如何在 Swift 3/4 中使用相机获取位置？

Question

我遇到了这个问题，我有一个相机和一个地图视图，如果使用应用程序拍摄照片，我想要做的就是获取位置，您可以在捕获图像的那一刻访问用户的位置并扩展 UIImage 以包含位置属性，并将此位置同时保存到地图视图或 tableView 上，当使用手机的相机拍摄照片时保存图像。感谢您的任何帮助。

这是我的代码。 （相机控制器）

import UIKit

class ViewController: UIViewController, UINavigationControllerDelegate {

    @IBOutlet weak var imageView: UIImageView!
    @IBOutlet weak var resultLbl: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear(_ animated: Bool) {

    }

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


    @IBAction func CamBtn(_ sender: Any) {
        if !UIImagePickerController.isSourceTypeAvailable(.camera) {
            return
        }

        let cameraPicker = UIImagePickerController()
        cameraPicker.delegate = self
        cameraPicker.sourceType = .camera
        cameraPicker.allowsEditing = false
        MapViewController.location.requestLocation()
        guard let userLocation = MapViewController.location.location else {return}
        present(cameraPicker, animated: true)
    }


    @IBAction func LibBtn(_ sender: Any) {
        let picker = UIImagePickerController()
        picker.allowsEditing = false
        picker.delegate = self
        picker.sourceType = .photoLibrary
        present(picker, animated: true)
    }
}
   extension ViewController: UIImagePickerControllerDelegate {
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        picker.dismiss(animated: true)
        resultLbl.text = "Analyzing Image..."
        guard let image = info["UIImagePickerControllerOriginalImage"] as? UIImage else {
            return
        }

}

地图视图控制器

import Foundation
import UIKit
import MapKit

class MapViewController: UIViewController, CLLocationManagerDelegate {

    @IBOutlet weak var mapView: MKMapView!
    @IBOutlet weak var tableView: UITableView!

    let regionRadius: CLLocationDistance = 1000
    var location: CLLocationManager!
    let nearbyRequest = MKLocalSearchRequest()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        location = CLLocationManager()
        location!.delegate = self
        location.desiredAccuracy = kCLLocationAccuracyBest
        location.requestAlwaysAuthorization()
        location.startUpdatingLocation()

        if CLLocationManager.authorizationStatus() == .authorizedWhenInUse {
            location!.startUpdatingLocation()
        } else {
            location!.requestWhenInUseAuthorization()
        }
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(true)
        mapView.showsUserLocation = true
    }

    override func viewWillDisappear(_ animated: Bool) {
        mapView.showsUserLocation = false
    }


    func location(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
        switch status {
        case .notDetermined:
            print("Not Determined")
        case .restricted:
            print("Restricted")
        case .denied:
            print("Denied")
        case .authorizedAlways:
            print("AuthorizedAlways")
        case .authorizedWhenInUse:
            print("AuthorizedWhenInUse")
        location!.startUpdatingLocation()
        }  
    }

    func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
        print("Failed to initialize Map: ", error.description)
    }

}

Answer 1

如果您想在拍照时获取用户的位置，您需要在用户拍照时请求位置更新，而不仅仅是在您的其他ViewController 中开始位置更新。您可以使用CLLocationManager().requestLocation() 请求一次位置更新，但请注意这是一个异步调用，因此用户可能会在返回时完成拍照。

为缓解此问题，您可以使用PromiseKit 让您的函数仅在异步方法完成时返回，或者您可以使用CLLocationManagerDelegate func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 方法并在位置更新后立即更新图片/MapView收到了。

在MapViewController 中将var location: CLLocationManager! 更改为static var location = CLLocationManager()，相应地更新您的MapViewController 类以使用location 作为类型属性而不是隐式展开的实例属性。然后在CameraController 中更改您的函数，如下所示：

@IBAction func CamBtn(_ sender: Any) {
        if !UIImagePickerController.isSourceTypeAvailable(.camera) {
            return
        }

        let cameraPicker = UIImagePickerController()
        cameraPicker.delegate = self
        cameraPicker.sourceType = .camera
        cameraPicker.allowsEditing = false
        MapViewController.location.requestLocation()
        guard let userLocation = MapViewController.location.location else {return}
        present(cameraPicker, animated: true)
    }

这不是一个完整的示例，您仍然需要将userLocation 添加到您的图像/MapView，但您应该能够自己弄清楚这部分。此外，通过这种实现，requestLocation() 不能保证在您检查其值时返回，所以我宁愿使用PromiseKit 的CLLocationManager.promise() 函数，它只在位置更新后返回。