In this chapter, you are going to create an iOS application: a simple to-do list application called iTahDoodle that stores its data as a property list. Here is what it will look like when you are done.
We have intentionally kept this chapter and this application very simple. It is not intended to prepare you to build iOS apps on your own, but it will give you a quick taste of iOS development. It introduces some important concepts and patterns, and we hope that it will inspire you to dive into iOS programming after you have finished this book.
None of the programs that you have written so far have had a user interface. Now you are going to write an application that has a graphical user interface, or GUI.
A GUI-based application is event-driven. When the application is launched, it starts a run loop that sits and waits for events. Events can be generated by the user (like a button tap) or by the system (like a low-memory warning). When an event happens, the application leaps into action to respond to the specific event. All iOS applications are event-driven applications.