ios - 首次运行时未调用 didUpdateLocations

Question

我的应用程序中的定位服务在您第一次运行时无法正常工作。第二次，以及之后的任何时候，它都可以正常工作。这是我的代码:

- (void)viewDidLoad {
[super viewDidLoad];

locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.allowsBackgroundLocationUpdates = true;
[locationManager requestAlwaysAuthorization];

if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusAuthorizedAlways ||
    [CLLocationManager authorizationStatus] == kCLAuthorizationStatusAuthorizedWhenInUse) {
    [locationManager startUpdatingLocation];
}
}

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations
{
latitude = locationManager.location.coordinate.latitude;
longitude = locationManager.location.coordinate.longitude;
NSLog(@"New Location. Lat: %f, Long: %f", latitude, longitude);
}

Answer 1

问题是 requestAlwaysAuthorization异步运行，因此您的代码检查授权并调用 startUpdatingLocation将在用户授权之前执行。这就是为什么它会第二次起作用，因为他们第一次给予了许可。你可以做的是实现locationManager:didChangeAuthorizationStatus:代表并调用startUpdatingLocation也在那里(如果状态更改为授权)。

来自 Apple docs

When the current authorization status is kCLAuthorizationStatusNotDetermined, this method runs asynchronously and prompts the user to grant permission to the app to use location services