To begin programming with Android, you need a computer that runs one of the following operating systems:
Windows XP (32 bit), Vista (32 or 64 bit), or Windows 7 or 8 (32 or 64 bit)
Mac OS X (Intel) 10.5.8 or later (x86 only)
You also need to download the Android SDK (which is free) and the Java Development Kit (or JDK, which is also free), if you don’t already have them on your computer. Chapter 2 outlines the entire installation process for all the tools and frameworks.
Because Android applications are developed in the Java programming language, you need to understand the Java language. Android also uses XML quite heavily to define various resources inside the application, so you should understand XML too. You don’t have to be an expert in these languages, however.
You don’t need a physical Android device, because all the applications you build in this book work on an emulator.