如何在覆盖视图下方缩放 MapView 注释？

Question

我需要缩放覆盖视图下方的地图注释。

我正在使用this method 放大到 2 个注释。

我似乎无法找到适合叠加视图下方的 2 个注释的方法，因为：

• 设置地图 edgePadding 会隐藏底部图钉
• 设置地图中心会隐藏底部图钉
• 我猜设置 latitudeDelta 会起作用，但如果引脚水平平行，则没有必要 + 它会因不同情况而变得混乱。

所以我想知道是否有一个我可能错过的问题的优雅解决方案？

这个叠加层还隐藏了注释标注，我想如果我有第一个问题的解决方案，这可以解决。

Answer 1

也许您应该尝试使用此代码来处理与注释的完美匹配：

- (void)zoomMapViewToFitAnnotations:(MKMapView *)mapView animated:(BOOL)animated
{ 
    NSArray *annotations = mapView.annotations;
    int count = [mapView.annotations count];
    if ( count == 0) { return; } //return if no annotations

    //convert NSArray of id <MKAnnotation> into an MKCoordinateRegion that can be used to set the map size
    //can't use NSArray with MKMapPoint because MKMapPoint is not an id
    MKMapPoint points[count]; //C array of MKMapPoint struct
    for( int i=0; i<count; i++ ) //load points C array by converting coordinates to points
    {
        CLLocationCoordinate2D coordinate = [(id <MKAnnotation>)[annotations objectAtIndex:i] coordinate];
        points[i] = MKMapPointForCoordinate(coordinate);
    }
    //create MKMapRect from array of MKMapPoint
    MKMapRect mapRect = [[MKPolygon polygonWithPoints:points count:count] boundingMapRect];
    //convert MKCoordinateRegion from MKMapRect
    MKCoordinateRegion region = MKCoordinateRegionForMapRect(mapRect);

    //add padding so pins aren't scrunched on the edges
    region.span.latitudeDelta  *= ANNOTATION_REGION_PAD_FACTOR;
    region.span.longitudeDelta *= ANNOTATION_REGION_PAD_FACTOR;
    //but padding can't be bigger than the world
    if( region.span.latitudeDelta > MAX_DEGREES_ARC ) { region.span.latitudeDelta  = MAX_DEGREES_ARC; }
    if( region.span.longitudeDelta > MAX_DEGREES_ARC ){ region.span.longitudeDelta = MAX_DEGREES_ARC; }

    //and don't zoom in stupid-close on small samples
    if( region.span.latitudeDelta  < MINIMUM_ZOOM_ARC ) { region.span.latitudeDelta  = MINIMUM_ZOOM_ARC; }
    if( region.span.longitudeDelta < MINIMUM_ZOOM_ARC ) { region.span.longitudeDelta = MINIMUM_ZOOM_ARC; }
    //and if there is a sample of 1 we want the max zoom-in instead of max zoom-out
    if( count == 1 )
    { 
        region.span.latitudeDelta = MINIMUM_ZOOM_ARC;
        region.span.longitudeDelta = MINIMUM_ZOOM_ARC;
    }
    [mapView setRegion:region animated:animated];
}

因此，您必须定义填充、最大度数弧和最小缩放弧。对于前。应该是这样的：

#define MINIMUM_ZOOM_ARC 0.05 //approximately 1 miles (1 degree of arc ~= 69 miles)
#define ANNOTATION_REGION_PAD_FACTOR 1.25
#define MAX_DEGREES_ARC 360

希望你会喜欢，干杯

Answer 2

如果您想在叠加层上使用触摸点，请为叠加层设置禁用用户交互。

为了设置缩放级别，我在绘制点后做了一些调整。您可以计算经纬度的平均值，然后根据叠加层的大小调整经度经度。这是我所做的：

            float latAvg,longAvg;


            latAvg = (location1.latitude + location.latitude)/2;
            longAvg = (location1.longitude + location.longitude)/2;
            MKCoordinateSpan span;// = MKCoordinateSpanMake(0.006, 0.006);

            span.latitudeDelta = fabs(location1.latitude - location.latitude);
            span.longitudeDelta = fabs(location1.longitude - location.longitude);


//Then adjust the lat longs delta according to your need.

            span.latitudeDelta = span.latitudeDelta + 0.0010;
            span.longitudeDelta = span.longitudeDelta + 0.0010;

            CLLocationCoordinate2D locationLatlng;
            locationLatlng.latitude = latAvg;
            locationLatlng.longitude = longAvg;

            MKCoordinateRegion viewRegion = MKCoordinateRegionMake(locationLatlng, span);


            [map setRegion:viewRegion animated:YES];

            [map regionThatFits:viewRegion];