MKMapView上适应所有的坐标

自己封装一下，不是程序内置的实现方式

- (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];

}