Core Bluetooth Swift获取设备名称

Question

我正在研究核心蓝牙框架，我做了一个关于它的学习测试项目：

class ViewController: UIViewController,CBCentralManagerDelegate,CBPeripheralDelegate {

    var centralManager: CBCentralManager = CBCentralManager()
    var peripheral: CBPeripheral? = nil

    override func viewDidLoad()
    {
        super.viewDidLoad()
        centralManager = CBCentralManager(delegate: self, queue: nil)
    }

    override func didReceiveMemoryWarning()
    {
        super.didReceiveMemoryWarning()

    }

    func centralManagerDidUpdateState(_ central: CBCentralManager)
    {
        central.scanForPeripherals(withServices: nil, options: nil)
    }

    @available(ios 5.0, *)
    public func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber)
    {
        let device = (advertisementData as NSDictionary)
            .object(forKey: CBAdvertisementDataLocalNameKey)
            as? NSString

        let isMyIphone = device?.contains("iPhone")

    }
}

为了开始我想看到我周围的蓝牙名称，因此我有2个iPhone。一个我用来执行这个'app'进行扫描，我想看到另一个iPhone的名称（蓝牙设置名称是'iPhone'），但是当我开始扫描方法'didDiscover'被调用但设备常数是零。为什么？我错了什么？