CoreBluetooth Advertising not starting - ios

Question

I am trying to write a simple app that constantly broadcasts a 'beacon' even when the app is not active. I know that using CoreLocation will switch this off when the app is not in use so I was trying to build a solution using Core Bluetooth.
The trouble is that I can't get the app to start advertising.
import UIKit
import CoreBluetooth
class ViewController: UIViewController, CBCentralManagerDelegate, CBPeripheralManagerDelegate {
var centralManager:CBCentralManager = CBCentralManager()
var peripheralManager:CBPeripheralManager = CBPeripheralManager()
let uuid:CBUUID = CBUUID(string: "DCEF54A2-31EB-467F-AF8E-350FB641C97B")
override func viewDidLoad() {
super.viewDidLoad()
self.peripheralManager = CBPeripheralManager(delegate: self, queue: nil)
self.centralManager.delegate = self
let advertisingData = [CBAdvertisementDataLocalNameKey:"my-peripheral", CBAdvertisementDataServiceUUIDsKey: uuid]
peripheralManager.startAdvertising(advertisingData)
centralManager.scanForPeripheralsWithServices([uuid], options: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func peripheralManagerDidStartAdvertising(peripheral: CBPeripheralManager, error: NSError?) {
print("started advertising")
print(peripheral)
}
func centralManager(central: CBCentralManager, didDiscoverPeripheral peripheral: CBPeripheral, advertisementData: [String : AnyObject], RSSI: NSNumber) {
print("peripheral discovered")
print("peripheral: \(peripheral)")
print("RSSI: \(RSSI)")
}
func centralManagerDidUpdateState(central: CBCentralManager) {
print("central state updated")
print(central.description)
if central.state == .PoweredOff {
print("bluetooth is off")
}
if central.state == .PoweredOn {
print("bluetooth is on")
let advertisingData = [CBAdvertisementDataLocalNameKey:"my-peripheral", CBAdvertisementDataServiceUUIDsKey: uuid]
let service = CBMutableService(type: uuid, primary: true)
self.peripheralManager.addService(service)
peripheralManager.startAdvertising(advertisingData)
centralManager.scanForPeripheralsWithServices(nil, options: nil)
}
if central.state == .Unsupported {
print("bluetooth is unsupported on this device")
}
}
func peripheralManagerDidUpdateState(peripheral: CBPeripheralManager) {
print("peripheral state updated")
print("\(peripheral.description)")
}
}
I have installed this on two devices, the issue seems to be in the transmission of the advert since peripheralManagerDidStartAdvertising() is never called.

Answer 1

The issue is related to immediate call .startAdvertising() right after .addService() call.
You must call .startAdvertising() ONLY after func peripheralManager(_ peripheral: CBPeripheralManager, didAdd service: CBService, error: Error?) delegate method is called.

Answer 2

If you use this init method the centralManagerDidUpdateState is going to work. You can set the CBCentralManagerScanOptionAllowDuplicatesKey option if you would like to see the beacons continually.
import UIKit
import CoreBluetooth
class ViewController: UIViewController, CBCentralManagerDelegate, CBPeripheralManagerDelegate {
var centralManager:CBCentralManager!
var peripheralManager:CBPeripheralManager = CBPeripheralManager()
let uuid:CBUUID = CBUUID(string: "DCEF54A2-31EB-467F-AF8E-350FB641C97B")
override func viewDidLoad() {
super.viewDidLoad()
self.peripheralManager = CBPeripheralManager(delegate: self, queue: nil)
self.centralManager = CBCentralManager(delegate: self, queue: nil)
let advertisingData = [CBAdvertisementDataLocalNameKey:"my-peripheral", CBAdvertisementDataServiceUUIDsKey: uuid]
peripheralManager.startAdvertising(advertisingData)
centralManager.scanForPeripheralsWithServices([uuid], options: [ CBCentralManagerScanOptionAllowDuplicatesKey : true])
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func peripheralManagerDidStartAdvertising(peripheral: CBPeripheralManager, error: NSError?) {
print("started advertising")
print(peripheral)
}
func centralManager(central: CBCentralManager, didDiscoverPeripheral peripheral: CBPeripheral, advertisementData: [String : AnyObject], RSSI: NSNumber) {
print("peripheral discovered")
print("peripheral: \(peripheral)")
print("advertisement: \(advertisementData)")
if let data = advertisementData["kCBAdvDataServiceData"] {
print("found advert data: \(data)")
}
print("RSSI: \(RSSI)")
}
func startAdvert(){
let advertisingData = [CBAdvertisementDataLocalNameKey:"my-peripheral", CBAdvertisementDataServiceUUIDsKey: uuid]
peripheralManager.startAdvertising(advertisingData)
}
func centralManager(central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: NSError?) {
print("peripheral disconnected")
print("peripheral: \(peripheral)")
}
func centralManagerDidUpdateState(central: CBCentralManager) {
print("central state updated")
print(central.description)
if central.state == .PoweredOff {
print("bluetooth is off")
}
if central.state == .PoweredOn {
print("bluetooth is on")
centralManager.scanForPeripheralsWithServices(nil, options: [ CBCentralManagerScanOptionAllowDuplicatesKey : true])
startAdvert()
}
if central.state == .Unsupported {
print("bluetooth is unsupported on this device")
}
}
func peripheralManagerDidUpdateState(peripheral: CBPeripheralManager) {
print("peripheral state updated")
print("\(peripheral.description)")
}
}

Answer 3

The CBAdvertisementDataServiceUUIDsKey value passed to startAdvertising should be an array of CBUUID objects but you are passing a single CBUUID
let advertisingData = [CBAdvertisementDataLocalNameKey:"my-peripheral", CBAdvertisementDataServiceUUIDsKey: [uuid]]