The previous chapter showed you how to build a list of items using a table view. In this chapter, you'll learn how to display the same items using a more flexible component. This component is called UICollectionView, and it has a very similar interface to UITableView. The most significant difference is that you can define a much more flexible layout using a collection view. An example of this is the grid layout that UICollectionView provides out of the box. Of course, you are free to implement any layout you want for a collection view. This is probably the most significant advantage a collection view has to offer.
You will build on top of Hello-Contacts by refactoring the existing application to switch from a table view to a collection view. You are going to replace all table-view-related configuration code with its collection view counterparts. You will also make use of a grid layout to show contacts. Lastly, you will create a custom collection...