调用requestAuthorizationWhenInUse()后LocationManager仍卡在.notDetermined状态

我正在尝试用Swift、SwiftUI和CoreLocation开发第一个应用，以下是我的代码：

LocationManager 可观察类 #

import Foundation
import CoreLocation
import SwiftUI

@Observable class LocationManager: NSObject, CLLocationManagerDelegate {
    let manager: CLLocationManager
    
    var lastLocation: CLLocation? {
        manager.location
    }
    
    override init() {
        manager = CLLocationManager()
        super.init()
        
        manager.delegate = self
        manager.desiredAccuracy = kCLLocationAccuracyBest
    }
}

extension LocationManager {
    
    private func redirectToSettings() {
        if let url = URL(string: UIApplication.openSettingsURLString) {
            UIApplication.shared.open(url)
        }
    }
    
    func requestWhenInUseAuthorization() {
        return manager.requestWhenInUseAuthorization()
    }
    
    private func handleAuthorizationStatusChange(_ status: CLAuthorizationStatus) {
        switch status {
        case .notDetermined:
            print("not determined")
            requestWhenInUseAuthorization()
        case .authorizedWhenInUse:
            print("yes")
            manager.requestAlwaysAuthorization()
            return manager.startUpdatingLocation()
        case .authorizedAlways:
            return manager.startUpdatingLocation()
        case .denied, .restricted:
            return redirectToSettings()
        @unknown default:
            print("Unknown authorization status")
        }
    }
    
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print("\(error)")
    }
    
    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        handleAuthorizationStatusChange(status)
    }
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        print(locations)
    }
}

FirstView 视图代码 #

import SwiftUI

struct FirstView: View {
    @Environment(LocationManager.self) var locationManager
    
    var body: some View {
        if let clLocation = locationManager.lastLocation {
            Text(clLocation.description)
        } else {
            Text("No location")
        }
    }
}

#Preview {
    FirstView()
}

ContentView 代码 #

struct ContentView: View {
    var body: some View {
        TabView {
            FirstView()
                .tabItem {
                    Label("Explore", systemImage: "globe")
                }
            SecondView()
                .tabItem {
                    Label("Tortoise", systemImage: "tortoise")
                }
            ThirdView()
                .tabItem {
                    Label("Tortoise", systemImage: "tortoise")
                }
        }
    }
}

#Preview {
    ContentView()
}

遇到的问题 #

授权回调触发时，状态是.notDetermined，于是调用requestWhenInUseAuthorization()请求授权，但用户没有收到授权弹窗，状态也没变化，回调不会再次触发。设备设置里的定位服务已经开启，请问可能是什么原因？

• Info.plist 缺少权限描述
  CoreLocation 请求授权时，必须在Info.plist中添加对应的权限说明，否则系统不会弹出授权弹窗。
  若请求"When In Use"授权，需添加NSLocationWhenInUseUsageDescription（字符串类型），填写向用户说明权限用途的文案，比如"需要获取你的位置来提供相关服务"。
  如果后续要请求"Always"授权，还需添加NSLocationAlwaysAndWhenInUseUsageDescription（iOS 11及以上）。

• 未主动触发授权请求
  当前LocationManager初始化后仅设置了代理，未主动发起授权请求。虽然didChangeAuthorization回调首次触发时会调用授权方法，但如果系统因缺少权限描述等原因不响应，就会卡住。可以在视图加载时主动触发，比如给FirstView添加onAppear：

  struct FirstView: View {
      @Environment(LocationManager.self) var locationManager
      
      var body: some View {
          // ... 原有视图代码
          .onAppear {
              locationManager.requestWhenInUseAuthorization()
          }
      }
  }
  

  同时要确保在App入口注入LocationManager环境对象：

  @main
  struct YourApp: App {
      var body: some Scene {
          WindowGroup {
              ContentView()
                  .environment(LocationManager())
          }
      }
  }
  

• 授权逻辑的循环误区
  当状态为.notDetermined时调用requestWhenInUseAuthorization()，这个操作本身不会再次触发didChangeAuthorization回调——只有用户在授权弹窗中做出选择后，回调才会再次触发。如果弹窗因为权限描述缺失不出现，状态就会一直停留在.notDetermined，导致流程卡住。所以优先解决权限描述问题是关键。

• 预览环境的限制
  FirstView的预览中没有注入LocationManager环境对象，预览时无法正常测试授权流程，但真机或模拟器运行时的问题与预览无关，只需确保正式运行时环境对象已正确注入即可。

内容的提问来源于stack exchange，提问作者explosivemango