Introduction

For iPhone applications that use view objects to draw content to the screen, view controllers provide a vital link between those view objects and the rest of the application. View controllers are traditional controller objects in the Model-View-Controller design paradigm but they also provide much more. In iPhone applications, view controllers provide much of the logic needed to manage basic application behaviors. For example, view controllers manage the presentation and removal of content from the screen and they manage the reorientation of views in response to device orientation changes.

Who Should Read This Document?

Understanding when and how to use view controllers is crucial to the design of iPhone applications. View controllers provide fundamental infrastructure that makes it easier for you to implement your applications and ensures that your applications behave consistently with the platform’s interface guidelines. Of course, the basic features provided by view controllers can only go so far. At some point, your custom code must take over to present your custom content. This document shows you what behaviors view controllers provide and where you can customize those behaviors to suit your own needs.

Prerequisites

Before you start reading this document, you should have at least a fundamental understanding of the following Cocoa concepts:

• Basic information about Xcode and Interface Builder and their role in developing applications

• How to define new Objective-C classes

• How to manage memory, including how to create and release objects in Objective-C

• The role of delegate objects in managing application behaviors

• A basic understanding of the Model-View-Controller paradigm

Developers who are new to Cocoa and Objective-C can get information about all of these topics in Cocoa Fundamentals Guide.

Development of iPhone applications requires an Intel-based Macintosh computer running Mac OS X v10.5 or later. You must also download and install the iPhone SDK. For information about how to get the iPhone SDK, go to http://developer.apple.com/iphone/.

Organization of This Document

This document contains the following chapters:

• “About View Controllers” provides an overview of view controllers and the role they play in iPhone applications.

• “Custom View Controllers” describes the basic behaviors supported by all view controllers and how you can create custom view controllers for use in your application.

• “Navigation Controllers” shows you how to create and configure navigation controllers.

• “Tab Bar Controllers” shows you how to create and configure tab bar controllers.

• “Modal View Controllers” shows you how to present view controllers modally and offers guidance on when to do so.

• “Combined View Controller Interfaces” shows you how to mix different types of view controllers to create sophisticated user interfaces.

Providing Feedback

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If you encounter bugs in Apple software or documentation, you are encouraged to report them to Apple. You can also file enhancement requests to indicate features you would like to see in future revisions of a product or document. To file bugs or enhancement requests, go to the Bug Reporting page of the ADC website:

http://developer.apple.com/bugreporter/

You must have a valid ADC login name and password to file bugs. You can obtain a login name for free by following the instructions found on the Bug Reporting page.

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