iOS蓝牙断线如何自动重连？CoreBluetooth开发实战教程

核心流程与代码实现

环境配置

import CoreBluetooth
class BluetoothManager: NSObject, CBCentralManagerDelegate {
    var centralManager: CBCentralManager!
    var connectedPeripheral: CBPeripheral?
    override init() {
        super.init()
        centralManager = CBCentralManager(delegate: self, queue: nil)
    }
    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        switch central.state {
        case .poweredOn:
            scanForDevices()
        case .poweredOff:
            print("蓝牙未开启")
        default: break
        }
    }
}

设备扫描与过滤

func scanForDevices() {
    // 筛选心率监测设备
    let heartRateServiceUUID = CBUUID(string: "180D")
    centralManager.scanForPeripherals(withServices: [heartRateServiceUUID], 
                                     options: [CBCentralManagerScanOptionAllowDuplicatesKey: false])
}
func centralManager(_ central: CBCentralManager, 
                   didDiscover peripheral: CBPeripheral,
                   advertisementData: [String : Any], 
                   rssi RSSI: NSNumber) {
    guard let name = peripheral.name, name.contains("HRM") else { return }
    connectedPeripheral = peripheral
    centralManager.connect(peripheral, options: nil)
}

设备连接与服务发现

func centralManager(_ central: CBCentralManager, 
                   didConnect peripheral: CBPeripheral) {
    peripheral.delegate = self
    peripheral.discoverServices(nil) // 发现所有服务
}
// CBPeripheralDelegate
func peripheral(_ peripheral: CBPeripheral, 
               didDiscoverServices error: Error?) {
    guard let services = peripheral.services else { return }
    for service in services {
        print("发现服务: (service.uuid)")
        peripheral.discoverCharacteristics(nil, for: service)
    }
}

数据传输处理

func peripheral(_ peripheral: CBPeripheral,
               didDiscoverCharacteristicsFor service: CBService,
               error: Error?) {
    guard let characteristics = service.characteristics else { return }
    for characteristic in characteristics {
        // 订阅心率测量特征
        if characteristic.uuid == CBUUID(string: "2A37") {
            peripheral.setNotifyValue(true, for: characteristic)
        }
        // 读取设备信息
        if characteristic.uuid == CBUUID(string: "2A29") {
            peripheral.readValue(for: characteristic)
        }
    }
}
func peripheral(_ peripheral: CBPeripheral,
               didUpdateValueFor characteristic: CBCharacteristic,
               error: Error?) {
    guard let data = characteristic.value else { return }
    switch characteristic.uuid {
    case CBUUID(string: "2A37"):
        let heartRate = parseHeartRate(data)
        print("当前心率: (heartRate)bpm")
    case CBUUID(string: "2A29"):
        let model = String(data: data, encoding: .utf8)
        print("设备型号: (model ?? "")")
    default: break
    }
}

关键问题解决方案

后台运行支持
在Info.plist中添加：

<key>UIBackgroundModes</key>
<array>
    <string>bluetooth-central</string>
</array>

连接优化策略

// 断线自动重连
func centralManager(_ central: CBCentralManager,
                   didDisconnectPeripheral peripheral: CBPeripheral,
                   error: Error?) {
    if let peripheral = connectedPeripheral {
        centralManager.connect(peripheral, options: nil)
    }
}
// 连接超时处理
DispatchQueue.main.asyncAfter(deadline: .now() + 10.0) {
    if self.connectedPeripheral?.state != .connected {
        self.centralManager.cancelPeripheralConnection(peripheral)
    }
}

数据分包处理

// 处理长数据分包
var packetBuffer = Data()
func peripheral(_ peripheral: CBPeripheral,
               didUpdateValueFor characteristic: CBCharacteristic,
               error: Error?) {
    guard let data = characteristic.value else { return }
    if characteristic.properties.contains(.notify) {
        packetBuffer.append(data)
        if !characteristic.isNotifying {
            processCompletePacket(packetBuffer)
            packetBuffer.removeAll()
        }
    }
}

安全实践建议

1. 配对加密

   // 请求配对
   peripheral.openL2CAPChannel(PSM: 31) // PSM需根据设备协议指定

2. 数据验证

   func validateChecksum(_ data: Data) -> Bool {
    var checksum: UInt8 = 0
    data.dropLast().forEach { checksum ^= $0 }
    return checksum == data.last
   }

3. 权限管理

   // 在Info.plist中配置
   <key>NSBluetoothAlwaysUsageDescription</key>
   <string>需要蓝牙权限连接健康设备</string>

性能优化技巧

1. 连接参数协商

   

   let connectionOptions: [String: Any] = [
    CBConnectPeripheralOptionNotifyOnConnectionKey: true,
    CBConnectPeripheralOptionNotifyOnDisconnectionKey: true,
    CBConnectPeripheralOptionNotifyOnNotificationKey: true
   ]
   centralManager.connect(peripheral, options: connectionOptions)

2. 动态扫描策略

   // 根据电量调整扫描间隔
   func adjustScanRate(batteryLevel: Float) {
    centralManager.stopScan()
    let interval = batteryLevel > 0.2 ? 5.0 : 30.0
    Timer.scheduledTimer(withTimeInterval: interval, repeats: true) { _ in
        self.centralManager.scanForPeripherals(withServices: nil)
    }
   }

实战经验分享

1. 设备兼容性处理

   // 双模蓝牙适配
   #if os(iOS)
   let manager = CBCentralManager(delegate: self, queue: nil)
   #elseif os(macOS)
   let manager = CBCentralManager(delegate: self, queue: nil, 
                              options: [CBCentralManagerOptionShowPowerAlertKey: true])
   #endif

2. 错误诊断代码

   func peripheral(_ peripheral: CBPeripheral, 
               didWriteValueFor characteristic: CBCharacteristic, 
               error: Error?) {
    if let error = error as? CBError {
        switch error.code {
        case .writeNotPermitted:
            print("写入权限被拒绝")
        case .invalidHandle:
            print("无效的特征句柄")
        default:
            print("未知错误: (error.localizedDescription)")
        }
    }
   }

测试提示：使用Apple的Bluetooth Explorer工具（需下载Apple附加工具）模拟BLE设备进行全流程测试。