在 segue 和解雇期间崩溃

Question

我有一个问题，我的应用程序在我的表视图控制器中

崩溃

import UIKit
import MapKit
import CoreLocation
class CourseClass: UITableViewController, CLLocationManagerDelegate, MKMapViewDelegate {
    @IBOutlet weak var map: MKMapView!
    struct User {
        var name: String
        var images: UIImage
        var coordinate: (Double, Double)
        var type: String
    }
    /* var place = ["Caffè Spagar", "Duks", "Posta station", "Barnum", "Elephant Club", "Cinema", "Space", "Andromeda", "Rodolf", "Devil Chair"] */
    var rows = 0
    var users = [User]()
    let CS = User(name: "Caffè Spagar", images: UIImage(named: "Caffè Spagar.png")! , coordinate:(12345,54678), type: "Pub")
    let D = User(name: "Duks", images: UIImage(named: "Duks.png")! , coordinate:(13345,54128), type: "Shopping")
    let PS = User(name: "Posta station", images: UIImage(named: "Posta station.png")! , coordinate:(18795,34556), type: "Resturant")
    let B = User(name: "Barnum", images: UIImage(named: "Barnum.png")! , coordinate:(46655,43554), type: "Pub")
    let EC = User(name: "Elephant Club", images: UIImage(named: "Elephant Club.png")! , coordinate:(12325,21435), type: "Disco")
    let C = User(name: "Cinema", images: UIImage(named: "Cinema.png")! , coordinate:(11235,12343), type: "Cinema")
    let S = User(name: "Space", images: UIImage(named: "Space.png")! , coordinate:(12345,66432), type: "Cinema")
    let A = User(name: "Andromeda", images: UIImage(named: "Andromeda.png")! , coordinate:(64545,23443), type: "Sport")
    let R = User(name: "Rodolf", images: UIImage(named: "Rodolf.png")! , coordinate:(64545,34358), type: "Shopping")
    let DC = User(name: "Devil Chair", images: UIImage(named: "Devil Chair.png")! , coordinate:(56656,54678), type: "Shopping")
    override func viewDidLoad() {
        super.viewDidLoad()
        map.showsUserLocation = true
        map.delegate = self
        users.append(CS)
        users.append(D)
        users.append(PS)
        users.append(B)
        users.append(EC)
        users.append(C)
        users.append(S)
        users.append(A)
        users.append(R)
        users.append(DC)
    }
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        insertRowsMode3()
    }
    func insertRowsMode2() {
        for i in 0..<users.count {
            insertRowMode2(ind: i, usr: users[i])
        }
    }
    func insertRowMode2(ind:Int,usr:User) {
        let indPath = IndexPath(row: ind, section: 0)
        rows = ind + 1
        tableView.insertRows(at: [indPath], with: .right)
    }
    func insertRowsMode3() {
        rows = 0
        insertRowMode3(ind: 0)
    }
    func insertRowMode3(ind:Int) {
        let indPath = IndexPath(row: ind, section: 0)
        rows = ind + 1
        tableView.insertRows(at: [indPath], with: .right)
        guard ind < users.count-1 else { return }
        DispatchQueue.main.asyncAfter(deadline: .now()+0.15) {
            self.insertRowMode3(ind: ind+1)
        }
    }    
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return rows
    }
    public override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
      let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! MyTableViewCell
      let user = users[indexPath.row]
        cell.myImage.image = user.images
        cell.myLabel.text = user.name
        cell.myTypeLabel.text = user.type
    /*  cell.myImage.image = UIImage(named: (place[indexPath.row] + ".png"))
        cell.myLabel.text = place[indexPath.row]
    */
        return (cell)
    }
    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
       performSegue(withIdentifier: "goToLast" , sender: users[indexPath.row])
    }
    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 100
    }
    @IBAction func mapTapped(_ sender: Any) {
    let userLocation = map.userLocation
    let region = MKCoordinateRegionMakeWithDistance((userLocation.location?.coordinate)!,2000,2000)       
    map.setRegion(region, animated: true)
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "goToLast" {
        guard let vc = segue.destination as? FinalClass else { return }
        let guest = segue.destination as! FinalClass
              guest.local = sender as! String
             guest.localImage = UIImage(named: (sender as! String) + ".png")!     
            guest.localType = sender as! String            
        }
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }    
}

正是在这个功能中

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "goToLast" {           
        guard let vc = segue.destination as? FinalClass else { return }
        let guest = segue.destination as! FinalClass
              guest.local = sender as! String
             guest.localImage = UIImage(named: (sender as! String) + ".png")!            
            guest.localType = sender as! String       
    }
}

问题是

无法将类型"Myapp.CourseClass.User"的值转换为"Swift.String"。

同样在遇到此问题之前，当我关闭下一个场景以返回此处时，该应用程序崩溃了。有人知道如何调整我的代码以使其工作吗？

Answer 1

guest.local = sender as! String
             guest.localImage = UIImage(named: (sender as! String) + ".png")!
            guest.localType = sender as! String

问题似乎在这里，尝试将"发件人"的类型作为其 Any 并且我认为它是用户类型，这是崩溃的原因

无法将类型"Myapp.CourseClass.User"的值转换为 "迅捷字符串">

这意味着您正在强制将用户类型对象强制转换为字符串。

可以固定为哈立德回答

 if let user = sender as? User {
          guest.local = user.local
         guest.localImage = user.image
        guest.localType = user.localType
     }

查找确切崩溃原因的另一种干净调试方法是：

• 进入 Xcode 左侧"导航器"选项卡中的"断点导航器"。

• 创建一个所有异常断点，如下图所示，该断点当您运行应用程序时，将在确切的崩溃行停止您的代码调试开启。

Answer 2

您正在发送一个用户类，然后将该用户类强制转换为字符串

试试这个

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "goToLast" {
    guard let vc = segue.destination as? FinalClass else { return }
    let guest = segue.destination as! FinalClass
         if let user = sender as? User {
          guest.local = user.local
         guest.localImage = user.image
        guest.localType = user.localType
     }

    }
}