How to get references to some particular views in animateTransition:

How can I get my view controller to be notified that a transition is about to take place so I can use animateAlongsideTransition:completion:

Where there is a size change, there is viewWillTransitionToSize:withTransitionCoordinator but I can't find sometime for my case. Something like viewWillTransition:withViewCoordinator.

Creating Animations that Run Alongside a Transition

View controllers involved in a transition can perform additional animations on top of any presentation or transition animations. For example, a presented view controller might animate its own view hierarchy during the transition and add motion effects or other visual feedback while the transition occurs. Any object can create animations, as long as it is able to access the

transitionCoordinator

property of the presented or presenting view controller. The transition coordinator exists only while a transition is in progress.

To create animations, call the

animateAlongsideTransition:completion:

or

animateAlongsideTransitionInView:animation:completion:

method of the transition coordinator. The blocks you provide are stored until the transition animations begin, at which point they are executed along with the rest of the transition animations.

Using animateAlongsideTransition:completion: in viewWillAppear: and/or viewWillDisappear: seems the way go.