Custom MKAnnotation dictionary input（CLLocationCoordinate2d）

Question

import MapKit 
import UIKit 

class Point: NSObject, MKAnnotation { 
    var id: String? 
    var title: String? 
    var coordinate: CLLocationCoordinate2D 
    var subtitle: String? 



    init(id: String, dictionary: Dictionary<String, AnyObject>){ 


     self.id = id 

     if let title = dictionary["title"] as? String { 
      self.title = title 
     } 

     if let subtitle = dictionary["subtitle"] as? String { 
      self.subtitle = subtitle 
     } 

     if let coords = dictionary["coordinates"] as? [String:[String:Double]] { 
      var latitude = coords.values.first!["latitude"]! 
      var longitude = coords.values.first!["longitude"]! 
      var location = CLLocationCoordinate2D(latitude: latitude, longitude: longitude) 
      self.coordinate = location 
     } 

    } 

錯誤：屬性self.coordinate未在隱式生成的super.init調用時初始化。

任何想法如何解決這個問題？

感謝您的一些建議。

Answer 1

要麼你應該在

if let coords = dictionary["coordinates"] as? [String:[String:Double]] { 
... 
} else { 
self.coordinate = <assign a default location> 
} 

或者

其他情況下，指定一個默認值不應該，如果沒有座標創建對象。所以讓你的init是可選的。

init?(id: String, dictionary: Dictionary<String, AnyObject>){ 

     if let coords = dictionary["coordinates"] as? [String:[String:Double]] { 
      self.id = id 

      if let title = dictionary["title"] as? String { 
       self.title = title 
      } 

      if let subtitle = dictionary["subtitle"] as? String { 
       self.subtitle = subtitle 
      } 
      var latitude = coords.values.first!["latitude"]! 
      var longitude = coords.values.first!["longitude"]! 
      var location = CLLocationCoordinate2D(latitude: latitude, longitude: longitude) 
      self.coordinate = location 
     } else { 
      return nil 
     } 
}