iOS: Get API MISUSE: Cancelling connection for unused peripheral - ios

Question

I have a singleton class holding a CBPeripheral array. When a new device is discovered, it is added to that array. This array is used as a UITableView data source. When a table view cell is selected by the user, a connected is made to the selected CBPeripheral via fetch.
Unfortunately I get this error:
[CoreBluetooth] API MISUSE: Cancelling connection for unused peripheral <CBPeripheral: 0x1c0103e70, identifier = xxx, name = xxx, state = connecting>, Did you forget to keep a reference to it?
I searched stack overflow, there have been similar questions asked before, but all of them say the root cause is "not add peripheral to a strong reference, so iOS free it". But I have added them to an array.
Code:
class BLEManager:NSObject, CBCentralManagerDelegate, CBPeripheralDelegate {
static let sharedInstance = BLEManager()
var centralManager: CBCentralManager!
var connectedService: BLEDSPService?
var delegate: BLEDiscoveryDelegate?
var readUUIDString: String
var writeUUIDString: String
var serviceUUIDString: String
var connectedPeripheral: CBPeripheral?
var peripherals = [CBPeripheral]() {
didSet {
delegate?.peripheralDidDiscoverNewOnes()
}
}
init(serviceUUIDString: String, readUUIDString: String, writeUUIDString: String) {
self.readUUIDString = readUUIDString
self.writeUUIDString = writeUUIDString
self.serviceUUIDString = serviceUUIDString
super.init()
centralManager = CBCentralManager(delegate: self, queue: DispatchQueue.main);
}
internal func startScanning() {
let serviceUUID = CBUUID(string: serviceUUIDString)
let options = [CBCentralManagerScanOptionAllowDuplicatesKey: 0]
centralManager.scanForPeripherals(withServices: [serviceUUID], options: options)
}
func stopScanning() {
centralManager.stopScan()
delegate?.peripheralDidStopScan()
}
open func connectTo(index: Int) {
if let current = connectedPeripheral {
disconnectPeripheral(current)
}
if index < peripherals.count {
connectPeripheral(peripherals[index])
stopScan()
}
}
#objc func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
guard let name = peripheral.name?.lowercased() else {
return
}
guard (name.contains(NamesManager.shared.scanName)) else {
return
}
if !peripherals.contains(peripheral) {
peripherals.append(peripheral)
delegate?.peripheralDidDiscovered()
}
}
But if I save peripheral to a var, then connect it. it works:
var connectedPeripheral: CBPeripheral?
open func connectTo(index: Int) {
if let current = connectedPeripheral {
connectPeripheral(current)
}
stopScan()
}
#objc func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
guard let name = peripheral.name?.lowercased() else {
return
}
guard (name.contains(NamesManager.shared.scanName)) else {
return
}
if !peripherals.contains(peripheral) {
connectedPeripheral = peripheral
peripherals.append(peripheral)
stopScanning()
delegate?.peripheralDidDiscovered()
}
}