The iOS SDK

To write an iPhone application, you have to install Xcode and the iOS SDK. This SDK is available free of charge from Apple’s Web site. To download the SDK, you’ll need to first register to be an Apple Developer. That process is also free. To get the appropriate links, you can start at developer.apple.com and navigate to the appropriate point. It’s a great idea to become familiar with that site.

The discussions in this chapter are based on Xcode 4 and the iOS SDK for iPhone OS 4.3. Later versions of either should be compatible with what’s described here. If you notice your screens look different than those shown, it may be because you’re using a different version of Xcode. In that case, check the forum at classroomM.com/objective-c for current information.