@Jensemanns 在 Swift 4 中的回答，顺便说一句，这是我发现的唯一一个对我有用的解决方案来检测 a 上的点击MKPolyline：
let map = MKMapView()
let mapTap = UITapGestureRecognizer(target: self, action: #selector(mapTapped(_:)))
map.addGestureRecognizer(mapTap)
func mapTapped(_ tap: UITapGestureRecognizer) {
if tap.state == .recognized {
// Get map coordinate from touch point
let touchPt: CGPoint = tap.location(in: map)
let coord: CLLocationCoordinate2D = map.convert(touchPt, toCoordinateFrom: map)
let maxMeters: Double = meters(fromPixel: 22, at: touchPt)
var nearestDistance: Float = MAXFLOAT
var nearestPoly: MKPolyline? = nil
// for every overlay ...
for overlay: MKOverlay in map.overlays {
// .. if MKPolyline ...
if (overlay is MKPolyline) {
// ... get the distance ...
let distance: Float = Float(distanceOf(pt: MKMapPointForCoordinate(coord), toPoly: overlay as! MKPolyline))
// ... and find the nearest one
if distance < nearestDistance {
nearestDistance = distance
nearestPoly = overlay as! MKPolyline
}
}
}
if Double(nearestDistance) <= maxMeters {
print("Touched poly: \(nearestPoly) distance: \(nearestDistance)")
}
}
}
func distanceOf(pt: MKMapPoint, toPoly poly: MKPolyline) -> Double {
var distance: Double = Double(MAXFLOAT)
for n in 0..<poly.pointCount - 1 {
let ptA = poly.points()[n]
let ptB = poly.points()[n + 1]
let xDelta: Double = ptB.x - ptA.x
let yDelta: Double = ptB.y - ptA.y
if xDelta == 0.0 && yDelta == 0.0 {
// Points must not be equal
continue
}
let u: Double = ((pt.x - ptA.x) * xDelta + (pt.y - ptA.y) * yDelta) / (xDelta * xDelta + yDelta * yDelta)
var ptClosest: MKMapPoint
if u < 0.0 {
ptClosest = ptA
}
else if u > 1.0 {
ptClosest = ptB
}
else {
ptClosest = MKMapPointMake(ptA.x + u * xDelta, ptA.y + u * yDelta)
}
distance = min(distance, MKMetersBetweenMapPoints(ptClosest, pt))
}
return distance
}
func meters(fromPixel px: Int, at pt: CGPoint) -> Double {
let ptB = CGPoint(x: pt.x + CGFloat(px), y: pt.y)
let coordA: CLLocationCoordinate2D = map.convert(pt, toCoordinateFrom: map)
let coordB: CLLocationCoordinate2D = map.convert(ptB, toCoordinateFrom: map)
return MKMetersBetweenMapPoints(MKMapPointForCoordinate(coordA), MKMapPointForCoordinate(coordB))
}
斯威夫特 5.x 版本
let map = MKMapView()
let mapTap = UITapGestureRecognizer(target: self, action: #selector(mapTapped))
map.addGestureRecognizer(mapTap)
@objc func mapTapped(_ tap: UITapGestureRecognizer) {
if tap.state == .recognized {
// Get map coordinate from touch point
let touchPt: CGPoint = tap.location(in: map)
let coord: CLLocationCoordinate2D = map.convert(touchPt, toCoordinateFrom: map)
let maxMeters: Double = meters(fromPixel: 22, at: touchPt)
var nearestDistance: Float = MAXFLOAT
var nearestPoly: MKPolyline? = nil
// for every overlay ...
for overlay: MKOverlay in map.overlays {
// .. if MKPolyline ...
if (overlay is MKPolyline) {
// ... get the distance ...
let distance: Float = Float(distanceOf(pt: MKMapPoint(coord), toPoly: overlay as! MKPolyline))
// ... and find the nearest one
if distance < nearestDistance {
nearestDistance = distance
nearestPoly = overlay as? MKPolyline
}
}
}
if Double(nearestDistance) <= maxMeters {
print("Touched poly: \(String(describing: nearestPoly)) distance: \(nearestDistance)")
}
}
}
private func distanceOf(pt: MKMapPoint, toPoly poly: MKPolyline) -> Double {
var distance: Double = Double(MAXFLOAT)
for n in 0..<poly.pointCount - 1 {
let ptA = poly.points()[n]
let ptB = poly.points()[n + 1]
let xDelta: Double = ptB.x - ptA.x
let yDelta: Double = ptB.y - ptA.y
if xDelta == 0.0 && yDelta == 0.0 {
// Points must not be equal
continue
}
let u: Double = ((pt.x - ptA.x) * xDelta + (pt.y - ptA.y) * yDelta) / (xDelta * xDelta + yDelta * yDelta)
var ptClosest: MKMapPoint
if u < 0.0 {
ptClosest = ptA
}
else if u > 1.0 {
ptClosest = ptB
}
else {
ptClosest = MKMapPoint(x: ptA.x + u * xDelta, y: ptA.y + u * yDelta)
}
distance = min(distance, ptClosest.distance(to: pt))
}
return distance
}
private func meters(fromPixel px: Int, at pt: CGPoint) -> Double {
let ptB = CGPoint(x: pt.x + CGFloat(px), y: pt.y)
let coordA: CLLocationCoordinate2D = map.convert(pt, toCoordinateFrom: map)
let coordB: CLLocationCoordinate2D = map.convert(ptB, toCoordinateFrom: map)
return MKMapPoint(coordA).distance(to: MKMapPoint(coordB))
}