无法启动重大更改位置更新ios CLLocationManager

Question

AppDelegate.m 这是用于在从后台返回时检测应用程序，因此重要位置更改的监控将重新启动...应该这样做

if([launchOptions objectForKey:@"UIApplicationLaunchOptionsLocationKey"] != nil) {
    _restartloc = [[NSNumber alloc] initWithInt:1];
}
else {
    _restartloc = [[NSNumber alloc] initWithInt:0];
}

ViewController.h locationManager是(strong, nonatomic)属性，应该是strong，我不确定nonatomic在这种情况下

...

@interface ViewController : UIViewController <GMSMapViewDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate, CLLocationManagerDelegate>

@property (nonatomic) UIImagePickerController *imagePickerController;

#if TARGET_OS_IPHONE
@property NSMutableDictionary *completionHandlerDictionary;
@property (strong, nonatomic) AFHTTPSessionManager *manager;
@property (strong, nonatomic) CLLocationManager *locationManager;

...

viewDidLoad方法中的

ViewController.m ，我会检查应用是否来自后台，如果需要，请重新启动locationManager。似乎永远不会调用startSignificantChangeUpdates方法，我发出警报，以便在我四处走动时进行测试。我从未见过didUpdateLocations（或任何其他CLLocationMangerDelegate方法）的任何内容。

- (void)viewDidLoad {

    ...

    if(((AppDelegate *)[UIApplication sharedApplication].delegate).restartloc == [[NSNumber alloc] initWithInt:1]) {
        [_locationManager stopMonitoringSignificantLocationChanges];

        _locationManager = [[CLLocationManager alloc] init];
        _locationManager.delegate = self;

        [_locationManager startMonitoringSignificantLocationChanges];
    }

    _locationManager = [[CLLocationManager alloc] init];
    _locationManager.delegate = self;

    if([_locationManager respondsToSelector:@selector(setAllowsBackgroundLocationUpdates:)]) {
        [_locationManager setAllowsBackgroundLocationUpdates:YES];
    }

    ...
}


- (void)startSignificantChangeUpdates
{
    deviceNotFoundAlertController = [UIAlertController alertControllerWithTitle:@"START" message:@"startSignificantChangeUpdates called" preferredStyle:UIAlertControllerStyleAlert];

    [deviceNotFoundAlertController addAction:deviceNotFoundAlert];
    // Create the location manager if this object does not
    // already have one.
    if (nil == _locationManager) {
        _locationManager = [[CLLocationManager alloc] init];
        _locationManager.delegate = self;
    }

    //if ([CLLocationManager locationServicesEnabled]){

        //NSLog(@"Location Services Enabled");

    if ([CLLocationManager authorizationStatus]==kCLAuthorizationStatusNotDetermined){
        [_locationManager requestAlwaysAuthorization];
    }
    else if([CLLocationManager authorizationStatus]==kCLAuthorizationStatusRestricted || [CLLocationManager authorizationStatus]==kCLAuthorizationStatusDenied) {
        deviceNotFoundAlertController = [UIAlertController alertControllerWithTitle:@"AUTH" message:@"Not allowed by phone to proceed with location services priveleges" preferredStyle:UIAlertControllerStyleAlert];

        [deviceNotFoundAlertController addAction:deviceNotFoundAlert];
    }
    else if([CLLocationManager authorizationStatus]==kCLAuthorizationStatusAuthorizedWhenInUse) {
        [_locationManager requestAlwaysAuthorization];
    }
    else {
        //
    }

    [CLLocationManager significantLocationChangeMonitoringAvailable];
    [_locationManager startMonitoringSignificantLocationChanges];
}

-(void)locationManger:(CLLocationManager *)manager didFailWithError:(NSError *)error {
    NSLog(@"didFailWithError: %@", error);
    deviceNotFoundAlertController = [UIAlertController alertControllerWithTitle:@"LOCATION FAIL" message:@"didFailWithError" preferredStyle:UIAlertControllerStyleAlert];

    [deviceNotFoundAlertController addAction:deviceNotFoundAlert];
}

// Delegate method from the CLLocationManagerDelegate protocol.
- (void)_locationManager:(CLLocationManager *)manager
     didUpdateLocations:(NSArray *)locations {
    deviceNotFoundAlertController = [UIAlertController alertControllerWithTitle:@"LOCATION UPDATE" message:@"didUpdateLocations called" preferredStyle:UIAlertControllerStyleAlert];

