iOS 6 Programming Cookbook

1.16. Adding Properties to Classes

Problem

You want to add properties to your classes so that you can take advantage of dot notation to access those values, as opposed to using methods on your classes.

Solution

Define properties in your classes using the @property keyword.

Discussion

Anything addressed via dot notation is a property, which is a shortcut to a method. What does that mean? Well, let’s have a look at an example:

NSObject *myObject = [[NSObject alloc] init];
myObject.accessibilityHint = @"Some string";

You can see that we allocated and initialized an object of type NSObject and used dot notation to access a property called accessibilityHint in that object. Where did accessibilityHint come from?

It’s quite simple. A property is defined using the @property keyword. In fact, if you hold down the Command key on your keyboard in Xcode, and simply click on the accessibilityHint property in the example that we just saw, you will be redirected to the NSObject.h file where you will see this:

@property(nonatomic, copy) NSString *accessibilityHint;

But what is a property? It is a high-level language feature—a shortcut, if you will—that allows developers to easily access getters and setter methods on instances of a class without having to refer to the getter and/or the setter method at all. If you want to set a property’s value, you simply use the equals sign to do so. If you want to read from the property, you simply point to it using dot notation.

Let’s look at this in detail. In Recipe 1.12 ...