Question

我正在尝试通过BLE发送大数据包。为此，我创建了一个特征，该特征应在数据更改时通知中央。问题在于，显然外围设备会在特性中堆叠数据，但是很明显，一旦特性达到552字节，便无法存储更多数据。

中央仅接收552个字节并调用函数didReceiveRead 3次（我一次传送200个字节，所以3次是600字节，但是只有552个字节使它通过（我认为是自iOS 10起的限制））。这段代码也只打印Unhandled Characteristic UUID: 00000000-0000-0000-0000-000000000000一次，并设法将setNotifyValue的特征复制到true。 didUpdateNotificationStateFor也仅被调用一次。

我想知道为什么我的特征是堆积数据，而不像我希望的那样一次发送200个字节。

外围设备的代码使用为：（函数块仅获取我们想要的块的大小的数据和整数，然后返回该块和减去块后的数据）

func peripheralManagerDidUpdateState(_ peripheral: CBPeripheralManager) {
    switch peripheral.state {
    case .unknown:
        print("peripheral.state is .unknown")
    case .resetting:
        print("peripheral.state is .resetting")
    case .unsupported:
        print("peripheral.state is .unsupported")
    case .unauthorized:
        print("peripheral.state is .unauthorized")
    case .poweredOff:
        print("peripheral.state is .poweredOff")
    case .poweredOn:
        print("peripheral.state is .poweredOn")

        let myService = CBMutableService(type: serviceUUID, primary: true)

        let uuid: CBUUID
        uuid = CBUUID(string: "00000000-0000-0000-0000-000000000000")
        let myCharacetristic = CBMutableCharacteristic(type: uuid, properties: [CBCharacteristicProperties.read,CBCharacteristicProperties.notify,CBCharacteristicProperties.write], value: nil, permissions: [CBAttributePermissions.readable, CBAttributePermissions.writeable])
        chara = myCharacetristic
        myService.characteristics = [myCharacetristic]
        print(myService)

        myPeripheral.add(myService)

        let advertisingData = [CBAdvertisementDataLocalNameKey:"my-peripheral", CBAdvertisementDataServiceUUIDsKey: [serviceUUID]] as [String : Any]
        myPeripheral.startAdvertising(advertisingData)
        print(advertisingData.description)
    }
}

func peripheralManager(_ peripheral: CBPeripheralManager, didReceiveRead request: CBATTRequest) {
    var max = 0
    if (data.count - 200) > 0{
        max = 200
    }else{
        max =  data.count
    }
    var subdata: Data //subdata is what I want to send
    (subdata, data) = chunck(json: data, max: max)
    print(request.value)
    request.value = subdata
    myPeripheral?.respond(to: request, withResult: CBATTError.success)
}

对于中央代码是：

public func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
    guard let characteristics = service.characteristics else { return }

    print("Characteristic:")
    for characteristic in characteristics {
        print(characteristic)
        if characteristic.properties.contains(.read) {
            print("\(characteristic.uuid): properties contains .read")
            peripheral.readValue(for: characteristic)
        }
        if characteristic.properties.contains(.notify) {
            print("\(characteristic.uuid): properties contains .notify")
            peripheral.setNotifyValue(true, for: characteristic)
            print("ok for: \(characteristic)")
        }
    }
}

public func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {

    print("Unhandled Characteristic UUID: \(characteristic.uuid)")
    print(error)
}
public func peripheral(_ peripheral: CBPeripheral, didUpdateNotificationStateFor characteristic: CBCharacteristic, error: Error?) {

    print(characteristic)
    print(characteristic.value)
}

随时询问更多代码

谢谢。

数据更新时，核心蓝牙外设不会通知中央

0 个答案: