Swift Development for the Apple Watch

Chapter 1. Understanding the Apple Watch

Apple describes the Apple Watch as “a new chapter in the relationship people have with technology.” While it remains to be seen whether this is quite the case, the Apple Watch, as it exists right now, is a tiny programmable computer that sits on your wrist. It’s even smaller than Apple’s other recent tiny programmable computers.

watchOS apps are written using a framework called WatchKit. The code runs on the watch, but because the Apple Watch is tightly linked to the iPhone, writing apps for the Apple Watch also means writing an iOS app.

How Users Interact with Apple Watch

watchOS apps can provide four different components for the user: full apps, glances, notifications, and complications. You must always create a full Apple Watch app, which can be opened from the home screen of the Apple Watch.

• Full apps behave in a similar way to iPhone apps, and can have multiple screens and a range of possible interactions.

• Glances are single screens of content that can be accessed by swiping up from the watch face. They don’t have any interactive elements—they’re only for displaying information. If the user taps on the screen, the full app is launched.

• Notifications appear when the watchOS app’s counterpart iOS app receives a notification. Notifications usually come from the Apple Push Notification service, but they can also be “local” notifications, which the iOS app schedules for later delivery.

• Complications are small elements that are ...