Question

我有一个用于存储注释的数组。只有在您选择注释时，注释才会添加到数组中。添加后，如何检查数组中是否已有注释？我不想要任何重复 - 如果我选择一个已经在阵列中的引脚，它不应该再次添加。

这是我的代码：

    var pins = [[String : Double]]()

    func mapView(mapView: MKMapView!, didSelectAnnotationView view: MKAnnotationView!) {


    if editAndDoneButtonText.title == "Edit" {

        println("Pin Selected")

        var latFromPin = view.annotation.coordinate.latitude
        var lonFromPin = view.annotation.coordinate.longitude

        var selectedCoordinatePoint = ["latitude": latFromPin, "longitude": lonFromPin]
        var pinCoordinatePoint = ["latitude": latFromPin, "longitude": lonFromPin]


        pins.append(selectedCoordinatePoint)

        mapView.deselectAnnotation(view.annotation, animated: true)


    }

    // Remove pins from map by tapping on it
    if editAndDoneButtonText.title == "Done" {
        var annotationToRemove = view.annotation
        mapView.removeAnnotation(annotationToRemove)

        println("remove pin - didSelectAnnotationView")
    }


}

我在这里阅读其他答案并尝试过但没有成功。这不起作用，因为它允许重复。如果我在地图上选择多个引脚，它们会多次添加到数组中：

        if pins.isEmpty == true {
            pins.append(selectedCoordinatePoint)
        } else if pins.isEmpty == false {
            for pin in pins {
                if pin == selectedCoordinatePoint {
                    println("ALREADY INSIDE ARRAY")
                } else if pin != selectedCoordinatePoint {
                    pins.append(selectedCoordinatePoint)
                    println("ADDED TO ARRAY")
                }
            }
        }

我也试过使用扩展程序：

extension Array {
func contains<T where T : Equatable>(obj: T) -> Bool {
    return self.filter({$0 as? T == obj}).count > 0
    }
}

任何人都可以帮忙吗？

Answer 1

使用纬度和经度值作为Dictionary的关键字：

var pins = [String: [String : Double]]()

func mapView(mapView: MKMapView!, didSelectAnnotationView view: MKAnnotationView!) {

if editAndDoneButtonText.title == "Edit" {

    println("Pin Selected")

    var latFromPin = view.annotation.coordinate.latitude
    var lonFromPin = view.annotation.coordinate.longitude

    var selectedCoordinatePoint = ["latitude": latFromPin, "longitude": lonFromPin]
    var pinCoordinatePoint = ["latitude": latFromPin, "longitude": lonFromPin]

    // old pins.append(selectedCoordinatePoint)
    pins["\(latFromPin)_\(lonFromPin)"] = selectedCoordinatePoint

    mapView.deselectAnnotation(view.annotation, animated: true)
}

每个密钥只能存在一次。

所以你可以像以后一样检索它：

for key in pins.keys {
  let selectedCoordinatePoint = pins[key]!
  // go wild with it
}

我会建议你创建一个具有纬度和经度属性的简单Struct，而不是像这样使用字典数组。一个例子：

struct MySimpleCoordinate: Hashable {

  var hashValue: Int {
    get {
        return "\(latitude.hashValue),\(longitude.hashValue)".hashValue
    }
  }

  let latitude: Double
  let longitude: Double

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

// must be declared in the global scope! and not just in the class scope
func ==(lhs: MySimpleCoordinate, rhs: MySimpleCoordinate) -> Bool
{
  return lhs.hashValue == rhs.hashValue
}

现在让我们用新代码更新该委托：

var pins = Set<MySimpleCoordinate>()

func mapView(mapView: MKMapView!, didSelectAnnotationView view: MKAnnotationView!) {

  if editAndDoneButtonText.title == "Edit" {

  println("Pin Selected")

  var latFromPin = view.annotation.coordinate.latitude
  var lonFromPin = view.annotation.coordinate.longitude

  let mySimpleCoordinate = MySimpleCoordinate(latitude: latFromPin, longitude: lonFromPin)
  var pinCoordinatePoint = ["latitude": latFromPin, "longitude": lonFromPin]

  // old pins.append(selectedCoordinatePoint)
  // pins["\(latFromPin)_\(lonFromPin)"] = selectedCoordinatePoint

  // there will be no duplicates in a Set
  pins.insert(mySimpleCoordinate) 

  mapView.deselectAnnotation(view.annotation, animated: true)
}

要检索所有值，您可以这样做：

for coord in pins {
  println(coord.latitude)
  println(coord.longitude)
}

Swift - 如何检查地图注释（引脚）是否在数组中？

1 个答案: