In the preceding chapter, I wrote that
UICollectionViewFlowLayout is great for line-based, breaking layouts and that you should always resort to using it first. Sometimes, however, our layouts are sufficiently complicated to warrant the use of something more powerful.
UICollectionViewLayout is the superclass of
UICollectionViewFlowLayout and it is hands on. You are responsible for everything—the layout of cells, the size of the collection view—everything. We’ll take a look at an example where you’d want to use it, revisit decoration views, and explore a little bit of changing between layouts programmatically with animation. At the end of this chapter, we build a really cool photos application ...