如何使用swift设置多注释数组

Question

下面的数组应该如何设置。我试图在我的地图上添加多个注释。我能够在 stackoverflow 上找到下面的代码，但他们没有显示如何设置数组。

var objects = [ 
                //how should the array be setup here 
              ]

for objecters in objects!{
    if let latit = objecters["Coordinates"]["Latitude"]{
        self.latitudepoint = latit as! String
        self.map.reloadInputViews()
    }
    else {
        continue
    }
    if let longi = objecters["Coordinates"]["Longitude"]{
        self.longitudepoint = longi as! String
        self.map.reloadInputViews()
    }
    else {
        continue
    }
    var annotation = MKPointAnnotation()
    var coord = CLLocationCoordinate2D(latitude: Double(self.latitudepoint)!,longitude: Double(self.longitudepoint)!)
    mapView.addAnnotation(annotation)
}

Answer 1

你可以这样做，例如：

let locations = [
    ["title": "New York, NY",    "latitude": 40.713054, "longitude": -74.007228],
    ["title": "Los Angeles, CA", "latitude": 34.052238, "longitude": -118.243344],
    ["title": "Chicago, IL",     "latitude": 41.883229, "longitude": -87.632398]
]

for location in locations {
    let annotation = MKPointAnnotation()
    annotation.title = location["title"] as? String
    annotation.coordinate = CLLocationCoordinate2D(latitude: location["latitude"] as! Double, longitude: location["longitude"] as! Double)
    mapView.addAnnotation(annotation)
}

或者，使用自定义类型，例如：

struct Location {
    let title: String
    let latitude: Double
    let longitude: Double
}

let locations = [
    Location(title: "New York, NY",    latitude: 40.713054, longitude: -74.007228),
    Location(title: "Los Angeles, CA", latitude: 34.052238, longitude: -118.243344),
    Location(title: "Chicago, IL",     latitude: 41.883229, longitude: -87.632398)
]

for location in locations {
    let annotation = MKPointAnnotation()
    annotation.title = location.title
    annotation.coordinate = CLLocationCoordinate2D(latitude: location.latitude, longitude: location.longitude)
    mapView.addAnnotation(annotation)
}

或者您可以将

for

循环替换为

map

：

let annotations = locations.map { location -> MKAnnotation in
    let annotation = MKPointAnnotation()
    annotation.title = location.title
    annotation.coordinate = CLLocationCoordinate2D(latitude: location.latitude, longitude: location.longitude)
    return annotation
}
mapView.addAnnotations(annotations)

最后，值得注意的是，你可以让你的自定义对象符合

MKAnnotation

协议，然后你就可以直接使用它，完全绕过

MKPointAnnotation

类型：

class Location: NSObject, MKAnnotation {
    dynamic var title: String?
    dynamic var subtitle: String?
    dynamic var coordinate: CLLocationCoordinate2D

    convenience init(title: String? = nil, subtitle: String? = nil, latitude: Double, longitude: Double) {
        self.init(title: title, subtitle: subtitle, coordinate: CLLocationCoordinate2D(latitude: latitude, longitude: longitude))
    }

    init(title: String? = nil, subtitle: String? = nil, coordinate: CLLocationCoordinate2D) {
        self.title = title
        self.subtitle = subtitle
        self.coordinate = coordinate

        super.init()
    }
}

let locations = [
    Location(title: "New York, NY",    latitude: 40.713054, longitude: -74.007228),
    Location(title: "Los Angeles, CA", latitude: 34.052238, longitude: -118.243344),
    Location(title: "Chicago, IL",     latitude: 41.883229, longitude: -87.632398)
]

mapView.addAnnotations(locations)

注意，

dynamic

限定符的使用是可选的，但如果您打算使注释视图可拖动，则非常有用。