Hour 2. Handling Interaction

What You’ll Learn in This Hour: Understanding Objective-C objects Binding an object to the user interface Managing memory Invoking methods on nil Understanding Objective-C type checking

Now that you’ve installed the development tools and you’ve built a basic Calculator UI, it is time to make it useful. You’ll write code to give your calculator the ability to do arithmetic. As all iPhone code is written in Objective-C, you start learning Objective-C this hour. I cover the Objective-C objects, memory management, invoking methods on nil, and Objective-C type checking. You’ll also learn how to bind an object to the UI and how to debug with NSLog().