Developing for Apple Watch

Chapter 8Communicating with the Outside World

So far in this book you’ve seen WatchKit’s capabilities, so you know you can make some pretty amazing apps for Apple Watch. These watch interfaces on their own, powerful as they can be, pale in comparison to what you can do in your iPhone app. Fortunately, WatchKit gives us the best of both worlds. Your watch app can focus on what it does best—giving users quick, timely access to their data and delegating the rest to your iPhone app, even in the background. By using the iPhone as your processor to do the heavy lifting, you save battery life on the watch and avoid having to write the same code twice. In this chapter, you’ll learn about ways your WatchKit extension and iPhone app can communicate back ...