBack;

This code works great, however I noticed the following when looking at the API reference from Apple:

Use of the methods in this section is discouraged in iOS 4 and later.
Use the block-based animation methods instead.

Following this advice I attempted to use the following code:

[UIView transitionFromView: self.subViewFront
                    toView: self.subViewBack
                  duration: 1.0
                   options: UIViewAnimationOptionTransitionFlipFromTop
                completion: nil];

It looks like it should do the same as what I originally coded, however, when I run my app with this code, it flips my entire view (parent and child view) instead of just the subview. Should this method be used as a substitution from the original method I have used, or is there something I’m missing? Thanks.

Answer 1

I had the same issue (with the parent getting animated instead), but resolved it by adding the two views (subViewFront and subViewBack) to a container view instead.

So add your two views to a container UIView instead, then use the -transitionFromView:... just like your example says:

UIView *container = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)] autorelease];
[self.view addSubview:container];

...

[container addSubview:self.subViewFront];
[container addSubview:self.subViewBack];