multithreading - CLLocationmanager从后台线程更新

Question

我正在使用Grand Central Dispatch启动本地化请求:

- (void) findGroceriesNearMe {
    dispatch_queue_t downloadQueue = dispatch_queue_create("Groceries downloader", NULL);
    dispatch_async(downloadQueue, ^{
        CLLocationCoordinate2D userLocation = [LocationManagerController findMeWithCaller:self];
        dispatch_async(dispatch_get_main_queue(), ^{
            [self userSuccessFullyFound:userLocation];
        });
    });
    dispatch_release(downloadQueue);
}

它在我的Singleton类LocationManager Controller中调用静态方法:

+ (CLLocationCoordinate2D) findMeWithCaller: (UIViewController *) viewController {

    LocationManagerController *locationManagerController = [LocationManagerController locationManagerController];
    [locationManagerController startUpdates];

    while(![locationManagerController getterDone]){
        //mystique pour nous-- a approfondir
        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
    }

在startUpdates方法中， CLLocationManager的 LocationManagerController属性被初始化并要求输入 startUpdatingLocation。

最后，发生位置更新时的方法:

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation  fromLocation:(CLLocation *)oldLocation
{
    locationDenied = NO;
    NSLog(@"%f,%f",newLocation.coordinate.latitude,newLocation.coordinate.longitude);

    NSDate* eventDate = newLocation.timestamp;
    NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
    // On vérifie que la newLocation est récente 

    if (abs(howRecent) > 10.0) {
        return;
    }

    // Test if it's not an invalid measurement

    if (newLocation.horizontalAccuracy < 0) return;

    // Test the measurement to see if it meets the desired accuracy 

    if (newLocation.horizontalAccuracy <= manager.desiredAccuracy) 

    {
        latitude = newLocation.coordinate.latitude;
        longitude = newLocation.coordinate.longitude;
        locationDefined = YES;
        [self setterDone:YES];
    }
}

我的问题是，即使我没有要求停止，locationManager仅发送3个位置更新，然后停止发送更新。因此，基本上，我从不会退出while(![locationManagerController getterDone])循环。

顺便说一句，在尝试使用GCD实现此功能之前，它运行良好，因此我认为问题与我的多线程实现有关。

任何的想法 ？

编辑

我在控制台中没有任何错误。该程序只是继续运行，但我陷入了while循环，在第3个位置更新后没有其他 react 。

谢谢 !

Answer 1

从CLLocationManager类引用:

Configuration of your location manager object must always occur on a thread with an active run loop, such as your application’s main thread.