Swift 使用委托创建 class

Question

这可能在某个地方被谈论过，但我找不到任何谈论这个的文章。我正在尝试编写一个 class 来环绕苹果的原生 CoreLocation API。我的目标是能够从 locationManager 委托中调用 LocationTrack.getDPS 之类的东西并获得 return gps 坐标。

class LocationTrack: CLLocationManagerDelegate  {

    if (CLLocationManager.locationServicesEnabled())
            {
                locationManager = CLLocationManager()
                locationManager.delegate = self
                locationManager.desiredAccuracy = kCLLocationAccuracyBest
                locationManager.requestAlwaysAuthorization()
                locationManager.startUpdatingLocation()
            }
        }

  func getDPS(completion: @escaping (result: [CLLocation]) -> () {

       //How to get below delegate response into this function?

    }

  func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

      print(locations)

}


    }

Answer 1

定义属性以捕获您的完成处理程序：

private var handler: (([CLLocation]) -> Void)?

并getDPS保存并开始更新位置：

func getDPS(_ completion: @escaping ([CLLocation]) -> Void) {
    handler = completion
    locationManager.startUpdatingLocation()
}

然后你的 didUpdateLocations 可以调用那个闭包：

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    handler?(locations)
    handler = nil
    locationManager.stopUpdatingLocation()
}

将所有这些放在一起，可能是这样的：

class LocationTrack: NSObject {
    private lazy var locationManager: CLLocationManager = {
        let locationManager = CLLocationManager()
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.requestAlwaysAuthorization()   // perhaps `requestWhenInUseAuthorization` is better?
        return locationManager
    }()

    private var handler: (([CLLocation]) -> Void)?

    func getDPS(_ completion: @escaping ([CLLocation]) -> Void) {
        handler = completion
        locationManager.startUpdatingLocation()
    }
}

extension LocationTrack: CLLocationManagerDelegate {
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        handler?(locations)
        handler = nil
        locationManager.stopUpdatingLocation()
    }
}

很明显，您可以添加自己的错误处理以及您有什么，但希望这说明了将闭包保存在属性中并在您收到委托回调时调用它的想法。

Swift 使用委托创建 class

Swift create a class using a delegate

core-location

swift