iOS MKMapView縮放以顯示所有標記

Question

我正在使用MKMapView並在地圖上繪製了幾個點。我已經使用了MKCoordinateRegion和MKCoordinateSpan圍繞其中一點實現縮放等 - 但這不是我想要的...

我正在嘗試使用類似於JavaScript縮放功能的內容。所以我的所有觀點都應該對用戶可見。 （在英國將會有大約10個點）我想把它們全部展示出來，或者如果大部分都在倫敦地區，放大到那裏。

有沒有辦法以編程方式解決這個問題？

Answer 1

當然。您想要在註釋中找到最大和最小的緯度和經度值（您可以通過迭代map.annotations來完成），然後設置地圖以顯示所有這些值。

// pad our map by 10% around the farthest annotations 
#define MAP_PADDING 1.1 

// we'll make sure that our minimum vertical span is about a kilometer 
// there are ~111km to a degree of latitude. regionThatFits will take care of 
// longitude, which is more complicated, anyway. 
#define MINIMUM_VISIBLE_LATITUDE 0.01 

MKCoordinateRegion region; 
region.center.latitude = (minLatitude + maxLatitude)/2; 
region.center.longitude = (minLongitude + maxLongitude)/2; 

region.span.latitudeDelta = (maxLatitude - minLatitude) * MAP_PADDING; 

region.span.latitudeDelta = (region.span.latitudeDelta < MINIMUM_VISIBLE_LATITUDE) 
    ? MINIMUM_VISIBLE_LATITUDE 
    : region.span.latitudeDelta; 

region.span.longitudeDelta = (maxLongitude - minLongitude) * MAP_PADDING; 

MKCoordinateRegion scaledRegion = [map regionThatFits:region]; 
[map setRegion:scaledRegion animated:YES]; 

Answer 2

這是考慮到了，你是疊加到地圖上標註享有高度的改善（這樣註釋的頂部不會被切斷時，它的座標偏移量是在底部例）。或者進一步推廣，允許您以像素爲單位指定填充，而不是以百分比形式填充。它需要一個兩階段的過程來查找註釋的界限，然後進一步增加界限以考慮您的貼圖填充。

- (void) zoomToAnnotationsBounds:(NSArray *)annotations { 

CLLocationDegrees minLatitude = DBL_MAX; 
CLLocationDegrees maxLatitude = -DBL_MAX; 
CLLocationDegrees minLongitude = DBL_MAX; 
CLLocationDegrees maxLongitude = -DBL_MAX; 

for (MyAnnotation *annotation in annotations) { 
      double annotationLat = annotation.coordinate.latitude; 
      double annotationLong = annotation.coordinate.longitude; 
    minLatitude = fmin(annotationLat, minLatitude); 
    maxLatitude = fmax(annotationLat, maxLatitude); 
    minLongitude = fmin(annotationLong, minLongitude); 
    maxLongitude = fmax(annotationLong, maxLongitude); 
} 

    // See function below 
[self setMapRegionForMinLat:minLatitude minLong:minLongitude maxLat:maxLatitude maxLong:maxLongitude]; 

// If your markers were 40 in height and 20 in width, this would zoom the map to fit them perfectly. Note that there is a bug in mkmapview's set region which means it will snap the map to the nearest whole zoom level, so you will rarely get a perfect fit. But this will ensure a minimum padding. 
UIEdgeInsets mapPadding = UIEdgeInsetsMake(40.0, 10.0, 0.0, 10.0); 
CLLocationCoordinate2D relativeFromCoord = [self.mapView convertPoint:CGPointMake(0, 0) toCoordinateFromView:self.mapView]; 

// Calculate the additional lat/long required at the current zoom level to add the padding 
CLLocationCoordinate2D topCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.top) toCoordinateFromView:self.mapView]; 
CLLocationCoordinate2D rightCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.right) toCoordinateFromView:self.mapView]; 
CLLocationCoordinate2D bottomCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.bottom) toCoordinateFromView:self.mapView]; 
CLLocationCoordinate2D leftCoord = [self.mapView convertPoint:CGPointMake(0, mapPadding.left) toCoordinateFromView:self.mapView]; 

double latitudeSpanToBeAddedToTop = relativeFromCoord.latitude - topCoord.latitude; 
double longitudeSpanToBeAddedToRight = relativeFromCoord.latitude - rightCoord.latitude; 
double latitudeSpanToBeAddedToBottom = relativeFromCoord.latitude - bottomCoord.latitude; 
double longitudeSpanToBeAddedToLeft = relativeFromCoord.latitude - leftCoord.latitude; 

maxLatitude = maxLatitude + latitudeSpanToBeAddedToTop; 
minLatitude = minLatitude - latitudeSpanToBeAddedToBottom; 

maxLongitude = maxLongitude + longitudeSpanToBeAddedToRight; 
minLongitude = minLongitude - longitudeSpanToBeAddedToLeft; 

