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我有一张地图，当按下按钮时，它会显示用户的位置并放大。但是，一旦按下该按钮，您就无法在地图上滚动，它会一直快速回到用户的位置。我需要添加/更改什么？谢谢。

// Set action for when the refreh button is pressed

-(IBAction)refreshMapView:(id)sender {

[self refreshMap];
}

// Set action for when the show user location button is pressed

-(IBAction)getlocation {

mapView.showsUserLocation = YES;
[self.mapView.userLocation addObserver:self forKeyPath:@"location" options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld) context:nil];

}

// Display segment button to change map views

-(IBAction)changeSeg:(id)sender {

if (segment.selectedSegmentIndex == 0) {
    mapView.mapType = MKMapTypeStandard;
}
if (segment.selectedSegmentIndex == 1) {
    mapView.mapType = MKMapTypeSatellite;
}
if (segment.selectedSegmentIndex == 2) {
    mapView.mapType = MKMapTypeHybrid;
}
}

// Listen to change in the userLocation

-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{

MKCoordinateRegion region;
region.center = self.mapView.userLocation.coordinate;

MKCoordinateSpan span;
span.latitudeDelta  = 0.2; // Change these values to change the zoom
span.longitudeDelta = 0.2;
region.span = span;

[self.mapView setRegion:region animated:YES];
}   

// Load everying when map tab is accessed

-(void)viewDidLoad {

// Load mapView from MKMapKit

[super viewDidLoad];

mapView = [[MKMapView alloc] initWithFrame:self.view.bounds];
[self.view insertSubview:mapView atIndex:0];

[mapView setMapType:MKMapTypeStandard];
[mapView setZoomEnabled:YES];
[mapView setScrollEnabled:YES];
[mapView setDelegate:self];

// Display WCCCA HQ annotation pin.

MKCoordinateRegion WCCCA = { {0.0, 0.0} , {0.0, 0.0} };
WCCCA.center.latitude = 45.53540820864449;
WCCCA.center.longitude = -122.86178648471832;
WCCCA.span.longitudeDelta = 0.02f;
WCCCA.span.latitudeDelta = 0.02f;
[mapView setRegion:WCCCA animated:YES];

Annotation *ann1 = [[Annotation alloc] init];
ann1.title = @"WCCCA";
ann1.subtitle = @"Washington County Consolidated Communications Agency";
ann1.coordinate = WCCCA.center;
[mapView addAnnotation: ann1];

// Display call annotations based on xml parser data.

NSArray *callsArray = [xmlParser calls];

for (JointCAD *call in callsArray) {
    NSString *callnumber = [call.callnumber stringByAppendingFormat:@". "];
    NSString *callandnumber = [callnumber stringByAppendingString:call.currentCallType];
    Annotation *ann = [[Annotation alloc] init];
    ann.title = callandnumber;
    ann.subtitle = [call location];
    ann.coordinate = CLLocationCoordinate2DMake([call.latitude doubleValue], [call.longitude doubleValue]);
    [mapView addAnnotation:ann]; }

}

// Annotation details.

-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation {

// Set user location annotation to blue point instead of red pin

if ([annotation isKindOfClass:[MKUserLocation class]])
    return nil;

MKPinAnnotationView *MyPin=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"current"];
MyPin.pinColor = MKPinAnnotationColorRed;

UIButton *advertButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
[advertButton addTarget:self action:@selector(button:) forControlEvents:UIControlEventTouchUpInside];

// MyPin.rightCalloutAccessoryView = advertButton;
MyPin.draggable = NO;
MyPin.highlighted = YES;
MyPin.animatesDrop= TRUE;
MyPin.canShowCallout = YES;

return MyPin;
}

 // Set default view when accessing Maps tab.

- (void)viewWillAppear:(BOOL)animated {

[super viewWillAppear:animated];

CLLocationCoordinate2D coord = {.latitude =  45.422424, .longitude =  -122.76};
MKCoordinateSpan span = {.latitudeDelta =  0.60, .longitudeDelta =  0.60};
MKCoordinateRegion region = {coord, span};
[mapView setRegion:region];
}

@end
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1 回答 1

3

在getlocation您设置并开始观察用户位置变化的方法showsUserLocation中，使用.YESaddObserver

因此，只要用户位置发生变化（设备移动或获得更新位置时），该observeValueForKeyPath方法就会触发。在该方法中，您将地图的区域重置为以用户位置为中心。

在用户平移或缩放其他位置后，如果发生另一个用户位置更改，则该方法将再次触发并且地图将返回到用户位置。

在您的情况下，最简单的解决方法是在您第一次缩放到用户位置后立即停止观察。在observeValueForKeyPath方法中，在该setRegion行之后，添加：

[self.mapView.userLocation removeObserver:self forKeyPath:@"location"];


请注意，从 iOS 4.0 开始，您不需要使用 KVO（所有 addObserver 的东西）来观察用户位置的变化。相反，您可以使用didUpdateUserLocation委托方法。

从 iOS 5.0 开始，缩放到用户位置的另一个选项是将地图视图设置userTrackingMode为MKUserTrackingModeFollow或MKUserTrackingModeFollowWithHeading。这样，您不必手动设置区域。地图将缩放到用户并跟随用户，但仍让用户自由平移或缩放。

于 2012-09-01T01:45:52.170 回答