iOS App Development Portable Genius

Playing Sounds and Videos

iOS is capable of complex real-time sound synthesis. But a full introduction to all the features in Core Audio, Media Player, and the other media frameworks would need a much bigger book.

Fortunately, you don’t need to be an expert on synthesis to play a simple sound. You can use a class called AVAudioPlayer to load a sound and play it with just a few lines of code.

Playing a sound with AVAudioPlayer

The AVAudioPlayer class provides simple playback of sampled audio files. The class can do much, and it’s easy to work with. But you must add extra setup code to load a file you package with your app and optionally to handle errors.

AVAudioPlayer is part of the AVFoundation framework. Don’t forget to add this framework to your build and include its headers in your project before you work with it.

Files and URLs in iOS

You’re almost certainly used to the idea that files are collections of data stored on disk and URLs are online addresses.

iOS (and OS X) blurs this distinction. In iOS, you can load any file—local or remote—by specifying a URL instead of a file path. The NSURL object can hold a representation of a local file path or an online URL. Both are stored in a special format. Objects that can use NSURL for file access don’t care whether the URL points to local or online storage.

This makes it very easy to download content from the Internet. For example, ...