ios - WatchKit API for Force Touch / Digital Crown?

Question

I'm very excited about the new user interaction possibilities introduced by the Apple Watch, among them, Force Touch and Digital Crown.

However, I couldn't find mentions of them in the WatchKit API. Are there any ways to receive events from Force Touch / Digital Crown? Is it possible to have custom handlers for the events?

Answer 1

watchOS 3 adds WKCrownSequencer and WKCrownDelegate to report the state of the digital crown (such as rotational speed), as well as to receive notifications when the user rotates the crown.

You can use the crown sequencer to provide general input to control scenes or interface objects.

Apple has updated their WatchKit Catalog sample code to include a WKInterfaceController crown sequencer example demonstrating how to use the Apple Watch digital crown to interact with other objects:

class CrownDetailController: WKInterfaceController, WKCrownDelegate {
    @IBOutlet var velocityLabel: WKInterfaceLabel!
    @IBOutlet var stateLabel: WKInterfaceLabel!
    @IBOutlet var pickerView: WKInterfacePicker!

    override func awake(withContext context: AnyObject?) {
        super.awake(withContext: context)

        let itemList: [(String, String)] = [
            ("Item 1", "Red"),
            ("Item 2", "Green"),
            ("Item 3", "Blue")
        ]
        let pickerItems: [WKPickerItem] = itemList.map {
            let pickerItem = WKPickerItem()
            pickerItem.caption = $0.0
            pickerItem.title = $0.1
            return pickerItem
        }
        pickerView.setItems(pickerItems)

        crownSequencer.delegate = self
    }

    override func willActivate() {
        // This method is called when watch view controller is about to be visible to user
        super.willActivate()
        crownSequencer.focus()
    }

    @IBAction func focusCrown(sender: AnyObject) {
        crownSequencer.focus()
    }

    func updateCrownLabels() {
        velocityLabel.setText(String(format: "RPS: %2.2lf", crownSequencer.rotationsPerSecond))
        stateLabel.setText(crownSequencer.isIdle ? "Idle: true" : "Idle: false")
    }

    func crownDidBecomeIdle(_ crownSequencer: WKCrownSequencer?) {
        updateCrownLabels()
    }

    func crownDidRotate(_ crownSequencer: WKCrownSequencer?, rotationalDelta: Double) {
        updateCrownLabels()
    }

}