Changes

Since the iOS 4 AVAudioRecorder class is part of the AV Foundation framework it will be necessary to add the framework to the project. This can be achieved by selecting the product target entry from the project navigator panel (the top item named ''record'') and clicking on the ''Build Phases'' tab in the main panel. In the ''Link Binary with Libraries'' section click on the ‘+’ button, select the ''AVFoundation.framework'' entry from the resulting panel and click on the Add button.

The completed iPad application will need instances of the AVAudioPlayer and AVAudioRecorder classes, a range of outlets for the user interface buttons and play, stop and record action methods. It will also be necessary to import the ''<AVFoundation/AVFoundation.h>'' file and declare that the view controller is going to implement the AVAudioRecorderDelegate and AVAudioPlayerDelegate protocols. Bringing all of these requirements together results in a modified ''recordViewController.h'' file that reads as follows: