CLLocationManager，核心数据和阵列

Question

我已经有了这个功能，并且非常接近它的工作原理！我想我有一个转换问题。我可以将坐标转换为具有3个属性lat（Double），long（Double）和time（Date）的实体。这有效，我可以将内容打印到屏幕上，而且看起来不错。但是当我尝试提取并在地图上使用坐标时，它不起作用。我认为这是因为他们没有被认为是真正的坐标。有任何想法吗？

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 
    { 
     //ARRAY for lat/long data 
     var latArr:[Double] = [] 
     var longArr:[Double] = [] 
     var timeArr:[Date] = [] 

     let location = locations[0] 
     let annotation = MKPointAnnotation() 
     let span:MKCoordinateSpan = MKCoordinateSpanMake(0.01, 0.01) 
     let myLocation = CLLocationCoordinate2D(latitude: location.coordinate.latitude, longitude: location.coordinate.longitude) 
     //annotation.coordinate = myLocation 
     //annotation.title = "\(location.timestamp)" 
     //self.mapView.addAnnotation(annotation) 
     let region:MKCoordinateRegion = MKCoordinateRegionMake(myLocation, span) 
     self.mapView.setRegion(region, animated: true) 
     self.mapView.showsUserLocation = false //SET THIS 
     latitude.text = "latitude: " + "\(location.coordinate.latitude)" 
     longitude.text = "longitude: " + "\(location.coordinate.longitude)" 
     altitude.text = "altitude: " + "\(location.altitude)" 
     speed.text = "speed: " + "\(location.speed)" 
     timestamp.text = "timestamp: " + "\(location.timestamp)" 

     //START -- Core Data 
     let appDelegate = UIApplication.shared.delegate as! AppDelegate 
     let context = appDelegate.persistentContainer.viewContext 

     let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Data") 
     request.returnsObjectsAsFaults = false 

     let data = NSEntityDescription.insertNewObject(forEntityName: "Data", into: context) 
     //let data = NSNumber(double: self.location?.coordinate.latitude) 

     let dlat = Double("\(location.coordinate.latitude)") 
     let dlong = Double("\(location.coordinate.longitude)") 

     data.setValue(dlat, forKey: "lat") 
     data.setValue(dlong, forKey: "long") 
     data.setValue(location.timestamp, forKey: "time") 
     //END -- Core Data 

     do 
     { 
      try context.save() 
      //print("Saved") 
     } 
     catch 
     { 

     } 

     do 
     { 
      var lat: Double = 0 
      var long: Double = 0 
      let t = NSDate() 
      let results = try context.fetch(request) 

      if results.count > 0 
      { 
       for result in results as! [NSManagedObject] 
       { 
        if let datalat = result.value(forKey: "lat") as? Double 
        { 
         //latArr.append(datalat) 
         let lat = datalat 
         print(lat) 
        } 
        if let datalong = result.value(forKey: "long") as? Double 
        { 
         //longArr.append(datalong) 
         let long = datalong 
         print(long) 
        } 
        if let time = result.value(forKey: "time") as? Date 
        { 
         //timeArr.append(time) 
         let t = time 
         print(t) 
        } 
        let mLocation = CLLocationCoordinate2DMake(lat, long) 
        annotation.coordinate = mLocation 
        annotation.title = "\(t)" 
        self.mapView.addAnnotation(annotation) 
       } 
      } 
     } 
     catch 
     { 

     } 

Answer 1

我比你的代码，我使用在类似的场景功能和合并的任何差异（和做了一些编辑为简洁起见，你可以采取或离开）。相关部分如下：

let request = NSFetchRequest<Data>(entityName: "Data") 
let annotations: [MKAnnotation] = [] 

annotation.title = “\(t)” 

for result in results 
{ 
    if data.lat != nil && data.lon != nil 
    { 
     annotation.coordinate = CLLocationCoordinate2D(latitude: data.lat.doubleValue, longitude: data.lon.doubleValue) 
     annotations.append(annotation) 
    } 
    self.mapView.addAnnotations(annotations) 
    self.mapView.showAnnotations(annotations, animated: false) 
} 

我的代码工作，但它是雨燕3.0这样一些差异可能是由于从早期版本的变化，如果你使用2.2.or 2.3。我知道我需要将它从NSNumber（从CoreData）推送到Double，但是我认为如果这是问题，你会得到一个编译错误 - 不知道为什么你不是。正如我的评论中所提到的，如果航点仅仅在可见地图区域外，则显示注释将有所帮助。

除此之外，你的代码对我来说看起来还不错 - 让我知道它是否仍然存在。