Implementing the Collection View Data Source Methods
After all the objects are configured in Interface Builder, the data source methods need to be implemented for the collection view to work. Confirm that the collection view object in the storyboard has the data source set to the basic flow view controller, as shown in Figure 20.5.
The sample app is a gallery app that displays photos from the user’s photo library, so there is logic implemented in the
viewDidLoad method that builds an array of image assets (organized as an array containing asset arrays, in which each asset array ...