Telling Users the News: Alerts and NSError
This Part of the book focuses on user interaction. You’ve already seen how to interact with users through view controllers and interface elements, but the user interaction discussed in this part of the book is a different type. These interactions are initiated by the app itself. Some of them not only are initiated by the app but they also take precedence over what the user may be trying to do at the time. The user indirectly initiates other types of app-initiated interactions. For example, as you will see in Chapter 17, “Back to the Storyboard: Enhancing the Interface,” when a user creates a new object such as a party, it is common to immediately ask the user to provide a name for that object. The user action of creating a new object is followed by the app-initiated request for a name.
There are a variety of tools you can use to communicate with users. This chapter provides an overview of presenting information to the users. In Chapter 16, “Getting Input from Users: Alerts and Action Sheets,” you find a discussion of the primary tools for getting information from users: modal views and popovers (popovers are available only on iPad).
Of course, alerts, action sheets, modal views, notifications, and badges are each different elements of the Cocoa Touch framework. Nevertheless, they are all used to implement communication with the user, and that interaction is two-way. Although a modal view may be the easiest way to get ...