使用Swift在IOS中获得电池电平-1.0

Question

嗨，我是IOS开发的新手，我正在使用swift。我想以编程方式获取设备的电池电量。但总是收到-1.0

以下是我的代码 -

import UIKit

class FirstController: UIViewController{

       override func viewDidLoad() {

        super.viewDidLoad()

        UIDevice.current.isBatteryMonitoringEnabled = true

    }


    var batteyLevel : Float {

        return UIDevice.current.batteryLevel

    }


    // attached with a touchInsideUp event
    @IBAction func onButtonClick(_ sender: Any) {

    // print "Battery moniter true"
        print("Battery moniter \(UIDevice.current.isBatteryMonitoringEnabled)")

       // print "Battery -1.0"
        print("Battery \(batteyLevel)")
    }

}

请帮助查找电池电量