Question

我的目标是制作一个地图，其中显示用户位置带有注释和缩放，一切正常，位置有红色注释和漂亮的缩放，因为我有一个名为 PositionActuelleViewController ，这是我的代码：

PositionActuelleViewController.h ：

@interface PositionActuelleViewController : UIViewController<MKMapViewDelegate,CLLocationManagerDelegate> {


        MKMapView                   *mapView;
            MKReverseGeocoder           *geoCoder;
        MKPlacemark         *mPlacemark;
        CLLocationCoordinate2D  location;

       }
@property (nonatomic,retain)IBOutlet MKMapView *mapView;

@end

PositionActuelleViewController.m ：

    - (void)viewDidLoad {
        [super viewDidLoad];
        [mapView setShowsUserLocation:TRUE];
        [mapView setMapType:MKMapTypeStandard];
        [mapView setDelegate:self];
        [self.view insertSubview:mapView atIndex:0];
        CLLocationManager *locationManager=[[CLLocationManager alloc] init];
        [locationManager setDelegate:self];
        [locationManager setDesiredAccuracy:kCLLocationAccuracyNearestTenMeters];
        [locationManager startUpdatingLocation];
    }

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

    location = newLocation.coordinate;
    MKCoordinateRegion region;
    region.center = location;
    MKCoordinateSpan span;
    span.latitudeDelta = .005;
    span.longitudeDelta = .005;
    region.span = span;
    [mapView setRegion:region animated:TRUE];

}

我唯一的问题是即使用户缩小地图也会始终启用放大，但它会自动放大。我该如何解决这个问题？

Answer 1

如果您只想放大一次，可以添加一个名为didZoomToUserLocation的布尔值ivar。

在viewDidLoad中，在调用startUpdatingLocation之前将其初始化为NO：

didZoomToUserLocation = NO;
[locationManager startUpdatingLocation];

然后在didUpdateToLocation中，更改代码如下：

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

    location = newLocation.coordinate;

    if (didZoomToUserLocation)
        return;

    didZoomToUserLocation = YES;

    MKCoordinateRegion region;
    region.center = location;
    MKCoordinateSpan span;
    span.latitudeDelta = .005;
    span.longitudeDelta = .005;
    region.span = span;
    [mapView setRegion:region animated:TRUE];    
}

请注意，这也将停止在地图上关注用户（但仍会更新位置ivar。）

如果您想继续关注用户，但只是第一次放大，那么请改为：

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

    location = newLocation.coordinate;

    if (didZoomToUserLocation)
    {
        //just re-center map on user's location without changing zoom...
        [mapView setCenterCoordinate:newLocation.coordinate animated:YES];
    }
    else
    {
        didZoomToUserLocation = YES;

        MKCoordinateRegion region;
        region.center = location;
        MKCoordinateSpan span;
        span.latitudeDelta = .005;
        span.longitudeDelta = .005;
        region.span = span;
        [mapView setRegion:region animated:TRUE];
    }        
}

此外，在viewDidLoad中，如果在IB中创建了insertSubview，则无需在mapView上调用insertSubview。

Answer 2

您在didUpdateToLocation中的代码设置固定值的范围。每次调用该委托调用时，它都会根据这些.005跨度设置缩放。

如果您只是设置断点或登录该功能，您会发现它通常会被频繁调用。

缩放自动返回其初始缩放级别

2 个答案: