Apple Watch is the sort of science-fiction gadget that people used to dream about as kids. What kinds of apps do you envision for this new device? If you're comfortable using OS X, Xcode, and iOS-and familiar with Swift-this concise book shows you the basics of building your own apps for this wrist-mounted computer with Apple's WatchKit framework. You'll learn what an Apple Watch is, what it isn't, and how and why people might interact with apps you build for it. This practical guide also examines the type of apps most suitable for this device, and shows you how to be a good citizen in the iOS/Watch ecosystem. Learn the Watch app lifecycle, and understand how these apps interact with the user's iPhone Build a Watch app and its iOS counterpart by adding controls, working with multiple screens, and sharing data Design a simple glance, the non-interactive Watch component that provides quick-look information Add functionality to the notification system, including actionable items, and display them on the Watch face Design and build complications, Watch-face gadgets that can display quick snapshots of information, including future events with Time Travel