使用操作获取 CLLocation 数据

Question

import Foundation
import CoreLocation

class LocationOperation: Operation, CLLocationManagerDelegate {

  // MARK: Properties
  private var manager: CLLocationManager?
  private let handler: (CLLocation) -> Void

  // MARK: Initialization
  init(locationHandler: @escaping (CLLocation) -> Void) {
    self.handler = locationHandler
    super.init()
  }

  // MARK: Main
  override func main() {
    DispatchQueue.main.async {
      let manager = CLLocationManager()
      manager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
      manager.delegate = self
      manager.startUpdatingLocation()
    }
  }

  override func cancel() {
    DispatchQueue.main.async {
      self.stopLocationUpdates()
      super.cancel()
    }
  }

  private func stopLocationUpdates() {
    manager?.stopUpdatingLocation()
    manager = nil
  }

  // MARK: CLLocationManagerDelegate
  func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    guard let location = locations.last,
      location.horizontalAccuracy <= manager.desiredAccuracy else {
        return
    }
    stopLocationUpdates()
    handler(location)
  }

  func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
    stopLocationUpdates()
    print("Failure to find location") // handle this eventually
    self.cancel()
  }
}

main 在 CLLocationManager 有机会获取位置并将其传递给传入的处理程序之前完成执行。第一个尝试的解决方案是覆盖 isExecuting 属性并在我调用 (_:didUpdateLocations) 中的 handler(location) 后手动将其设置为 true，但这是只读的属性。这个 link 提供了一种方法来做到这一点，但我不确定实现。 如何在将位置传递给处理程序之前阻止操作完成？。谢谢！

Answer 1

两个严重的问题：

manager 在 main() 中本地声明并在 main() 退出后销毁。

替换
```
private var manager: CLLocationManager?
```
和
```
private let manager = CLLocationManager()
```
并删除局部变量

~~let manager = CLLocationManager()~~

在 main() 中。我什至更喜欢 lazy 属性。
您必须按照描述使用异步 Operation

使用操作获取 CLLocation 数据

Get CLLocation data using an Operation

swift

cllocationmanager

operation