iOS设置了MKMapView中心，因此提供的位置在底部中心 [英] iOS set MKMapView center so supplied location is in the bottom center

问题描述

我有一个MKMapView和一个从未更改过的CLLocationCoordinate2D.我想做的是将地图居中，以便将此坐标放置在地图的底部中心.我可以使用以下简单的方法将地图定位在此坐标上:

I have a MKMapView and a never changing CLLocationCoordinate2D. What I am trying to do is center the map so that this coordinate will be placed at the bottom center of the map. I am able to center the map on this coordinate with the simple:

MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(mapCenter, 10000, 10000);
[self.mapView setRegion:viewRegion animated:YES];

但是如何使地图居中于使该mapCenter坐标位于地图底部的点上呢?我希望它可以工作，无论地图的初始缩放级别如何.

But how can I make it so that the map centers on the point that would make this mapCenter coordinate be placed at the bottom of the map? I would like it to work regardless of the initial zoom level of the map if possible.

推荐答案

我写了一个快速的方法来解决这个问题...

I wrote you a quick method that should do the trick...

在获得位置坐标居中的MKCoordinateRegion之后，可以通过添加该区域的纬度跨度的一部分(在本例中为四分之一)来创建新的CLLocationCoordinate2D中心点.使用新的中心点和旧区域的跨度创建一个新的坐标区域，将其设置为MKMapView的region，您就可以开始了.

After getting a MKCoordinateRegion with the location coordinate centered, you can create a new CLLocationCoordinate2D center point by adding a fraction of that region's latitudinal span (in this case, a fourth). Create a new coordinate region using the new center point and the old region's span, set it as the region of the MKMapView, and you're good to go.

P.s. -如果您希望位置始终在底部居中，请通过添加该区域的纬度跨度的一半(而不是四分之一)来创建新的CLLocationCoordinate2D中心点.

P.s. - If you want the location centered all the way at the bottom, create the new CLLocationCoordinate2D center point by adding half of the region's latitudinal span (instead of a fourth).

-(void)setLocation:(CLLocationCoordinate2D)location inBottomCenterOfMapView:(MKMapView*)mapView
{
    //Get the region (with the location centered) and the center point of that region
    MKCoordinateRegion oldRegion = [mapView regionThatFits:MKCoordinateRegionMakeWithDistance(location, 800, 800)];
    CLLocationCoordinate2D centerPointOfOldRegion = oldRegion.center;

    //Create a new center point (I added a quarter of oldRegion's latitudinal span)
    CLLocationCoordinate2D centerPointOfNewRegion = CLLocationCoordinate2DMake(centerPointOfOldRegion.latitude + oldRegion.span.latitudeDelta/4.0, centerPointOfOldRegion.longitude);

    //Create a new region with the new center point (same span as oldRegion)
    MKCoordinateRegion newRegion = MKCoordinateRegionMake(centerPointOfNewRegion, oldRegion.span);

    //Set the mapView's region
    [worldView setRegion:newRegion animated:YES];
}

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