[self setMapRegionForMinLat:minLatitude minLong:minLongitude maxLat:maxLatitude maxLong:maxLongitude]; 
} 

-(void) setMapRegionForMinLat:(double)minLatitude minLong:(double)minLongitude maxLat:(double)maxLatitude maxLong:(double)maxLongitude { 

    MKCoordinateRegion region; 
    region.center.latitude = (minLatitude + maxLatitude)/2; 
    region.center.longitude = (minLongitude + maxLongitude)/2; 
    region.span.latitudeDelta = (maxLatitude - minLatitude); 
    region.span.longitudeDelta = (maxLongitude - minLongitude); 

    // MKMapView BUG: this snaps to the nearest whole zoom level, which is wrong- it doesn't respect the exact region you asked for. See http://stackoverflow.com/questions/1383296/why-mkmapview-region-is-different-than-requested 
    [self.mapView setRegion:region animated:YES]; 
} 

Answer 3

如果只針對iOS的7個或更多，你現在可以使用：

- (void)showAnnotations:(NSArray *)annotations 
       animated:(BOOL)animated 

Answer 4

所有完美的工作代碼修改的答案。

//Zooming the ploted Area 
- (void)zoomToAnnotationsBounds:(NSArray *)latLongArray { 
     __block CLLocationDegrees minLatitude = DBL_MAX; 
     __block CLLocationDegrees maxLatitude = -DBL_MAX; 
     __block CLLocationDegrees minLongitude = DBL_MAX; 
     __block CLLocationDegrees maxLongitude = -DBL_MAX; 

     [latLongArray enumerateObjectsUsingBlock:^(NSString *latLongObj, NSUInteger latLongIdx, BOOL *stop) { 
      latLongObj = [latLongArray objectAtIndex:latLongIdx]; 
      NSArray *latLongPoint = [latLongObj componentsSeparatedByString:@","]; 

      double annotationLat = [[latLongPoint objectAtIndex:0] doubleValue]; 
      double annotationLong = [[latLongPoint objectAtIndex:1] doubleValue]; 
      minLatitude = fmin(annotationLat, minLatitude); 
      maxLatitude = fmax(annotationLat, maxLatitude); 
      minLongitude = fmin(annotationLong, minLongitude); 
      maxLongitude = fmax(annotationLong, maxLongitude); 
     }]; 

     [self setMapRegionForMinLat:minLatitude minLong:minLongitude maxLat:maxLatitude maxLong:maxLongitude]; 
} 


-(void) setMapRegionForMinLat:(double)minLatitude minLong:(double)minLongitude maxLat:(double)maxLatitude maxLong:(double)maxLongitude { 

    // pad our map by 10% around the farthest annotations 

    // we'll make sure that our minimum vertical span is about a kilometer 
    // there are ~111km to a degree of latitude. regionThatFits will take care of 
    // longitude, which is more complicated, anyway. 

    MKCoordinateRegion region; 
    region.center.latitude = (minLatitude + maxLatitude)/2; 
    region.center.longitude = (minLongitude + maxLongitude)/2; 

    region.span.latitudeDelta = (maxLatitude - minLatitude) * MAP_PADDING; 

    region.span.latitudeDelta = (region.span.latitudeDelta < MINIMUM_VISIBLE_LATITUDE) 
    ? MINIMUM_VISIBLE_LATITUDE 
    : region.span.latitudeDelta; 

    region.span.longitudeDelta = (maxLongitude - minLongitude) * MAP_PADDING; 

    MKCoordinateRegion scaledRegion = [regionsMapView regionThatFits:region]; 
    [regionsMapView setRegion:scaledRegion animated:YES]; 

} 

Answer 5

這是一個古老的問題，我知道你可能不需要任何幫助。但是我只是把它放在那裏，因爲任何正在尋找方法的人現在都可以使用MKMapView以上的新方法。它既乾淨又容易。

宣言

SWIFT

func showAnnotations(_ annotations: [AnyObject]!, 
      animated animated: Bool) 

Objective-C的

- (void)showAnnotations:(NSArray *)annotations 
       animated:(BOOL)animated 

參數

註解要在 地圖上是可見的註釋。如果您希望地圖區域更改爲 動畫，則爲動畫;如果您想讓地圖立即顯示新區域 ，則爲NO，否則爲無動畫。

討論

調用此方法更新 該區域屬性的值和可能的其它屬性來 反映新的地圖區域。