I've been animating some mobile interactions for an ecommerce app that will sell premium sake. This was created in After Effects to prototype the various interactions.
Flickr - Best iOS 7 Animations
A very nice, creative animation! The input underline arises from the line icon in a very slick way. The only thing I'm not sure of, is if it's smart to hide the icon. I guess some people really use it to submit their search.