The UICollectionView operates in a similar way to UITableView. While UITableView manages a collection of data items and displays them on screen in a single-column layout, the UICollectionView class offers developers the flexibility to present items using customizable layouts. By default, the SDK comes with a UICollectionViewFlowLayout class that organizes items into a grid with optional header and footer views for each section.

(The UICollectionView class manages an ordered collection of data items and presents them using customizable layouts. Collection views provide the same general function as table views except that a collection view is able to support more than just single-column layouts. Collection views support customizable layouts that can be used to implement multi-column grids, tiled layouts, circular layouts, and many more. You can even change the layout of a collection view dynamically if you want.)

The UICollectionView is composed of several components:

* Cells – instances of UICollectionViewCell. Like UITableViewCell, a cell represents a single item in the data collection. The cells are the main elements organized by the associated layout. If a UICollectionViewFlowLayout is used, the cells are arranged in a grid-like format.

* Supplementary views – Optional. It’s usually used to implement the header or footer views of sections. (We’ll cover this in the next tutorial)

* Decoration views – think of it as another type of supplementary view but for decoration purpose only. The decoration view is unrelated to the data collection. We simply create decoration views to enhance the visual appearance of the collection view. (We’ll cover this in the next tutorial)