在过渡期间对子视图控制器的视图进行动画处理

Question

I have a Master custom container view controller, whose purpose is to swap between two different view controllers that each manage a form with text fields. We'll call these FormVC1 and FormVC2. Both of these controllers's views are managed by a XIB.

I can successfully swap between FormVC1 and FormVC2 using:

transitionFromViewController:toViewController:duration:options:animations:completion: while passing UIViewAnimationOptionTransitionCrossDissolve for the options argument.

Now I want to sweeten the transition a little, and when FormVC1 is being dismissed, I want the individual text fields to fly off to the left (one at a time), and when FormVC2 is being presented, I want the individual text fields to fly in from the right, one at a time.

I'm a little confused as to how to set this all up, and where exactly to place the specific text field animation code. Do I put that in the animation block within Master? Do I put it in each FormVC's appearance callbacks?

Answer 1

You have a few options, so pick the one that works best for you:

1) Make the container view controller contain a scrollview, with scrolling disabled, and scrollbars disabled. Set the two form vc's as child vc's of the container, and add the views into the scrollview next to each other, so only one is visible. At the appropriate time, show the next form by setting the content offset of the scrollview with animated set to YES.

2) Even better (more easily extendible to add arbitrary number of forms), use a UICollectionView instead of a basic scrollview, set it to use the horizontal linear layout, make a custom cell to hold your form vc class (disable scrolling and scrollbars), then to show the next form, scrollToItemAtIndexPath:: should do the trick.

3) Most basic, maybe good enough: Make your container a navigation controller and just push the form vc with the default transition.

All these solutions assume your form vc's are only the controls you want animated and the main view has a transparent background.

Answer 2

In the animations block of transitionFromViewController:toViewController:… change the frames of the elements that you want to be animated. To make it fly off to the left, subtract something like 200 from the frame.origin.x . To make them fly in from the right, start at a high x value (maybe 500) and animate it to the center.

To animate them sequentially, you could use different x values for each element. For something more complex, use animateWithDuration:delay:options:animations:completion: and set up the next animation in the former's completion block. You'd use that instead of transitionFromViewController:toViewController:… .