xcode - 场景类的更改导致错误，Xcode/Swift

Question

我正在尝试制作一个小型 iPad 应用程序，其中包含“关于”页面。当我尝试更改以模式显示的关于页面场景的类时，我遇到了问题，因为当用户尝试访问此页面时应用程序崩溃。我希望将其类更改为“ViewController”，它与我的主窗口( map View )是同一类，以便通过“关于”页面上的按钮创建操作。

目前，我无法从“关于”页面按住 Ctrl 键并拖动到 .Swift 文件，除非更改其类。不知道为什么会发生这种情况:(

控制台打印的错误如下:

fatal error: unexpectedly found nil while unwrapping an Optional value
0 specialised_fatalErrorMessage(StaticString, StaticString, StaticString, Uint) -> () –

这是我的场景 Storyboard:

这是完整的 ViewController.Swift 代码:

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate, UISearchBarDelegate, UIPopoverPresentationControllerDelegate {

    var location: CLLocation!
    let locationManager = CLLocationManager()

    // Map variables
    var searchController:UISearchController!
    var annotation:MKAnnotation!
    var localSearchRequest:MKLocalSearchRequest!
    var localSearch:MKLocalSearch!
    var localSearchResponse:MKLocalSearchResponse!
    var error:NSError!
    var pointAnnotation:MKPointAnnotation!
    var pinAnnotationView:MKPinAnnotationView!

    @IBOutlet weak var mapView: MKMapView!
    @IBOutlet weak var segmentedControl: UISegmentedControl!
    @IBOutlet weak var showSearchBar: UIBarButtonItem!
    @IBOutlet weak var addButton: UIBarButtonItem!
    @IBOutlet weak var moreStuff: UIBarButtonItem!    

    @IBAction func addButton(sender: AnyObject) {
        let annotation = MKPointAnnotation()
        annotation.coordinate = CLLocationCoordinate2D(latitude: self.mapView.userLocation.coordinate.latitude, longitude: self.mapView.userLocation.coordinate.longitude)
        self.mapView.addAnnotation(annotation)
        self.locationManager.startUpdatingLocation()

    }

    @IBAction func showSearchBar(sender: UIBarButtonItem!) {
        searchController = UISearchController(searchResultsController: nil)
        searchController.hidesNavigationBarDuringPresentation = false
        self.searchController.searchBar.delegate = self
        presentViewController(searchController, animated: true, completion: nil)

    }

    @IBAction func moreStuff(sender: AnyObject) {
        self.performSegueWithIdentifier("showMoreStuff", sender:self)
    }


    @IBAction func refresh(sender: AnyObject) {

        self.locationManager.startUpdatingLocation()
    }

    @IBAction func segmentedControl(sender: UISegmentedControl!) {

        if sender.selectedSegmentIndex == 0{

            mapView.mapType = MKMapType.Standard
        }
        else if sender.selectedSegmentIndex == 1{

            mapView.mapType = MKMapType.Satellite
        }
        else if sender.selectedSegmentIndex == 2{

            mapView.mapType = MKMapType.Hybrid
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        self.locationManager.delegate = self

        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest

        self.locationManager.requestWhenInUseAuthorization()

        self.locationManager.startUpdatingLocation()

        self.mapView.showsUserLocation = true

    }

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

// location delegate methods

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    let location = locations.last

    let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)

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

    self.mapView.setRegion(region, animated: true)

    self.locationManager.stopUpdatingLocation()

}

func locationManager(manager: CLLocationManager, didFailWithError error: NSError)
{
    print("Error code: " + error.localizedDescription)
}

func searchBarSearchButtonClicked(searchBar: UISearchBar){

    searchBar.resignFirstResponder()
    dismissViewControllerAnimated(true, completion: nil)
    if self.mapView.annotations.count != 0{
        annotation = self.mapView.annotations[0]
        self.mapView.removeAnnotation(annotation)
    }

    localSearchRequest = MKLocalSearchRequest()
    localSearchRequest.naturalLanguageQuery = searchBar.text
    localSearch = MKLocalSearch(request: localSearchRequest)
    localSearch.startWithCompletionHandler { (localSearchResponse, error) -> Void in

        if localSearchResponse == nil{
            let alertController = UIAlertController(title: nil, message: "No Such Place", preferredStyle: UIAlertControllerStyle.Alert)
            alertController.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.Default, handler: nil))
            self.presentViewController(alertController, animated: true, completion: nil)
            return
        }

        self.pointAnnotation = MKPointAnnotation()
        self.pointAnnotation.title = searchBar.text
        self.pointAnnotation.coordinate = CLLocationCoordinate2D(latitude: localSearchResponse!.boundingRegion.center.latitude, longitude:     localSearchResponse!.boundingRegion.center.longitude)


        self.pinAnnotationView = MKPinAnnotationView(annotation: self.pointAnnotation, reuseIdentifier: nil)
        self.mapView.centerCoordinate = self.pointAnnotation.coordinate
    }
}

}

我是 Swift 新手，因此非常感谢任何帮助。谢谢!

编辑:这是应用程序崩溃后呈现给我的错误屏幕:

Answer 1

我没有使用过mapKit，但我仍在尝试。

查看您的错误，您遇到了零崩溃，这表明您的某个属性为零，但您尝试使用它。

快速浏览一下你的代码，发现你还没有初始化

var localSearchResponse....

再说一次，我不太了解 MK API，所以我不能 100 确定我所说的是否相关。

您是否检查过所有 IBOutlet 均已正确连接？

发生这种情况时，您在哪一行发生崩溃？您是否在切换到“关于”页面之前或之后遇到崩溃？