从注解中获取数组索引

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，如果点击 t1，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，如果不符合则使其符合并将其传递给MKAnnotationView 的初始化程序。这将使其在delegate 方法中可用，通过view.annotation

既然您可以访问ShopLocation 实例，我想到了两种解决方案来在shop 中找到它的索引

1. 符合Equatable - 这将启用Array 的firstIndex(of:) 方法（实际上是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
    }
   

2. 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 也推荐符合 Equatable 的值类型。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)!
    }

为我完成了这项工作。