iOS Programming: The Big Nerd Ranch Guide

Passing Data Around

When a row in the table view is tapped, you need a way of telling the DetailViewController which item was selected. Whenever a segue is triggered, the prepareForSegue(_:sender:) method is called on the view controller initiating the segue. This method has two arguments: the UIStoryboardSegue, which gives you information about which segue is happening, and the sender, which is the object that triggered the segue (a UITableViewCell or a UIButton, for example).

The UIStoryboardSegue gives you three pieces of information: the source view controller (where the segue originates), the destination view controller (where the segue ends), and the identifier of the segue. The identifier lets you differentiate segues. Let’s ...