定位MKMapView以一次显示多个注释

Question

我有几个注释想要添加到我的MKMapView(它可以是0-n项,其中n通常是5左右).我可以添加注释,但我想调整地图大小以适应屏幕上的所有注释,我不知道如何做到这一点.

我一直在看,-regionThatFits:但我不太清楚如何处理它.我会发布一些代码来展示我到目前为止所拥有的内容.我认为这应该是一个通常很简单的任务,但到目前为止我对MapKit感到有些不知所措.

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

location = newLocation.coordinate;
//One location is obtained.. just zoom to that location

MKCoordinateRegion region;
region.center = location;

//Set Zoom level using Span
MKCoordinateSpan span;
span.latitudeDelta = 0.015;
span.longitudeDelta = 0.015;
region.span = span;
// Set the region here... but I want this to be a dynamic size
// Obviously this should be set after I've added my annotations
[mapView setRegion:region animated:YES];

// Test data, using these as annotations for now
NSArray *arr = [NSArray arrayWithObjects:@"one", @"two", @"three", @"four", nil];
float ex = 0.01;
for (NSString *s in arr) {
    JBAnnotation *placemark = [[JBAnnotation alloc] initWithLat:(location.latitude + ex) lon:location.longitude];
    [mapView addAnnotation:placemark];
    ex = ex + 0.005;
}
    // What do I do here?
    [mapView setRegion:[mapView regionThatFits:region] animated:YES];
}

请注意,这一切都发生在我收到位置更新时...我不知道这是否适合这样做.如果没有,哪里会更好？-viewDidLoad？

提前致谢.

Answer 1

Jim发布的链接已经死了,但我能够找到代码(我已将其添加到某个地方).希望这可以帮助.

- (void)zoomToFitMapAnnotations:(MKMapView *)mapView { 
    if ([mapView.annotations count] == 0) return; 

    CLLocationCoordinate2D topLeftCoord; 
    topLeftCoord.latitude = -90; 
    topLeftCoord.longitude = 180; 

    CLLocationCoordinate2D bottomRightCoord; 
    bottomRightCoord.latitude = 90; 
    bottomRightCoord.longitude = -180; 

    for(id<MKAnnotation> annotation in mapView.annotations) { 
        topLeftCoord.longitude = fmin(topLeftCoord.longitude, annotation.coordinate.longitude); 
        topLeftCoord.latitude = fmax(topLeftCoord.latitude, annotation.coordinate.latitude); 
        bottomRightCoord.longitude = fmax(bottomRightCoord.longitude, annotation.coordinate.longitude); 
        bottomRightCoord.latitude = fmin(bottomRightCoord.latitude, annotation.coordinate.latitude); 
    } 

    MKCoordinateRegion region; 
    region.center.latitude = topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.5; 
    region.center.longitude = topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5;      

    // Add a little extra space on the sides
    region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.1;
    region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.1; 

    region = [mapView regionThatFits:region]; 
    [mapView setRegion:region animated:YES]; 
}

Answer 2

为什么这么复杂？

MKCoordinateRegion coordinateRegionForCoordinates(CLLocationCoordinate2D *coords, NSUInteger coordCount) {
    MKMapRect r = MKMapRectNull;
    for (NSUInteger i=0; i < coordCount; ++i) {
        MKMapPoint p = MKMapPointForCoordinate(coords[i]);
        r = MKMapRectUnion(r, MKMapRectMake(p.x, p.y, 0, 0));
    }
    return MKCoordinateRegionForMapRect(r);
}

Answer 3

我做了类似的事情来缩小(或缩小)包含点注释和当前位置的区域.您可以通过循环注释来扩展它.

