iOS issue checking if Bluetooth is ON - ios

Question

I need to check if Bluetooth is On.
I use this code:
func startDetectingBluetoothState() {
if self.centralManager == nil {
self.centralManager = CBCentralManager(delegate: self, queue: self.workingQueue, options: [CBCentralManagerOptionShowPowerAlertKey: false])
}
}
func centralManagerDidUpdateState(_ central: CBCentralManager) {
let state = central.state
DispatchQueue.main.async { [weak self] in
// notify observers about state change
self?.stateObservers.invokeDelegates { stateObserver in
stateObserver.bluetoothStateChanged()
}
}
}
I start the app on iPhone X 11.3 (Bluetooth is On in the Settings), then almost immidiatly it enters in centralManagerDidUpdateState(_ central: CBCentralManager) with state == .poweredOff. So the value is wrong. Then I turn off Bluetooth in Settings, centralManagerDidUpdateState(_ central: CBCentralManager) function is not called (because the previous state it detected was .poweredOff), then I turn on Bluetooth and centralManagerDidUpdateState(_ central: CBCentralManager) is called with .poweredOn value. Then it detects every state change properly. But if I restart the app and Bluetooth is On, it can't detect it again. If during start the Bluetooth is Off, everything is OK.
I have another device iPhone 6+ 11.2.5, where everything works as a charm :)

Answer 1

You need to implement CBCentralManagerDelegate. Below is the sample code which might help you to check the condition -
var centralManager:CBCentralManager!
in init() or viewDidLoad()
{
centralManager = CBCentralManager()
centralManager.delegate = self
}
func centralManagerDidUpdateState(_ central: CBCentralManager) {
if central.state == .poweredOn {
print("Bluetooth is connected")
}
else if central.state == .poweredOff{
print("Bluetooth is not Connected.")
}
}

Answer 2

Use this Code Working for you
var centralManager:CBCentralManager!
override func viewDidLoad()
{
super.viewDidLoad()
// This will trigger centralManagerDidUpdateState
centralManager = CBCentralManager(delegate: self, queue: nil)
}
func centralManagerDidUpdateState(_ central: CBCentralManager)
{
print("Central Manager did update state")
if (central.state == .poweredOn)
{
self.centralManager?.scanForPeripherals(withServices: nil, options: [CBCentralManagerScanOptionAllowDuplicatesKey: false])
}
else
{
// Bluetooth is unavailable for some reason
// Give feedback
var message = String()
switch central.state
{
case .unsupported:
message = "Bluetooth is unsupported"
case .unknown:
message = "Bluetooth state is unkown"
case .unauthorized:
message = "Bluetooth is unauthorized"
case .poweredOff:
message = "Bluetooth is powered off"
default:
break
}
print(message)
UIAlertView(
title: "Bluetooth unavailable",
message: message,
delegate: nil,
cancelButtonTitle: "OK")
.show()
}
}