Swift 按用户与 MKMapItems 的距离组织 UITableView

Question

有人可以帮助我了解如何按距离组织我的 tableview，该距离已经拉动并显示有关 mapItems 与用户位置的距离的数据。还没有看到有人在实际的 tableview 上给出答案。谢谢你。

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
}

}

//get string value of double without casting
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: self))!
}
}

编辑

import UIKit
import MapKit

class ListedMapTableViewController: UITableViewController, CLLocationManagerDelegate {

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

func sortedMapItems() -> [MKMapItem]! {
    return self.mapItems.sorted(by: { (a, b) -> Bool in
        return self.userLocation.location!.distance(from: a.placemark.location!) > self.userLocation.location!.distance(from: b.placemark.location!)
    })
}

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

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return sortedMapItems().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 = sortedMapItems()[row]
    cell.nameLabel.text = item.name
    cell.detailLabel.text = item.phoneNumber
    let distanceInMeters : Double = self.userLocation.location!.distance(from: sortedMapItems()[row].placemark.location!)
    let distanceInMiles : Double = ((distanceInMeters.description as String).doubleValue * 0.00062137)
    cell.distanceLabel.text = "\(distanceInMiles.string(2)) miles away"

    return cell
}

}

//get string value of double without casting
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: self))!
}
}

第二次编辑

 import UIKit
 import MapKit

 class ListedMapTableViewController: UITableViewController, CLLocationManagerDelegate {

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

override func viewDidLoad() {
    super.viewDidLoad()

    func sortMapItems()  {
        self.mapItems = self.mapItems.sorted(by: { (a, b) -> Bool in
            return self.userLocation.location!.distance(from: a.placemark.location!) > self.userLocation.location!.distance(from: b.placemark.location!)
        })
    }
}

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
}

}

//get string value of double without casting
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: self))!
}
}

Answer 1

按距离排序：

func sortedMapItems() -> [MKMapItem] {
    return self.mapItems.sorted(by: { (a, b) -> Bool in
        return self.userLocation.location!.distance(from: a.placemark.location!) > 
               self.userLocation.location!.distance(from: b.placemark.location!)
    })
}

编辑：创建一个函数来对您的 mapitems 进行排序，然后在 viewDidLoad 中调用它：

override func viewDidLoad() {
    super.viewDidLoad()
    self.sortMapItems()

}
func sortMapItems()  {
        self.mapItems = self.mapItems.sorted(by: { (a, b) -> Bool in
            return self.userLocation.location!.distance(from: a.placemark.location!) > self.userLocation.location!.distance(from: b.placemark.location!)
        })
    }

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
}

在cellForRowRowAtIndexPath的这个答案中调用原始函数（sortedMapItems）将过于繁重且不必要，因为该函数将被重复调用。

更好的方法是重新创建您的数据结构并添加每个项目与用户位置的距离，这样您就不必在 cellForRow..[ 中再次调用 distance 函数=15=]

Swift 按用户与 MKMapItems 的距离组织 UITableView

Swift Organize UITableView by Users Distance from MKMapItems

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