iphone - 获取 MKMapView 的边界

Question

为了设置对外部服务器的查询，我想获取我正在构建的 iPhone 应用程序中当前 map View 的边界。 UIView 应该响应边界，但似乎 MKMapView 没有。设置区域并放大 map 后，我尝试获取边界。我被困在第一步，即尝试获取代表 map 东南角和西北角的 CGPoints。之后我要使用:

- (CLLocationCoordinate2D)convertPoint:(CGPoint)point toCoordinateFromView:(UIView *)view

将点转换为 map 坐标。但我什至无法做到这一点......

//Recenter and zoom map in on search location
MKCoordinateRegion region =  {{0.0f, 0.0f}, {0.0f, 0.0f}};
region.center = mySearchLocation.searchLocation.coordinate;
region.span.longitudeDelta = 0.01f;
region.span.latitudeDelta = 0.01f;
[self.mapView setRegion:region animated:YES];


//After the new search location has been added to the map, and the map zoomed, we need to update the search bounds
//First we need to calculate the corners of the map
CGPoint se = CGPointMake(self.mapView.bounds.origin.x, mapView.bounds.origin.y);
CGPoint nw = CGPointMake((self.mapView.bounds.origin.x + mapView.bounds.size.width), (mapView.bounds.origin.y + mapView.bounds.size.height));
NSLog(@"points are: se %@, nw %@", se, nw);

代码编译时不会出现警告，但 se 和 nw 均为 null。查看 self.mapView.bounds.origin.x ，变量为 0。尝试直接 NSLog self.mapView.bounds.size.width 给我一个“程序收到信号:“EXC_BAD_ACCESS”。这似乎来自 NSLog。

有人知道从 MKMapView 的可见区域获取东南角和西北角(在 map 坐标中)的正确方法吗？

编辑:似乎每当您在这里问一些问题时，答案都会立即出现。我使用 %@ 而不是 @f 来打印 NSLog 中的每个变量，这会引发错误。我还发现了MKMapview的annotationVisibleRect属性。看来，annotationVisibleRect 是基于父 View 坐标的。

Answer 1

好吧，我正式回答了我自己的问题，但由于我在任何地方都找不到它，所以我将在这里发布答案:

//To calculate the search bounds...
//First we need to calculate the corners of the map so we get the points
CGPoint nePoint = CGPointMake(self.mapView.bounds.origin.x + mapView.bounds.size.width, mapView.bounds.origin.y);
CGPoint swPoint = CGPointMake((self.mapView.bounds.origin.x), (mapView.bounds.origin.y + mapView.bounds.size.height));

//Then transform those point into lat,lng values
CLLocationCoordinate2D neCoord;
neCoord = [mapView convertPoint:nePoint toCoordinateFromView:mapView];

CLLocationCoordinate2D swCoord;
swCoord = [mapView convertPoint:swPoint toCoordinateFromView:mapView];

SWIFT 5

public extension MKMapView {

  var newBounds: MapBounds {
    let originPoint = CGPoint(x: bounds.origin.x + bounds.size.width, y: bounds.origin.y)
    let rightBottomPoint = CGPoint(x: bounds.origin.x, y: bounds.origin.y + bounds.size.height)

    let originCoordinates = convert(originPoint, toCoordinateFrom: self)
    let rightBottomCoordinates = convert(rightBottomPoint, toCoordinateFrom: self)

    return MapBounds(
      firstBound: CLLocation(latitude: originCoordinates.latitude, longitude: originCoordinates.longitude),
      secondBound: CLLocation(latitude: rightBottomCoordinates.latitude, longitude: rightBottomCoordinates.longitude)
    )
  }
}

public struct MapBounds {
  let firstBound: CLLocation
  let secondBound: CLLocation
}

用法

self.mapView.newBounds