7.3. Important protocols

Now that you’ve seen all the guts of making and implementing a protocol, let’s look at the most popular protocols used in the development of an iPhone application. Apple relies on the protocol design method for many of its Cocoa classes. In this section we review four sets of protocols that you’ll likely use when developing your application. Let’s dive in.

7.3.1. <UITableViewDataSource>

The UITableViewDataSource protocol is a mandatory protocol to have implemented for any table view in your application. A table view is a visual element that’s meant to display some collection of information. Unlike any other user interface element in the iPhone UIKit, UITableView must be provided the data it’ll display. Without the data source protocol for a UITableView connected, a table view has no functionality. Let’s look at the required methods of this protocol and then look at some of the more popular optional methods.