Question

有人可以帮我理解如何按照已经拉动的距离来组织我的tableview，并显示mapItems离用户位置有多远的数据。没见过有人对实际的tableview给出答案。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
}

}

//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))!
}
}

修改

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中的这个答案中调用原始函数（sortedMapItems）将太沉重且不必要，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，这样您就不必再在distance cellForRow..函数>

用户的Swift组织UITableView距离MKMapItems的距离

1 个答案: