Mastering iOS Frameworks: Beyond the Basics, Second Edition

21. Collection Views

Collection views were added in iOS 6 to provide a convenient new way to display scrollable cell-based information in a view with arbitrary layouts. Consider the iOS 6+ versions of Photos.app, which present thumbnails of images in a scrollable grid. Before iOS 6, implementing a grid view would require setting up a table view with logic to calculate which thumbnail (or cell) should go in each position in each table row, or would require custom logic to place thumbnails in a scroll view and manage them all as scrolling occurs. Both approaches are challenging, time-consuming, and error prone to implement. Collection views address this situation by providing a cell-management architecture that is similar to row management in a ...