Meet AccessorySetupKit

6:02 - Register event handler

import AccessorySetupKit

// Create a session
var session = ASAccessorySession()

// Activate session with event handler
session.activate(on: DispatchQueue.main, eventHandler: handleSessionEvent(event:))

// Handle event
func handleSessionEvent(event: ASAccessoryEvent) {  
    switch event.eventType {
    case .activated:
        print("Session is activated and ready to use")
        print(session.accessories)
    default:
        print("Received event type \(event.eventType)")
    }
}

7:23 - Create picker display items

// Create descriptor for pink dice
let pinkDescriptor = ASDiscoveryDescriptor()
pinkDescriptor.bluetoothServiceUUID = pinkUUID
// Create descriptor for blue dice
let blueDescriptor = ASDiscoveryDescriptor()
blueDescriptor.bluetoothServiceUUID = blueUUID

// Create picker display items
let pinkDisplayItem = ASPickerDisplayItem(
    name: "Pink Dice",
    productImage: UIImage(named: "pink")!,
    descriptor: pinkDescriptor
)
let blueDisplayItem = ASPickerDisplayItem(
    name: "Blue Dice",
    productImage: UIImage(named: "blue")!,
    descriptor: blueDescriptor
)

8:10 - Show picker

// Invoke accessory picker
Button {
    session.showPicker(for: [pinkDisplayItem, blueDisplayItem]) { error in
        if let error {
            // Handle error
        }
    }
} label: {
    Text("Add Dice")
}

9:26 - Handle events

// Handle event
func handleSessionEvent(event: ASAccessoryEvent) {  
    switch event.eventType {

    case .accessoryAdded:
        let newDice: ASAccessory = event.accessory!

    case .accessoryChanged:
        print("Accessory properties changed")

    case .accessoryRemoved:
        print("Accessory removed from system")

    default:
        print("Received event with type: \(event.eventType)")
    }
}

10:22 - Communicate with accessory

// Connect to accessory using CoreBluetooth
let central = CBCentralManager(delegate: self, queue: nil)

func centralManagerDidUpdateState(_ central: CBCentralManager) {
    switch central.state {
    case .poweredOn:
       // state will only be updated to poweredOn when you have paired accessories
        let peripheral = central.retrievePeripherals(withIdentifiers: [newDice.bluetoothIdentifier]).first
        central.connect(peripheral)
    default:
        print("Received event type \(event.eventType)")
    }
}

func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
    peripheral.delegate = self
    peripheral.discoverServices(pinkUUID)
}

11:58 - Migrate existing accessories

// Create migration items
let pinkMigration = ASMigrationDisplayItem(name: "Pink Dice", productImage: UIImage(named: "pink")!, descriptor: pinkDescriptor)
pinkMigration.peripheralIdentifier = pinkPeripheral.identifier

// Present picker with migration items
session.showPicker(for: [pinkMigration]) { error in
    if let error {
        // Handle error
    }
}