如何在 Swift 中使用 CoreBluetooth 和completionHandler 解析 BLE 通知？

Question

我必须在用 Swift UI 编写的简单项目中添加 BLE 设备支持。

型号：手机发送请求（.withoutResponse）<->BLE 设备通过 BLE 通知应答。

由于我不是专业的 Swift 程序员，我的主要问题是如何通过代码解析这些通知以执行另一个函数（例如，如果响应正常，则将设备参数保存到 CoreData/UserDefaults）。

func saveDevice(identifier: UUID, name: String, type: Int) { 
        
        writeToIdentifier(identifier: identifier, data: Request.deviceSave(name: name, type: type))

        //!
        CoreDataModel.shared.saveDevice(uuid: identifier, name: name, type: Int16(type)) // I'd like to complete/or not this function when we get notification from device
    }

func writeToIdentifier(identifier: UUID, data: Data) {
        
        print("Writing to identifier: ", identifier)
        if let index = self.devices.firstIndex(where: {$0.identifier == identifier}) {
            let peripheral = self.devices[index].peripheral
            let characteristic = peripheral.services?.first?.characteristics?[1]
            peripheral.writeValue(data, for: characteristic!, type: .withoutResponse)
        }
    }

func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
        if let value = characteristic.value {
            parseResponse(data: value, identifier: peripheral.identifier)
        }
    }

func parseResponse(data: Data, identifier: UUID) {
        
        let method: UInt8 = data.first!
        
        switch (method) {
        case 1:                             
            print("Method: DEVICE SAVE")
            if (data[5] == 1) {              // Here we get response and only now we'd like to save the device to CoreData
                print("Is configured: true")
            } else {
                print("Is configured: false")
            }
        }
} 

我已经开始学习 swift 异步编程，但我不得不向你寻求帮助。

Answer 1

如果您要求Peripheral通信时解析数据。

这就是你尝试一下的方法。

func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor   characteristic: CBCharacteristic, error: Error?) {
    if let error = error {
        print("ERROR didUpdateValue \(error)")            
        return
    }
 //BLE_Characteristic_uuid > Your BLE Char UUID
    if characteristic.uuid == CBUUID(string: BLE_Characteristic_uuid) {
        guard let value = characteristic.value else { return }
        
        let content = String(data: value, encoding:.utf8)?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""//.filter { !" \n\t\r".contains($0) } ?? ""
        print("Value Received:-->",content )
        if let i = content.utf8.firstIndex(where: { $0 >= 32 }) {
            let asciiPrefix = String(content.utf8[..<i])!
            print(asciiPrefix)
            
        }else{
            return
        }
    }
}

32 的 ASCII 值对应于空格字符 (' ')。因此，表达式 content.utf8.firstIndex(where: { $0 >= 32 }) 返回内容字符串的 UTF-8 表示形式中第一个非控制字符的索引。但是您可以根据您的要求控制它。

它也会忽略\u{01}