Swift Beacon目前無法使用Swift 3.0

Question

我一直在使用Swift創建Beacon感應應用程序的指南，但自從更新Xcode並將代碼更新爲Swift 3.0後，我收到了一個致命錯誤。

通過功能我認爲有startScanning函數的問題，當它觸發時，我得到致命的錯誤消息。

在什麼可以幫助任何提示將不勝感激：

import UIKit 
import CoreLocation 

class ViewController: UIViewController, CLLocationManagerDelegate { 
@IBOutlet weak var distanceLabel: UILabel! 
var locationManager: CLLocationManager! 

override func viewDidLoad() { 
    super.viewDidLoad() 

    locationManager = CLLocationManager() 
    locationManager.delegate = self 
    locationManager.requestAlwaysAuthorization() 

    view.backgroundColor = UIColor.gray 
    print("did load") 

} 


func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) { 
    if status == CLAuthorizationStatus.authorizedAlways{ 
     print("status authorized") 
     if CLLocationManager.isMonitoringAvailable(for: CLBeaconRegion.self){ 
      print("is monitoring") 
      if CLLocationManager.isRangingAvailable() { 
       print("scanning") 
       startScanning() 

      } 
     } 
    } 
} 




func startScanning() { 
    print("start Scanning") 
    let uuid = NSUUID(uuidString: "695e5f08824c785cadc72e1dde23be04") 
    let beaconRegion = CLBeaconRegion(proximityUUID: uuid as! UUID, identifier: "MyBeacon") 

    locationManager.startMonitoring(for: beaconRegion) 
    locationManager.startRangingBeacons(in: beaconRegion) 
} 



func updateDistance(distance: CLProximity){ 

    UIView.animate(withDuration: 1) { [unowned self] in 

     switch distance { 
     case .unknown: 
      self.view.backgroundColor = UIColor.gray 
      self.distanceLabel.text = "UNKNOWN" 
      print("distance Unknown") 
     case .far: 
      self.view.backgroundColor = UIColor.blue 
      self.distanceLabel.text = "FAR" 
      print("distance Far") 
     case .near: 
      self.view.backgroundColor = UIColor.orange 
      self.distanceLabel.text = "NEAR" 
      print("distance Near") 
     case .immediate: 
      self.view.backgroundColor = UIColor.red 
      self.distanceLabel.text = "BOOM!" 
      print("distance Immediate") 
     } 
    } 
} 



func locationManager(_ manager: CLLocationManager, didRangeBeacons beacons: [CLBeacon], in region: CLBeaconRegion) { 
    if beacons.count > 0 { 
     let beacon = beacons.first! as CLBeacon 
     updateDistance(distance: beacon.proximity) 
     print("found more than one beacon") 
    } else { 
     updateDistance(distance: .unknown) 
     print("found only one beacon") 
    } 
} 



override func didReceiveMemoryWarning() { 
    super.didReceiveMemoryWarning() 
    // Dispose of any resources that can be recreated. 
} 


} 

Answer 1

的問題是，你的UUID是在錯誤的格式，所以這條線不能分析它，給變量uuid分配零：

let uuid = NSUUID(uuidString: "695e5f08824c785cadc72e1dde23be04") 

該程序然後將崩潰使用uuid as! UUID操作，因爲！如果有一個零值，將會崩潰。

要解決此問題，您需要在UUID字符串中的相應位置添加破折號。你也應該避免使用！運算符強制在Swift中打開可選變量，因爲它可能導致崩潰。試試這個：

if let uuid = NSUUID(uuidString: "695e5f08-824c-785c-adc7-2e1dde23be04") { 
    let beaconRegion = CLBeaconRegion(proximityUUID: uuid, identifier: "MyBeacon") 
    locationManager.startMonitoring(for: beaconRegion) 
    locationManager.startRangingBeacons(in: beaconRegion) 
} 
else { 
    NSLog("Invalid UUID format") 
} 

運行時檢查代碼是否沒有關閉「Invalid UUID format」路徑。