iphone - 当 iphone 在后台时使用 CLLocationManager 将位置发送到服务器

Question

当应用程序位于后台时，我无法发送我的位置。我正在使用 CLLocationManager 和 startMonitoringSignificantLocationChanges。 posision didUpdateToLocation 委托(delegate)方法执行一次，但不会多次执行。我尝试四处走走，但没有新位置发送到服务器。

我在 info.plist 文件中设置了“Required background modes” -> “App registers for location updates”。

有人知道哪里出了问题吗？

开始跟踪的代码:

CLLocationManager *locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = appDelegate;
[appDelegate setLocationManager:locationManager withDistanceFilter:kCLDistanceFilterNone];
[appDelegate.theLocationManager startMonitoringSignificantLocationChanges];

代码(来自 CLLocationManagerDelegate):

- (void)setLocationManager:(CLLocationManager*)locationManager withDistanceFilter:(CLLocationDistance)distanceFilter {

    // create a new manager and start checking for sig changes
    self.theLocationManager.delegate = nil;
    [theLocationManager release];

    self.theLocationManager = locationManager;
    self.theLocationManager.delegate = self;
    self.theLocationManager.distanceFilter = distanceFilter;
}


    - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {

        NSDate *newLocationTimestamp = newLocation.timestamp;
        NSDate *oldLocationTimestamp = oldLocation.timestamp;

        int locationUpdateInterval = 15;//15 sec

        if (!([newLocationTimestamp timeIntervalSinceDate:oldLocationTimestamp] < locationUpdateInterval)) {
                //NSLog(@"New Location: %@", newLocation);
                [self updateToLocation:newLocation];
        }

    }

    - (void)updateToLocation:(CLLocation *)newLocation {
        NSLog(@"update location!!");

        NSString *latitude = [NSString stringWithFormat:@"%f", [newLocation coordinate].latitude];
         NSString *longitude = [NSString stringWithFormat:@"%f", [newLocation coordinate].longitude];

        [currentUser updatePositionWithLongitude:longitude andLatitude:latitude]; 
    }

Answer 1

正如 Bill Brasky 所说，您为位置管理器设置的准确度可能不会记录您步行的距离。尝试将您的位置管理器精度设置得更高，只是为了看看是否有效，然后将其调低至精度和电池效率之间的一个令人满意的中间值。只是为了测试，一路往上走:

[appDelegate.theLocationManager setDesiredAccuracy:kCLLocationAccuracyBestForNavigation];

然后代替:

[appDelegate.theLocationManager startMonitoringSignificantLocationChanges];

尝试:

[appDelegate.theLocationManager startUpdatingLocation];