ios - swift3 中的数据到 Int/String

Question

我正在使用 BLE 设备。设备正在发送特定 UUID 中的值。
这是我将 Data 转换为 Int 或 String 以便显示的代码。

...
else if characteristic.uuid == CBUUID(string: UUID_CHANGEIN_BATTERY_LEVEL) {
//            let battery = UInt32(bigEndian: ((characteristic.value?.withUnsafeBytes { $0.pointee }) ?? 0))
            let array : [UInt8] = [0, 0, 0]
            var data = Data(bytes: array)
            if characteristic.value != nil {
                data.append(characteristic.value!)
            }
            let battery = UInt32(bigEndian: ((data.withUnsafeBytes { $0.pointee }) ?? 0))
            print("battery level changed\nNew level is \(getInt(fromData: characteristic.value!, start: 0))!")
//            lblBattery.text = (String(data: characteristic.value!, encoding: String.Encoding.utf8) ?? "0") + "%"
            lblBattery.text = "\(getInt(fromData: characteristic.value!, start: 0))%"

        }
...
func getInt(fromData data: Data, start: Int) -> Int32 {
        let intBits = data.withUnsafeBytes({(bytePointer: UnsafePointer<UInt8>) -> Int32 in
            bytePointer.advanced(by: start).withMemoryRebound(to: Int32.self, capacity: 4) { pointer in
                return pointer.pointee
            }
        })
        return Int32(bigEndian: intBits)
//        return Int32(littleEndian: intBits)
    }

我已检查 BLE 扫描仪 iOS 应用程序，该应用程序显示 0x2b01 作为值，并且还显示 43 作为电池百分比。
我写了 3-4 种代码，如上面所示。但他们都没有给我 43 作为值。

请帮助我找出哪里做错了或者我缺少哪些内容来满足我的要求。

Answer 1

swift 3

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

   let value = [UInt8](characteristic.value!)

   print("Battery ", value[0], "%")
}