在应用程序的Info.plist文件中添加一些键值对，允许BLE在应用程序被推送到后台时继续操作。

1. 添加以下键值对：

Privacy - Bluetooth Always Usage Description Privacy - Bluetooth Peripheral Usage Description

键值对的值应该是一个字符串，用于描述应用程序需要使用蓝牙的原因。

2. 在AppDelegate.swift文件中，添加以下代码：

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { // Override point for customization after application launch. UIApplication.shared.registerForRemoteNotifications() return true }

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) { let deviceTokenString = deviceToken.reduce("", {$0 + String(format: "%02X", $1)}) print("APNs device token: (deviceTokenString)") }

func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) { print(error.localizedDescription) }

3. 在ViewController.swift文件中，添加以下代码：

import CoreBluetooth

class ViewController: UIViewController, CBCentralManagerDelegate {

var centralManager: CBCentralManager!

override func viewDidLoad() {
    super.viewDidLoad()

    centralManager = CBCentralManager(delegate: self, queue: nil, options: [CBCentralManagerOptionRestoreIdentifierKey: "MyCentralManager"])
}

func centralManagerDidUpdateState(_ central: CBCentralManager) {
    switch central.state {
    case .poweredOn:
        print("Bluetooth On")
        break
    case .poweredOff:
        print("Bluetooth Off")
        break
    case .unsupported:
        print("Bluetooth Unsupported")
        break
    case .unauthorized:
        print("Bluetooth Unauthorized")
        break
    case .resetting:
        print("Bluetooth Resetting")
        break
    case .unknown:
        print("Bluetooth Unknown")
        break
    default:
        break
    }
}

}

这段代码会创建一个新的CBCentralManager对象，用于管理蓝牙的连接和断开。这个对象将使用CBCentralManagerOptionRestoreIdentifierKey选项