未调用位置管理器 didUpdateLocations答案

【问题标题】：Location manager didUpdateLocations not being called未调用位置管理器 didUpdateLocations
【发布时间】：2017-09-15 01:08:03
【问题描述】：

由于某种原因，didUpdateLocations 没有被调用，即使我将委托设置为视图控制器也是如此。在info.plist 中，我将键Privacy - Location When In Use Usage Description 设置为描述。所以我不确定我做错了什么？

import MapKit
import CoreLocation

class OptionsViewController: UIViewController, UITableViewDelegate, CLLocationManagerDelegate {
    override func viewDidLoad() {
          //Ask user for location
        locationManager = CLLocationManager()
        locationManager.requestWhenInUseAuthorization()

        //Use users current location if no starting point set
        if CLLocationManager.locationServicesEnabled() {
            let locationManager = CLLocationManager()
            locationManager.delegate = self
            locationManager.desiredAccuracy = kCLLocationAccuracyBest
            locationManager.startUpdatingLocation()
        }
    }

    override func viewDidAppear(_ animated: Bool) {
        locationManager = CLLocationManager()
        locationManager.requestWhenInUseAuthorization()
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error){
        locationManager.stopUpdatingLocation()
        print(error)
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        print("Did update location called?")
        let locValue:CLLocationCoordinate2D = manager.location!.coordinate
        print("locations = \(locValue.latitude) \(locValue.longitude)")
    }
}

【问题讨论】：

问题出在你声明 locationManager 的地方。您需要将其声明为视图控制器的属性
顺便说一句，这不是您的实际代码。 locationManager 在哪里声明？您的代码无法按原样编译
你的问题是 let locationManager = CLLocationManager() 在方法内部创建了一个新的局部变量 locationManager，一旦 viewDidLoad 方法完成，它就会不存在
如果您已经在导入 MapKit，则无需导入 CoreLocation

标签： ios swift core-location cllocationmanager

【解决方案1】：

问题来了：

  override func viewDidAppear(_ animated: Bool) {
      locationManager = CLLocationManager()
      locationManager.requestWhenInUseAuthorization()
  }

此方法将在viewDidLoad 之后调用，但是您稍后在viewDidAppear 中新创建了一个 locationManager，并且没有将其委托指向自身。这就是为什么不调用委托（自我）的方法的原因。

改进但不是最好的方法是：

class OptionsViewController: UIViewController, UITableViewDelegate, CLLocationManagerDelegate {

    let locationManager = CLLocationManager()

    override func viewDidLoad() {
        //Ask user for location
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest

        //Use users current location if no starting point set
        if CLLocationManager.locationServicesEnabled() {
            if CLLocationManager.authorizationStatus() == CLAuthorizationStatus.authorizedWhenInUse
              || CLLocationManager.authorizationStatus() == CLAuthorizationStatus.authorizedAlways {
                locationManager.startUpdatingLocation()
            }
            else{
                locationManager.requestWhenInUseAuthorization()
            }
        }
        else{
            //Alert user to open location service, bra bra bra here...
        }
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        //... nothing need to do for location here
    }

    public func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        if status == CLAuthorizationStatus.authorizedWhenInUse
          || status == CLAuthorizationStatus.authorizedAlways {
            locationManager.startUpdatingLocation()
        }
        else{
            //other procedures when location service is not permitted.
        }
    }

    //......
}

【讨论】：

locationManager = CLLocationManager() ????不是var 或let。只需抛出代码，看看会发生什么
现在是可选的，您需要更改其余代码
由于上次更新，您的更新现在有一些错误
我又更新了，现在应该没有错误了，谢谢建议，;)
我已经复制并粘贴了您的代码，但 didUpdateLocations 永远不会被调用...