ios - startMonitoring 不适用于 "WhenInUseAuthorization"权限

Question

我正在做一个项目，但是某个区域的监控功能不起作用。

所以我创建了一个非常简单的项目来测试这个功能。我发现了一个有趣的情况。

代码如下:

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController, CLLocationManagerDelegate {
    @IBOutlet weak var map: MKMapView!

    let clMan = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()

        map.showsUserLocation = true

        clMan.requestWhenInUseAuthorization()
        clMan.delegate = self
        clMan.startUpdatingLocation()
        clMan.startMonitoring(for:CLCircularRegion(center: CLLocationCoordinate2D.init(latitude:  51.5100888, longitude: -0.134575500000008), radius: 1000, identifier: "Picca")
)

    }


    func locationManager(_ manager: CLLocationManager, didEnterRegion region: CLRegion) {
        print(region)
    }
} 

奇怪的是如果我改变

requestWhenInUseAuthorization() 与requestAlwaysAuthorization() 我的代码有效!

我将 Piccadilly Circus 设置为使用模拟位置进行测试。去伦敦之前定了另一个城市，后来又定了伦敦!

Answer 1

来自documentation :

If the user grants “when-in-use” authorization to your app, your app can start most (but not all) location services while it is in the foreground. (Apps cannot use any services that automatically relaunch the app, such as region monitoring or the significant location change service.

更多来自 documentation :

In iOS, registered regions persist between launches of your app. If a region boundary crossing occurs while your iOS app is not running, the system automatically wakes it up (or relaunches it) in the background so that it can process the event.