iOS 7 Programming Cookbook

1.0. Introduction

iOS 7 has introduced a lot of new features to users, as well as tons of new APIs for us programmers to use and play with. You probably already know that the user interface has drastically changed in iOS 7. This user interface had stayed intact all the way from the first version of iOS till now, and because of this, many apps were coded on the assumption that this user interface would not ever change. Graphic designers are now faced with the challenge of creating the user interface and thinking about the user experience in a way that makes it great for both pre- and post-iOS 7 user interfaces (UIs).

In order to write apps for iOS 7, you need to know some of the basics of the Objective-C programming language that we will use throughout this book. Objective-C, as its name implies, is based on C with extensions that allow it to make use of objects. Objects and classes are fundamental in object-oriented programming (OOP) languages such as Objective-C, Java, C++, and many others. In Objective-C, like any other object-oriented language (OOL), you have not only access to objects, but also to primitives. For instance, the number –20 (minus twenty) can be expressed simply as a primitive in this way:

NSInteger myNumber = -20;

This simple line of code will define a variable named myNumber with the data type of NSInteger and sets its value to 20. This is how we define variables in Objective-C. A variable is a simple assignment of a name to a location in memory. In this case, when ...