Apple’s UIDocument class is almost mandatory if you are going to be interacting with iCloud. Although, in theory, you can get by without using, there are a lot of file locking and other related concerns that it handles for you. Even if you’re not using iCloud, it makes for a nice way to save and load data from your application files. When writing your extension to UIDocument, there are a number of things you should beware of in order to have a robust application. This is what we will discuss in this tutorial.
