Question

这是我的目标：每次打开包含MapView的视图，然后停止位置以节省电池时，我必须在地图上显示用户位置及其地址。到目前为止，我可以做到，但如果用户移动到另一个区域并进入视图（离开后），位置不会改变。

这是我的代码：

- (void)viewDidLoad
{
    mapView.mapType = MKMapTypeStandard;
    self.locationManager.delegate = self;
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    [super viewDidLoad];

}

- (void)viewDidAppear:(BOOL)animated{

    if(!self.locationManager){
        self.locationManager = [[CLLocationManager alloc] init];
    }

    [self.locationManager startUpdatingLocation];

}

-(void)viewDidDisappear:(BOOL)animated{

    self.locationManager = nil;
}

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

    MKCoordinateRegion viewRegion =
    MKCoordinateRegionMakeWithDistance(newLocation.coordinate, 2000, 2000);
    MKCoordinateRegion adjustedRegion = [mapView regionThatFits:viewRegion];
    [mapView setRegion:adjustedRegion animated:YES];

    [manager stopUpdatingLocation];

    MKReverseGeocoder *geocoder = [[MKReverseGeocoder alloc]
                                   initWithCoordinate:newLocation.coordinate];
    geocoder.delegate = self;
    [geocoder start];    
}

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark *)placemark {

    MapLocation *annotation = [[MapLocation alloc] init];
    annotation.streetAddress = placemark.thoroughfare;
    annotation.city = placemark.locality;
    annotation.state = placemark.administrativeArea;
    annotation.zip = placemark.postalCode;
    annotation.coordinate = geocoder.coordinate;

    [mapView addAnnotation:annotation];

    geocoder.delegate = nil;
}

- (void)openCallout:(id<MKAnnotation>)annotation {

    [mapView selectAnnotation:annotation animated:YES];
}

- (MKAnnotationView *) mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>) annotation {
    static NSString *placemarkIdentifier = @"Map Location Identifier";
    if ([annotation isKindOfClass:[MapLocation class]]) {
        MKPinAnnotationView *annotationView = (MKPinAnnotationView *)[theMapView dequeueReusableAnnotationViewWithIdentifier:placemarkIdentifier];
        if (annotationView == nil)  {
            annotationView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:placemarkIdentifier];
        }
        else{
            annotationView.annotation = annotation;
        }
        annotationView.enabled = YES;
        annotationView.canShowCallout = YES;
        annotationView.image = [UIImage imageNamed:@"rescue"];
        [self performSelector:@selector(openCallout:) withObject:annotation afterDelay:0.5];

        return annotationView;

    }
    return nil;
}

我在另一个视图上有一个CLLocationManager，它获取没有地图的用户位置（这里的位置工作得很好）。如果在该视图上启动该位置并返回到包含地图的视图，则会更新该视图。为什么？

任何想法？

Answer 1

- (void)loadView {
    MKMapView *mv = [[MKMapView alloc]init];
    mapView.showsUserLocation=YES;
    mv.delegate=self;
}
- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation{
    [mapView setCenterCoordinate:mapView.userLocation.location.coordinate animated:YES];
    mapView.showsUserLocation=NO;
}

Answer 2

好在地图上显示

MKMapView *mv = [[MKMapView alloc]init];
CLLocationCoordinate2D c = CLLocationCoordinate2DMake(locationManager.location.coordinate.latitude, locationManager.location.coordinate.longitude);
[mv setCenterCoordinate:c animated:YES];

并停止更新

[locationManager stopUpdatingLocation];

在地图上显示用户位置并停止位置

2 个答案: