52.4 Handling UIKit Delegation and Data Sources
Delegation is a feature of UIKit that allows an object to pass the responsibility for performing one or more tasks on to another object and is another area in which extra steps may be necessary if events are to be handled by a wrapped UIView.
The UIScrolledView, for example, can be assigned a delegate which will be notified when certain events take place such as the user performing a scrolling motion or when the user scrolls to the top of the content. The delegate object will need to conform to the UIScrolledViewDelegate protocol and implement the specific methods that will be called automatically when corresponding events take place in the scrolled view.
Similarly, a data source is an object which provides a UIView based component with data to be displayed. The UITableView class, for example, can be assigned a data source object to provide the cells to be displayed in the table. This data object must conform with the UITableViewDataSource...
