从注释中获取数组索引

Question

您好，我想在用户点击注释时获取索引号。我有以下代码..

class ShopLocation: NSObject, MKAnnotation{

 var identifier = "Shop location"
 var title: String?
 var subtitle: String?
 var coordinate: CLLocationCoordinate2D

    init(name:String,lat:CLLocationDegrees,long:CLLocationDegrees,addInfo:String){
        title = name
        coordinate = CLLocationCoordinate2DMake(lat, long)
        subtitle = addInfo
    }

}
    class LocationList: NSObject {


        var shop = [ShopLocation]()

          override init(){
            shop += [ShopLocation(name:"t1", lat:35.673647,long:139.727686,addInfo:"info")]

            shop += [ShopLocation(name:"t2", lat:35.671928,long:139.760815,addInfo:"info")]

            shop += [ShopLocation(name:"t3", lat:35.713232,long:139.793467,addInfo:"info")]
    }

注释显示在地图上。我想获取索引，例如，如果 t1 被点击，我得到的索引为 1。

不知道写什么

func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {
    LocationList().shop.index(of: )

}

谢谢！

Answer 1

试试下面的代码：

func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {
    guard let annotation = view.annotation else {
        return
    }
    for (index, item) in LocationList().shop.enumerated() {
        if let title = view.annotation?.title {
            if item.name! == title! {
                print(index)
                break
            }
        }
    }

Answer 2

我假设 ShopLocation 已经符合 MKAnnotation，如果不符合则将其传递给 MKAnnotationView 的初始化器。这将使它在 delegate 方法中可用，通过 view.annotation

现在您可以访问 ShopLocation 实例，我想到了两种解决方案来找到它在 shop

中的索引

符合 Equatable - 这将启用 Array 的 firstIndex(of:) 方法（实际上 Collection 符合 Array )

 extension ShopLocation: Equatable {
     static func ==(lhs: ShopLocation, rhs: ShopLocation) -> Bool {
         // place here the conditions for two instances to be equal
     }

 // ... later in the code

 func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {
     guard let shopLocation = view.annotation as? ShopLocation else {
         // this early returns if the annotation is not a shop location,
         // if you don't wan't that you can use an if-let instead
         return
     }
     let index = LocationList().shop.firstIndex(of: shopLocation)
     // do what you need with the index
 }

使用 Array 的 firstIndex(where:) 方法（同样，实际上是 Collection :)

 func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {
     guard let shopLocation = view.annotation as? ShopLocation else {
         // this early returns if the annotation is not a shop location,
         // if you don't wan't that you can use an if-let instead
         return
     }
     let index = LocationList().shop.firstIndex(where: { shopLocation in
         return // same conditions as for the Equatable
     })
     // do what you need with the index
 }

就我个人而言，我推荐方法 #1，甚至 Apple 也推荐让值类型符合 Equatable。符合 Equatable 有助于减少代码，并启用除此处提到的 index(of:) 之外的许多其他功能。

Answer 3

   func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {
        var index = shops.index(of: view.annotation! as! ShopLocation)!
    }

帮我完成了工作。

从注释中获取数组索引

Get the array index from annotation

ios

swift

mapkit

mapkitannotation