基本步骤是:

• 计算最小纬度/长度
  
• 计算最大纬度/经度
  
• 为这两个点创建CLLocation对象
  
• 计算点之间的距离
  
• 使用点之间的中心点和转换为度数的距离创建区域
  
• 将区域传递到MapView进行调整
  
• 使用调整的区域设置MapView区域
  

    -(IBAction)zoomOut:(id)sender {

        CLLocationCoordinate2D southWest = _newLocation.coordinate;
        CLLocationCoordinate2D northEast = southWest;

        southWest.latitude = MIN(southWest.latitude, _annotation.coordinate.latitude);
        southWest.longitude = MIN(southWest.longitude, _annotation.coordinate.longitude);

        northEast.latitude = MAX(northEast.latitude, _annotation.coordinate.latitude);
        northEast.longitude = MAX(northEast.longitude, _annotation.coordinate.longitude);

        CLLocation *locSouthWest = [[CLLocation alloc] initWithLatitude:southWest.latitude longitude:southWest.longitude];
        CLLocation *locNorthEast = [[CLLocation alloc] initWithLatitude:northEast.latitude longitude:northEast.longitude];

        // This is a diag distance (if you wanted tighter you could do NE-NW or NE-SE)
        CLLocationDistance meters = [locSouthWest getDistanceFrom:locNorthEast];

        MKCoordinateRegion region;
        region.center.latitude = (southWest.latitude + northEast.latitude) / 2.0;
        region.center.longitude = (southWest.longitude + northEast.longitude) / 2.0;
        region.span.latitudeDelta = meters / 111319.5;
        region.span.longitudeDelta = 0.0;

        _savedRegion = [_mapView regionThatFits:region];
        [_mapView setRegion:_savedRegion animated:YES];

        [locSouthWest release];
        [locNorthEast release];
    }

Answer 4

从iOS7开始,您可以使用showAnnotations:animated:

[mapView showAnnotations:annotations animated:YES];

Answer 5

我有一个不同的答案.我本来打算实现缩放到适合算法,但我认为Apple 必须有办法在没有这么多工作的情况下做我们想要的事情.使用API​​ doco很快就表明我可以使用MKPolygon来完成所需的操作:

/* this simply adds a single pin and zooms in on it nicely */
- (void) zoomToAnnotation:(MapAnnotation*)annotation {
    MKCoordinateSpan span = {0.027, 0.027};
    MKCoordinateRegion region = {[annotation coordinate], span};
    [mapView setRegion:region animated:YES];
}

/* This returns a rectangle bounding all of the pins within the supplied
   array */
- (MKMapRect) getMapRectUsingAnnotations:(NSArray*)theAnnotations {
    MKMapPoint points[[theAnnotations count]];

    for (int i = 0; i < [theAnnotations count]; i++) {
        MapAnnotation *annotation = [theAnnotations objectAtIndex:i];
        points[i] = MKMapPointForCoordinate(annotation.coordinate);
    }

    MKPolygon *poly = [MKPolygon polygonWithPoints:points count:[theAnnotations count]];

    return [poly boundingMapRect];
}

/* this adds the provided annotation to the mapview object, zooming 
   as appropriate */
- (void) addMapAnnotationToMapView:(MapAnnotation*)annotation {
    if ([annotations count] == 1) {
        // If there is only one annotation then zoom into it.
        [self zoomToAnnotation:annotation];
    } else {
        // If there are several, then the default behaviour is to show all of them
        //
        MKCoordinateRegion region = MKCoordinateRegionForMapRect([self getMapRectUsingAnnotations:annotations]);

        if (region.span.latitudeDelta < 0.027) {
            region.span.latitudeDelta = 0.027;
        }

        if (region.span.longitudeDelta < 0.027) {
            region.span.longitudeDelta = 0.027;
        }
        [mapView setRegion:region];
    }

    [mapView addAnnotation:annotation];
    [mapView selectAnnotation:annotation animated:YES];
}

希望这可以帮助.

Answer 6

你也可以这样做..

// Position the map so that all overlays and annotations are visible on screen.
MKMapRect regionToDisplay = [self mapRectForAnnotations:annotationsToDisplay];
if (!MKMapRectIsNull(regionToDisplay)) myMapView.visibleMapRect = regionToDisplay;

- (MKMapRect) mapRectForAnnotations:(NSArray*)annotationsArray
{
    MKMapRect mapRect = MKMapRectNull;

    //annotations is an array with all the annotations I want to display on the map
    for (id<MKAnnotation> annotation in annotations) { 

        MKMapPoint annotationPoint = MKMapPointForCoordinate(annotation.coordinate);
        MKMapRect pointRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0, 0);

        if (MKMapRectIsNull(mapRect)) 
        {
            mapRect = pointRect;
        } else 
        {
            mapRect = MKMapRectUnion(mapRect, pointRect);
        }
    }

     return mapRect;
}

Answer 7

根据每个人的信息和建议,我想出了以下内容.感谢大家参与本次讨论的贡献:)这将包含在包含mapView的视图中.

