iOS Core Bluetooth : Getting API MISUSE Warning

You have to wait until the [-CBCentralManagerDelegate centralManagerDidUpdateState:] callback has been called. And then, verify that the state is PoweredOn before you start scanning for peripherals.

Please use the following code to solve the warning:

(You can reference to the code in https://github.com/luoxubin/BlueTooth4.0)

if (bluetoothPowerOn) {    [self.centralManager scanForPeripheralsWithServices:[serviceIDs copy] options:@{CBCentralManagerScanOptionAllowDuplicatesKey:@(NO)}];}-(void)centralManagerDidUpdateState:(CBCentralManager *)central{    switch (central.state) {        case CBManagerStatePoweredOn:        {            bluetoothPowerOn = YES;    //new code            [self start];            break;        }        default:        {                bluetoothPowerOn = NO;   //new code            [self stopScan:[NSError hardwareStatusErrorWithMessage:@"Cannot open Bluetooth, please check the setting." hardwareStatus:central.state]];                break;        }    }}

Do scan when bluetooth is poweredOn:

func centralManagerDidUpdateState(_ central: CBCentralManager) {        switch central.state {        case .unknown:            print("unknown")        case .resetting:            print("resetting")        case .unsupported:            print("unsupported")        case .unauthorized:            print("unauthorized")        case .poweredOff:            print("poweredOff")            centralManager?.stopScan()        case .poweredOn:            print("poweredOn")            centralManager?.scanForPeripherals(withServices: nil, options: nil)        }    }