swift - 将数据从 plist 传递到 DetailView

Question

我正在从 Objective C 转向 Swift 并重写我的应用程序。目前遇到基本问题，因此将不胜感激。

我已经设置了一个 map ，其中包含从 plist 数据中获取的注释，效果很好。我还可以将标题和副标题传递给第二个 View Controller - 没问题。

但是，我还想传递所选项目数据的所有其他字段，这就是我遇到的问题。

以前做得很好，但尽管进行了大量搜索，但找不到任何关于如何在 Swift 中做到这一点的指示。一个例子就完美了:-)

import MapKit

class Museums: NSObject, MKAnnotation {
    var title: String?
    var subtitle: String?
    var state: String?
    var latitude: Double
    var longitude:Double
    var coordinate: CLLocationCoordinate2D {
        return CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    }

    init(latitude: Double, longitude: Double) {
        self.latitude = latitude
        self.longitude = longitude
    }
}






class ViewController: UIViewController, MKMapViewDelegate {
    @IBOutlet weak var mapView: MKMapView!

    var infoToPass: String?

    //View did load
    override func viewDidLoad() {
        super.viewDidLoad()
       mapView.delegate = self

        zoomToRegion()

        let annotations = getMapAnnotations()

        // Add mappoints to Map
        mapView.addAnnotations(annotations)

        mapView.delegate = self

        }



    //Zoom to region

    func zoomToRegion() {

        let location = CLLocationCoordinate2D(latitude: 39.8, longitude: -98.6)

        let region = MKCoordinateRegionMakeWithDistance(location, 3150000.0, 3150000.0)

        mapView.setRegion(region, animated: true)
    }

    // Annotations

    func getMapAnnotations() -> [Museums] {
        var annotations:Array = [Museums]()

        //load plist file           
        var myMuseums: NSArray?
        if let path =    NSBundle.mainBundle().pathForResource("MyAnnotationsUSA", ofType: "plist") {
            myMuseums = NSArray(contentsOfFile: path)
        }
        if let items = myMuseums {
            for item in items {
                let lat = item.valueForKey("latitude") as! Double
                let long = item.valueForKey("longitude")as! Double
                let annotation = Museums(latitude: lat, longitude: long)
                annotation.title = item.valueForKey("title") as? String
                annotation.state = item.valueForKey("state") as? String
                annotations.append(annotation)
            }
        }

        return annotations
    }


    func mapView(mapView: MKMapView, viewForAnnotation annotations: MKAnnotation) -> MKAnnotationView? {
        let reuseIdentifier = "pin"
        var pin = mapView.dequeueReusableAnnotationViewWithIdentifier(reuseIdentifier) as? MKPinAnnotationView
        if pin == nil {
            pin = MKPinAnnotationView(annotation: annotations, reuseIdentifier: reuseIdentifier)
            //             pin!.pinColor = .Red
            pin!.canShowCallout = true
            pin!.rightCalloutAccessoryView = UIButton(type: .DetailDisclosure)
        } else
        {
            pin!.annotation = annotations
        }
        return pin
}



func mapView(mapView: MKMapView, annotationView: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
    if control == annotationView.rightCalloutAccessoryView {

        self.performSegueWithIdentifier("showDetail", sender: self)
    }
}


//prepare for segue

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        if self.mapView.selectedAnnotations.count == 0 {
            //no annotation selected
            return;
        }


        let  titleToPass = self.mapView.selectedAnnotations[0] //as? MKAnnotation

        print("\(infoToPass.title!)")

        let destination = segue.destinationViewController as! DetailViewController

        //This works
        destination.myLabelText = infoToPass.title!
        // This does not
        destination.myStateText = infoToPass.state

    }
}

Answer 1

在 DetailViewController 中，您应该声明保存附加数据的属性。然后，在 prepareForSegue 方法中设置这些属性，就像设置 myLabelText 一样。除了两种语言之间的明显差异之外，这实际上应该与 Objective-C 没有什么不同。

或者，如果这看起来不那么明显，请在您的问题中添加更多信息。

更新:查看您的评论并在 Xcode 中重新创建示例后，似乎由于您从 map View 中以 MKAnnotation 形式返回所选注释，因此显然不会有 state 成员。尝试将其转换到博物馆，如下所示:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if self.mapView.selectedAnnotations.count == 0 {
        //no annotation selected
        return
    }

    let infoToPass = self.mapView.selectedAnnotations[0] as! Museums  // <-- NOTE
    let destination = segue.destinationViewController as! DetailViewController
    destination.myLabelText = infoToPass.title!
    destination.myStateText = infoToPass.state
}