无法使用字符串创建NSUUID

Question

我正在使用SWIFT在iBeacon中使用iOS。当我尝试用字符串创建NSUUID时。XCode给出了一个奇怪的错误

ViewController.Type没有一个名为uuidString的成员。

但实际上，我已经声明了var uuidString，并给出了一个值

我也尝试像这样的let uuid = NSUUID(UUIDString: "")，这是可以工作的。有人知道怎么回事吗？

这是我的密码

import UIKit
import CoreLocation
import CoreBluetooth

class ViewController: UIViewController, CLLocationManagerDelegate {
    let uuidString:String! = "FDA50693-A4E2-4FB1-AFCF-C6EB07647825"
    let beaconUUID:NSUUID = NSUUID(UUIDString: uuidString)!

    let locationManager = CLLocationManager()

    let region = CLBeaconRegion(proximityUUID: beaconUUID, identifier: "Beacon")


    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager.delegate = self
        // Do any additional setup after loading the view, typically from a nib.

        if CLLocationManager.authorizationStatus() != CLAuthorizationStatus.AuthorizedWhenInUse{
            locationManager.requestWhenInUseAuthorization()
        }

        //locationManager.startRangingBeaconsInRegion(region)
    }

    func locationManager(manager: CLLocationManager!, didRangeBeacons beacons: [AnyObject]!, inRegion region: CLBeaconRegion!) {
        print(beacons)
    }
}

Answer 1

不能使用一个全局类变量来声明方法之外的另一个类变量。

我建议用region和beaconUUID中的uuidString值初始化viewDidLoad

let uuidString:String! = "FDA50693-A4E2-4FB1-AFCF-C6EB07647825"
var beaconUUID:NSUUID!

let locationManager = CLLocationManager()

var region:CLBeaconRegion! 

override func viewDidLoad() {

    beaconUUID = NSUUID(UUIDString: uuidString)
    region = CLBeaconRegion(proximityUUID: beaconUUID, identifier: "Beacon")

Answer 2

您可以使用以下代码

import UIKit
import CoreLocation
import CoreBluetooth

class ViewController: UIViewController, CLLocationManagerDelegate {


let locationManager = CLLocationManager()

let region:CLBeaconRegion = {
    let uuidString:String! = "FDA50693-A4E2-4FB1-AFCF-C6EB07647825"
    let beaconUUID:NSUUID = NSUUID(UUIDString: uuidString)!
    let result = CLBeaconRegion(proximityUUID: beaconUUID, identifier: "Beacon")
    return result
}()



override func viewDidLoad() {
    super.viewDidLoad()

    locationManager.delegate = self
    // Do any additional setup after loading the view, typically from a nib.

    if CLLocationManager.authorizationStatus() != CLAuthorizationStatus.AuthorizedWhenInUse{
        locationManager.requestWhenInUseAuthorization()
    }

    //locationManager.startRangingBeaconsInRegion(region)
}

func locationManager(manager: CLLocationManager!, didRangeBeacons beacons: [AnyObject]!, inRegion region: CLBeaconRegion!) {
    print(beacons)
}
}

不能让属性默认值取决于其他属性。

Answer 3

或者您可以在viewDidLoad()中分配两个对象类型的属性.

import UIKit
import CoreLocation
import CoreBluetooth

class ViewController: UIViewController, CLLocationManagerDelegate {
    let uuidString:String = "FDA50693-A4E2-4FB1-AFCF-C6EB07647825"
    let locationManager = CLLocationManager()

    var beaconUUID:NSUUID?
    var region:CLBeaconRegion?


    override func viewDidLoad() {
        super.viewDidLoad()

        beaconUUID = NSUUID(UUIDString: uuidString)
        region = CLBeaconRegion(proximityUUID: beaconUUID, identifier: "Beacon")

        locationManager.delegate = self
        // Do any additional setup after loading the view, typically from a nib.

        if CLLocationManager.authorizationStatus() != CLAuthorizationStatus.AuthorizedWhenInUse{
            locationManager.requestWhenInUseAuthorization()
        }

        //locationManager.startRangingBeaconsInRegion(region)
    }

    func locationManager(manager: CLLocationManager!, didRangeBeacons beacons: [AnyObject]!, inRegion region: CLBeaconRegion!) {
        print(beacons)
    }
}