来自外部文件的位置坐标

Question

我正在Xcode 中创建一个应用程序。应用程序从外部文件中读取coordinates 并在table view 中列出。当用户点击任何列表单元格时，它会打开一个mapkit，它根据单元格的纬度和经度指向coordinate。

到目前为止，我的应用程序已经可以读取外部文件，并显示带有纬度和经度的 table view。它还打开了带有地图的视图，但问题是我无法使用坐标在地图上显示位置。

import UIKit
import MapKit


class listLoactionTableViewController: UITableViewController {

//array to store the list
var storeLoc = [String:Any]()

var arrayClient = NSMutableArray ()
var readings: [String] = [""]
//add map view

override func viewDidLoad() {
    super.viewDidLoad()

    //get the path where the file is stored
    let path = Bundle.main.path(forResource: "gps", ofType: "csv")

    //add file manager to check is the file exist to avoid crash
    let filemgr = FileManager.default

    //grab all content from teh file and store into the string
    //make an array withfrom the string by seperating line

    //iterate the content of the array

    //add the objects fr4om the array for display

    //add all teh field

    //display the amout of line we have title
    if filemgr.fileExists(atPath: path!){
        do {
            let fullText = try String(contentsOfFile: path!, encoding: String.Encoding.utf8)

            readings = fullText.components(separatedBy:  "\n") as [String]

            for i in 0..<readings.count{
                let listData = readings[i].components(separatedBy: ";") as [String]

                storeLoc["Latitude"] = "\(listData[0])"
                storeLoc["Longitude"] = "\(listData[1])"
                storeLoc["DateandTime"] = "\(listData[2])"


                arrayClient.add(storeLoc)
                                }
        } catch let error as NSError {
            print("error: \(error)")
        }
    }

    self.title = "Number of Inputs \(arrayClient.count)"


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

// MARK: - Table view data source

override func numberOfSections(in tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete implementation, return the number of rows
    return arrayClient.count
}


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

    let coord = arrayClient[indexPath.row]
    cell.detailTextLabel?.text = "Latitude:\((coord as AnyObject).object(forKey: "Latitude")!)   Longitude:\((coord as AnyObject).object(forKey: "Longitude")!)"
    cell.textLabel?.text = "Date and Time: \((coord as AnyObject).object(forKey: "DateandTime")!)"
    return cell
}

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    performSegue(withIdentifier: "oneSegue", sender: arrayClient[indexPath.row])

}

它正确显示所有坐标的列表。当我单击我的应用程序时，会打开一个包含 mapkit 的 segue

import UIKit
import MapKit

class showMapViewController: UIViewController {

@IBOutlet weak var showMap: MKMapView!

var selectedName = [String:Any]()

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

我尝试打印“selectedName.count”并得到 3，这是正确的。我也尝试根据索引打印，也得到了正确的值。

但是，我无法使用纬度和经度值在地图上显示位置。

请帮忙。

Answer 1

在showMapViewControllers viewDidLoad() 中使用此示例：

guard let latString =  selectedName["Latitude"] as? String,
    let longString =  selectedName["Longitude"] as? String,
    let latitude = Double(latString),
    let longitude = Double(longString)
    else {
        fatalError("You better handle the error here")
}

let center = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)        
let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))

showMap.setRegion(region, animated: true)