    [deviceNotFoundAlertController addAction:deviceNotFoundAlert];
    // If it's a relatively recent event, turn off updates to save power.
    CLLocation* location = [locations lastObject];
    NSDate* eventDate = location.timestamp;
    NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
    if (fabs(howRecent) < 0.5) {
        // If the event is recent, do something with it.
        NSLog(@"latitude %+.6f, longitude %+.6f\n",
              location.coordinate.latitude,
              location.coordinate.longitude);
    }
}

从我所看到的，它似乎是委托的问题，方法永远不会被调用。我设置错了吗？这是我第一次使用重要的位置更改。

更新

现在这是我的设置，我仍然没有收到来自委托功能的任何警报。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]];

    _locationMgr = [[CLLocationManager alloc] init];
    [_locationMgr setDelegate:self];
    if([_locationMgr respondsToSelector:@selector(setAllowsBackgroundLocationUpdates:)])
        [_locationMgr setAllowsBackgroundLocationUpdates:YES];
    CLAuthorizationStatus authorizationStatus= [CLLocationManager authorizationStatus];

    if([launchOptions valueForKey:UIApplicationLaunchOptionsLocationKey] != nil) {
        NSLog(@"relaunching because of significant location change - restarting SLC");
        [_locationMgr startMonitoringSignificantLocationChanges];
    }
    else
    {
        if (authorizationStatus == kCLAuthorizationStatusAuthorizedAlways) {
            NSLog(@"launching with authorization to always use location - starting SLC");
            [_locationMgr startMonitoringSignificantLocationChanges];
        }
        else
        {
            NSLog(@"launching with no authorization to always use location - requesting authorization");
            if([_locationMgr respondsToSelector:@selector(requestAlwaysAuthorization)])
                [_locationMgr requestAlwaysAuthorization];
        }
    }

    if([userdefaults objectForKey:@"pfuser"] == nil) {
        NSLog(@"in delegate signup");
        SignUpController *signup = [[SignUpController alloc] init];
        [self.window setRootViewController:signup];
    }
    else {
        ViewController *map = [[ViewController alloc] init];
        [self.window setRootViewController:map];
    }
    [self.window makeKeyAndVisible];

    return YES;
}

- (void)startSignificantChangeUpdates
{
    deviceNotFoundAlertController = [UIAlertController alertControllerWithTitle:@"START" message:@"startSignificantChangeUpdates called" preferredStyle:UIAlertControllerStyleAlert];

    [deviceNotFoundAlertController addAction:deviceNotFoundAlert];
    // Create the location manager if this object does not
    // already have one.
    if (nil == _locationMgr) {
        _locationMgr = [[CLLocationManager alloc] init];
        _locationMgr.delegate = self;
    }

    [CLLocationManager significantLocationChangeMonitoringAvailable];
    [_locationMgr startMonitoringSignificantLocationChanges];
}

-(void)locationManger:(CLLocationManager *)manager didFailWithError:(NSError *)error {
    NSLog(@"didFailWithError: %@", error);
    deviceNotFoundAlertController = [UIAlertController alertControllerWithTitle:@"LOCATION FAIL" message:@"didFailWithError" preferredStyle:UIAlertControllerStyleAlert];

    [deviceNotFoundAlertController addAction:deviceNotFoundAlert];
}

// Delegate method from the CLLocationManagerDelegate protocol.
- (void)_locationManager:(CLLocationManager *)manager
      didUpdateLocations:(NSArray *)locations {
    deviceNotFoundAlertController = [UIAlertController alertControllerWithTitle:@"LOCATION UPDATE" message:@"didUpdateLocations called" preferredStyle:UIAlertControllerStyleAlert];

    [deviceNotFoundAlertController addAction:deviceNotFoundAlert];
    // If it's a relatively recent event, turn off updates to save power.
    CLLocation* location = [locations lastObject];
    NSDate* eventDate = location.timestamp;
    NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
    if (fabs(howRecent) < 15.0) {
        // If the event is recent, do something with it.
        NSLog(@"latitude %+.6f, longitude %+.6f\n",
              location.coordinate.latitude,
              location.coordinate.longitude);
    }
}