一段时间后设备断开连接且无法获取特征

Question

我知道提到的断开连接错误在堆栈上被问了很多次，但接受的答案并不是问题的实际解决方案

我正在尝试将 MI Band 3 与我的 swift 应用程序连接。连接成功，但一段时间后自动断开

Error:  Error Domain=CBErrorDomain Code=7 "The specified device has disconnected from us." UserInfo={NSLocalizedDescription=The specified device has disconnected from us

我的应用需求：我需要从Apple Watch、Fitbit和小米智能手表获取心率和步行距离

我尝试在多个设备上连接相同的 MI Band，结果是相同的。但那个特定的 MI 乐队与他们自己的应用程序完美配合

--> Connect Device - Kept reference of connected Device
    func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
        print("Connected With Peripheral: \(peripheral)")
        selectedPeripheral=peripheral
        self.delegate?.scannedPeripherals(Is: peripheral)

        /// Discover Services Provided By Device
        selectedPeripheral?.delegate=self
        selectedPeripheral?.discoverServices([heartRateServiceCBUUID])
    }

---> After Discovering services With heart Rate CBUUID
func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
        guard let characteristics = service.characteristics else { return }
        selectedPeripheral=peripheral
        for char in characteristics {
            print("Characterstics: \(char)")
            if char.properties.contains(.read) {
            }
            if char.properties.contains(.notify) {
                /// ------------- Setting Notify to true but not never call required delegates ----------------
                peripheral.setNotifyValue(true, for: char)
                print("\(char.uuid): properties contains .notify")
                peripheral.readValue(for: char)
            }
        }
    }


Calculating BPM from delegate
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
        switch characteristic.uuid {
        case bodySensorLocationCharacteristicCBUUID:
            let bodySensorLocation = bodyLocation(from: characteristic)
            print(bodySensorLocation)
        default:
            /// --------- here characteristic value is nil --------------
            let bpm = heartRate(from: characteristic)
            print("BPM: \(bpm)")
        }
    }

Answer 1

在

func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?)

尝试删除

peripheral.readValue(for: char)

并再次测试！

Answer 2

只需删除此行

peripheral.readValue(for: char)

现在一切都会按预期进行