iOS 11.2.2后台定位服务失效问题技术求助

Hey there, let's dig into this CoreLocation issue you're facing on iOS 11.2.2—since it worked fine on iOS 10, the problem is almost certainly tied to iOS 11's stricter location service rules or behavior changes. Here are the key fixes and checks to try:

1. Fix the iOS 11+ Permission Request Flow #

iOS 11 overhauled how "Always" location permissions are granted, and your current code doesn't handle the updated workflow properly:

• If the user hasn't granted any permission yet, you can't directly request "Always" access first. You need to start with "When In Use" authorization, then upgrade to "Always" after the user allows it.
• Add this logic to your startLocationTracking method where you check authorization status:

  CLAuthorizationStatus authorizationStatus = [CLLocationManager authorizationStatus];
  if (authorizationStatus == kCLAuthorizationStatusNotDetermined) {
      if (@available(iOS 11.0, *)) {
          // iOS 11+ requires starting with When In Use
          [locationManager requestWhenInUseAuthorization];
      } else {
          [locationManager requestAlwaysAuthorization];
      }
  } else if (authorizationStatus == kCLAuthorizationStatusAuthorizedWhenInUse && @available(iOS 11.0, *)) {
      // Upgrade to Always permission after user allows When In Use
      [locationManager requestAlwaysAuthorization];
  }
  

• Double-check your Info.plist has all required description keys for iOS 11+:
  • NSLocationAlwaysAndWhenInUseUsageDescription (primary for iOS 11+)
  • NSLocationWhenInUseUsageDescription
  • NSLocationAlwaysUsageDescription (fallback for older iOS versions)

2. Verify Your LocationManager Singleton #

Your LocationTracker singleton might not be reinitializing correctly after the app restarts, leading to broken delegate connections:

• Ensure the singleton's sharedLocationManager method properly creates a fresh instance (or resets critical properties) on app launch:

  + (CLLocationManager *)sharedLocationManager {
      static CLLocationManager *manager = nil;
      static dispatch_once_t onceToken;
      dispatch_once(&onceToken, ^{
          manager = [[CLLocationManager alloc] init];
          // Set base properties here, but leave delegate assignment for when you use it
          manager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
          manager.distanceFilter = kCLDistanceFilterNone;
      });
      return manager;
  }
  

• Every time you call startLocationTracking, explicitly re-set the delegate to self—the old delegate reference from before the app was terminated will be invalid after a restart.

3. Remove Unnecessary Background Tasks #

When using allowsBackgroundLocationUpdates with the "Location updates" background mode enabled, you don't need to manually manage background tasks for location tracking. Your current beginNewBackgroundTask logic is redundant and might even interfere with iOS's location service prioritization:

• Delete the background task management code from applicationDidEnterBackground—iOS will handle keeping the app alive for location updates automatically if you've configured the correct background modes and permissions.

4. Fix Debug Log Visibility #

If you're manually restarting the app (not launching it via Xcode), the debugger won't automatically attach, so you won't see logs. To fix this:

• In Xcode, go to Debug > Attach to Process and select your app after manually launching it.
• Or, go to Edit Scheme > Run > Info and set "Launch" to "Wait for executable to be launched"—then manual app launches will auto-connect to the debugger.

5. Understand iOS 11's Forced Quit Behavior #

iOS 11 changed how apps behave after being force-quit:

• The system will not automatically wake your app for regular location updates (startUpdatingLocation) after a force quit. If you need location updates even after a force quit, you'll need to switch to startMonitoringSignificantLocationChanges (lower accuracy, but system-managed wake-ups).
• For regular post-restart functionality, ensure startLocationTracking is called reliably in application:didFinishLaunchingWithOptions: (not just applicationDidBecomeActive) to initialize location services as soon as the app launches.

内容的提问来源于stack exchange，提问作者Tejas R.