Swift MKMapItems 与用户位置的距离

Question

有人可以帮我理解我需要添加什么来获取用户位置和地标之间的距离吗？我只是不确定要更改 distanceLabel.text 中的内容以使每个地标的数字发生变化。谢谢!

import UIKit
import MapKit

class ListedMapTableViewController: UITableViewController, CLLocationManagerDelegate {

var mapItems: [MKMapItem]!
var userLocation = CLLocationManager()
let distanceFormatter = MKDistanceFormatter()


override func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return mapItems.count
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "resultCell", for: indexPath) as! ListedTableViewCell

    // Configure the cell...
    let row = indexPath.row
    let item = mapItems[row]
    cell.nameLabel.text = item.name
    cell.detailLabel.text = item.phoneNumber
    let distanceInMeters : Double = self.userLocation.location!.distance(from: mapItems[row].placemark.location!)
    let distanceInMiles : Double = ((distanceInMeters.description as String).doubleValue * 0.00062137)
    cell.distanceLabel.text = "\(distanceInMiles.string(2)) miles away"

    return cell
}

 }


extension String {
var doubleValue: Double {
    return (self as NSString).doubleValue
}
}

//formats a double's decimal places
extension Double {
func string(_ fractionDigits:Int) -> String {
    let formatter = NumberFormatter()
    formatter.minimumFractionDigits = fractionDigits
    formatter.maximumFractionDigits = fractionDigits
    return formatter.string(from: NSNumber(value: fractionDigits))!
}
}

Answer 1

CLLocation 有一个 distanceFromLocation 方法，所以给定两个 CLLocations:

CLLocationDistance distanceInMeters = [location1 distanceFromLocation:location2];

或者在 Swift 3 中:

//: Playground - 名词:人们可以玩耍的地方

import CoreLocation


let coordinate₀ = CLLocation(latitude: 5.0, longitude: 5.0)
let coordinate₁ = CLLocation(latitude: 5.0, longitude: 3.0)

let distanceInMeters = coordinate₀.distance(from: coordinate₁) // result is in meters

你到这里的距离以米为单位，所以 1 英里 = 1609 米

if(distanceInMeters <= 1609)
 {
 // under 1 mile
 }
 else
{
 // out of 1 mile
 }