在Swift中从地图上计算距离和预计到达时间

Question

我目前使用的代码如下，它可以打开地图并提供驾车导航到特定的目的地。

let lat1 : NSString = "57.619302"
let lng1 : NSString = "11.954928"

let latitute:CLLocationDegrees =  lat1.doubleValue
let longitute:CLLocationDegrees =  lng1.doubleValue

let regionDistance:CLLocationDistance = 10000
let coordinates = CLLocationCoordinate2DMake(latitute, longitute)
let regionSpan = MKCoordinateRegionMakeWithDistance(coordinates, regionDistance, regionDistance)
let options = [
    MKLaunchOptionsMapCenterKey: NSValue(MKCoordinate: regionSpan.center),
    MKLaunchOptionsMapSpanKey: NSValue(MKCoordinateSpan: regionSpan.span),
    MKLaunchOptionsDirectionsModeKey: MKLaunchOptionsDirectionsModeDriving
]

let placemark = MKPlacemark(coordinate: coordinates, addressDictionary: nil)
let mapItem = MKMapItem(placemark: placemark)
mapItem.name = "Timo's Crib"

dispatch_async(dispatch_get_main_queue()) {
    mapItem.openInMapsWithLaunchOptions(options)
}

}))

现在地图打开后，您可以看到到目的地的预计到达时间和总距离等信息。我该如何提取或计算这些精确的信息？我只看过objective c的示例代码，但从未见过swift的。

- Timo Cengiz

Answer 1

您可以使用MKDirectionsRequest来实现。首先需要我们的当前位置，因为从您的代码中我们可以看到您已经有了目的地。我使用CLLocationManagerDelegate方法locationManager(_:didUpdateLocations:)。

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let sourcePlacemark = MKPlacemark(coordinate: locations.last!.coordinate, addressDictionary: nil)
    let sourceMapItem = MKMapItem(placemark: sourcePlacemark)
    ..
}

非常好。现在我们有了源项目和目标项目。现在只需请求（为了简化事情，我将您的代码放在方法内部，但目标位置背后的逻辑可能应从此方法中提取）：

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    // Get current position
    let sourcePlacemark = MKPlacemark(coordinate: locations.last!.coordinate, addressDictionary: nil)
    let sourceMapItem = MKMapItem(placemark: sourcePlacemark)

    // Get destination position
    let lat1: NSString = "57.619302"
    let lng1: NSString = "11.954928"
    let destinationCoordinates = CLLocationCoordinate2DMake(lat1.doubleValue, lng1.doubleValue)
    let destinationPlacemark = MKPlacemark(coordinate: destinationCoordinates, addressDictionary: nil)
    let destinationMapItem = MKMapItem(placemark: destinationPlacemark)

    // Create request
    let request = MKDirectionsRequest()
    request.source = sourceMapItem
    request.destination = destinationMapItem
    request.transportType = MKDirectionsTransportType.Automobile
    request.requestsAlternateRoutes = false
    let directions = MKDirections(request: request)
    directions.calculateDirectionsWithCompletionHandler { response, error in
        if let route = response?.routes.first {
            print("Distance: \(route.distance), ETA: \(route.expectedTravelTime)")
        } else {
            print("Error!")
        }
    }
}

- sunshinejr