WKInterfaceController

WKInterfaceController is a class in the WatchKit framework that manages a single screen of a watchOS app. Each interface screen in a WatchKit storyboard is associated with an interface controller, which coordinates the user interface elements (such as labels, buttons, and tables) and responds to user interactions.

WKInterfaceController inherits from NSObject and is instantiated by the system as the interface for a given scene. It works in conjunction with storyboard-defined interface objects (WKInterfaceLabel, WKInterfaceButton, WKInterfaceTable, etc.) and outlets/actions defined in the watchOS extension code. The controller’s content is typically configured based on data passed when the controller is presented.

The lifecycle of an interface controller includes several key methods. awake(withContext:) is called after the interface is loaded and receives an optional context object passed from the previous controller. willActivate() runs just before the interface becomes visible, suitable for refreshing dynamic content. didDeactivate() is called after the interface is no longer visible, useful for pausing tasks or releasing resources.

Navigation and data passage between controllers are achieved using several methods. Push navigation uses pushController(withName:context:), which adds a new interface controller to the navigation stack and provides context data to the new controller via awake(withContext:). Present navigation uses presentController(withNames:contexts:) to display one or more controllers modally or as a page-based interface. There are also methods to pop controllers (popController, popToRootController) and to replace the root interface stack with reloadRootControllers(withNames:contexts:).

In summary, WKInterfaceController is the core unit for managing watchOS interfaces, handling lifecycle, navigation, and data flow between screens within a WatchKit extension.