- (void)zoomToFitMapAnnotations { 

if ([self.mapView.annotations count] == 0) return; 

int i = 0;
MKMapPoint points[[self.mapView.annotations count]];

//build array of annotation points
for (id<MKAnnotation> annotation in [self.mapView annotations])
        points[i++] = MKMapPointForCoordinate(annotation.coordinate);

MKPolygon *poly = [MKPolygon polygonWithPoints:points count:i];

[self.mapView setRegion:MKCoordinateRegionForMapRect([poly boundingMapRect]) animated:YES]; 
}

Answer 8

使用 Swift、多边形和一些额外的填充，我使用了以下内容：

func zoomToFit() {
    var allLocations:[CLLocationCoordinate2D] = [
        CLLocationCoordinate2D(latitude: 32.768805, longitude: -117.167119),
        CLLocationCoordinate2D(latitude: 32.770480, longitude: -117.148385),
        CLLocationCoordinate2D(latitude: 32.869675, longitude: -117.212929)
    ]

    var poly:MKPolygon = MKPolygon(coordinates: &allLocations, count: allLocations.count)

    self.mapView.setVisibleMapRect(poly.boundingMapRect, edgePadding: UIEdgeInsetsMake(40.0, 40.0, 40.0, 40.0), animated: false)
}

Answer 9

在我的例子中,我开始使用CLLocation对象并为每个对象创建注释.
我只需要放置两个注释,所以我有一个简单的方法来构建点数组,但是可以很容易地扩展它以构建一个给定一组CLLocations的任意长度的数组.

这是我的实现(不需要创建MKMapPoints):

//start with a couple of locations
CLLocation *storeLocation = store.address.location.clLocation;
CLLocation *userLocation = [LBLocationController sharedController].currentLocation;

//build an array of points however you want
CLLocationCoordinate2D points[2] = {storeLocation.coordinate, userLocation.coordinate};

//the magic part
MKPolygon *poly = [MKPolygon polygonWithCoordinates:points count:2];
[self.mapView setRegion:MKCoordinateRegionForMapRect([poly boundingMapRect])];

Answer 10

以下是 Mustafa 答案的 SWIFT 等效项（已确认在 Xcode6.1、SDK 8.2 中工作）：

func zoomToFitMapAnnotations() {
    if self.annotations.count == 0 {return}

    var topLeftCoordinate = CLLocationCoordinate2D(latitude: -90, longitude: 180)
    var bottomRightCoordinate = CLLocationCoordinate2D(latitude: 90, longitude: -180)

    for object in self.annotations {
        if let annotation = object as? MKAnnotation {
            topLeftCoordinate.longitude = fmin(topLeftCoordinate.longitude, annotation.coordinate.longitude)
            topLeftCoordinate.latitude = fmax(topLeftCoordinate.latitude, annotation.coordinate.latitude)
            bottomRightCoordinate.longitude = fmax(bottomRightCoordinate.longitude, annotation.coordinate.longitude)
            bottomRightCoordinate.latitude = fmin(bottomRightCoordinate.latitude, annotation.coordinate.latitude)
        }
    }

    let center = CLLocationCoordinate2D(latitude: topLeftCoordinate.latitude - (topLeftCoordinate.latitude - bottomRightCoordinate.latitude) * 0.5, longitude: topLeftCoordinate.longitude - (topLeftCoordinate.longitude - bottomRightCoordinate.longitude) * 0.5)

    print("\ncenter:\(center.latitude) \(center.longitude)")
    // Add a little extra space on the sides
    let span = MKCoordinateSpanMake(fabs(topLeftCoordinate.latitude - bottomRightCoordinate.latitude) * 1.01, fabs(bottomRightCoordinate.longitude - topLeftCoordinate.longitude) * 1.01)
    print("\nspan:\(span.latitudeDelta) \(span.longitudeDelta)")

    var region = MKCoordinateRegion(center: center, span: span)


    region = self.regionThatFits(region)

    self.setRegion(region, animated: true)

}

Answer 11

我知道这是一个老问题，但是，如果您想显示地图上已存在的所有注释，请使用以下命令：

 mapView.showAnnotations(mapView.annotations, animated: true)