Question

我已阅读并按照How do I zoom an MKMapView to the users current location without CLLocationManager?

上的说明操作

然而，虽然我确实得到了当前的用户位置，但我无法让地图在视觉上居中。

例如，在viewDidLoad函数中，如何使地图围绕用户已知位置进行可视化居中？我已粘贴下面的CurrentLocation代码（请参阅viewDidLoad中的XXX注释


#import "MapViewController.h"
#import "PlacemarkViewController.h"

@implementation MapViewController

@synthesize mapView, reverseGeocoder, getAddressButton;

- (void)viewDidLoad
{
    [super viewDidLoad];

    // XXX HERE: How can I cause self.mapView to actually recenter itself at self.mapview.userLocation.location?


    mapView.showsUserLocation = YES;
}

- (void)viewDidUnload
{
    self.mapView = nil;
    self.getAddressButton = nil;
}

- (void)dealloc
{
    [reverseGeocoder release];
    [mapView release];
    [getAddressButton release];

    [super dealloc];
}

- (IBAction)reverseGeocodeCurrentLocation
{
    self.reverseGeocoder =
        [[[MKReverseGeocoder alloc] initWithCoordinate:mapView.userLocation.location.coordinate] autorelease];
    reverseGeocoder.delegate = self;
    [reverseGeocoder start];
}

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error
{
    NSString *errorMessage = [error localizedDescription];
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Cannot obtain address."
                                                        message:errorMessage
                                                       delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
    [alertView show];
    [alertView release];
}

- (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark *)placemark
{
    PlacemarkViewController *placemarkViewController =
        [[PlacemarkViewController alloc] initWithNibName:@"PlacemarkViewController" bundle:nil];
    placemarkViewController.placemark = placemark;
    [self presentModalViewController:placemarkViewController animated:YES];
}

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
    // we have received our current location, so enable the "Get Current Address" button
    [getAddressButton setEnabled:YES];
}

@end

Answer 1

看起来您可以简单地使用MKMapView class的centerCoordinate属性 - 文档说：

更改此属性中的值会使地图在新坐标上居中，而不会更改当前缩放级别。它还会更新region属性中的值，以反映新的中心坐标和维持当前缩放级别所需的新跨度值。

基本上，你只是这样做：

self.mapView.centerCoordinate = self.mapView.userLocation.location.coordinate;

当用户位置已知或更改时，如何以可视方式居中显示MKMapView地图？

1 个答案: