如何存储MKPolyline属性作为可变换在IOS coredata与swift？ [英] How to store an MKPolyline attribute as transformable in IOS coredata with swift?

问题描述

允许在Swift中的CoreData中存储MKPolyline所需的代码是什么。

例如，如果我有一个我想要保存MKPolyline的核心数据实体（例如myEntity），并且添加了polyline作为可变换的，并在xcode中将其设置为可变换。还生成了NSManagedObject子类。

myEntity.swift

  import UIKit 
 import CoreData 
 import MapKit 
 class myEntity：NSManagedObject {
} 
  

myEntity + CoreDataProperties.swift

  import Foundation 
 import CoreData 
 extension myEntity {
 @NSManaged var title：String 
 @NSManaged var polyline：NSObject？问题 - 需要什么代码才能使其正常工作？
问题 - 需要什么代码才能正常工作？    
 
 
（我注意到这个post目标c，但是我很难理解/ port /让这个工作 -  ）
解决方案
存储折线对象并保存到核心数据：
  let context = self.fetchedResultsController.managedObjectContext 
 let entity = self.fetchedResultsController.fetchRequest.entity！ 
 let newManagedObject = NSEntityDescription.insertNewObjectForEntityForName（entity.name !, inManagedObjectContext：context）
 let polylineObj = polyline（）//用于测试目的。 
 let polylineData = polylineToArchive（polylineObj）
 newManagedObject.setValue（polylineData，forKey：polyline）
 context.save（）
  
从 NSManagedObject 中取消归档折线：
  let object = self.fetchedResultsController.objectAtIndexPath（indexPath）as！ NSManagedObject 
 let data = object.valueForKey（polyline）as！ NSData 
 let polyline = polylineUnarchive（data）
 log（polyline！）
  
 MKPolyline arhiver和unarchiver函数。还有一些帮助函数。
  func polylineUnarchive（polylineArchive：NSData） - > MKPolyline？ {
 guard let data = NSKeyedUnarchiver.unarchiveObjectWithData（polylineArchive），
 let polyline = data as？ [Dictionary< String，AnyObject>] else {
 return nil 
} 
 var locations：[CLLocation] = [] 
折线中的项{
如果允许= item [latitude]？doubleValue，
 let longitude = item [longitude]？doubleValue {
 let location = CLLocation（latitude：latitude，longitude：longitude）
 locations .append（location）
} 
} 
 var coordinates = locations.map（{（location：CLLocation） - > CLLocationCoordinate2D in return location.coordinate}）
 let result = MKPolyline（坐标：& coordinates，count：locations.count）
返回结果
} 
 
 func polylineToArchive（polyline：MKPolyline） - > NSData {
 let coordsPointer = UnsafeMutablePointer< CLLocationCoordinate2D> .alloc（polyline.pointCount）
 polyline.getCoordinates（coordsPointer，range：NSMakeRange（0，polyline.pointCount））
 var coords： ; String，AnyObject>] = [] 
 for i in 0 ..< polyline.pointCount {
 let latitude = NSNumber（double：coordsPointer [i] .latitude）
 let longitude = NSNumber（double：coordsPointer [i] .longitude）
 let coord = [latitude：latitude，longitude：longitude] 
 coords.append（coord）
} 
 let polylineData = NSKeyedArchiver.archivedDataWithRootObject（coords）
 return polylineData 
} 
 
 func polyline（） - > MKPolyline {
 let locations = [CLLocation（latitude：37.582691，longitude：127.011186），CLLocation（latitude：37.586112，longitude：127.011047），CLLocation（latitude：37.588212，longitude：127.010438）] 
 var coordinates = location.map（{（location：CLLocation） - > CLLocationCoordinate2D in return location.coordinate}）
 let polyline = MKPolyline（coordinates：& coordinates，count：locations.count）
 return polyline 
} 
 
 func log（polyline：MKPolyline）{
 let coordsPointer = UnsafeMutablePointer< CLLocationCoordinate2D> .alloc（polyline.pointCount）
 polyline.getCoordinates（coordsPointer，range：NSMakeRange （0，polyline.pointCount））
 var coords：[Dictionary< String，AnyObject>] = [] 
 for i in 0 ..< polyline.pointCount {
 let latitude = NSNumber （double：coordsPointer [i] .latitude）
 let longitude = NSNumber（double：coordsPointer [i] .longitude）
 let coord = [latitude：latitude，longitude：longitude $ b coords.append（coord）
} 
 print（coords）
} 
  
 
What would be the code required to allow the storage of an MKPolyline in CoreData in swift.  


So for example if I had one of my core data entities (say "myEntity") for which I wanted to save an MKPolyline, and have added the "polyline" field as transformable, and have set it to "transformable" in xcode.  Also have produced NSManagedObject subclass.

myEntity.swift
import UIKit
import CoreData
import MapKit
class myEntity: NSManagedObject {
}
myEntity+CoreDataProperties.swift
import Foundation
import CoreData
extension myEntity {
    @NSManaged var title: String
    @NSManaged var polyline: NSObject? 
}
Question - What code is required to allow this to work?

( I do note this post re objective-c, however I'm struggling to understand/port/get this to work - How do you store data from NSMutable Array in Core Data? )
解决方案
Archive polyline object and save to Core Data:
    let context = self.fetchedResultsController.managedObjectContext
    let entity = self.fetchedResultsController.fetchRequest.entity!
    let newManagedObject = NSEntityDescription.insertNewObjectForEntityForName(entity.name!, inManagedObjectContext: context)
    let polylineObj = polyline() // For test purpose.
    let polylineData = polylineToArchive(polylineObj)
            newManagedObject.setValue(polylineData, forKey: "polyline")
        context.save()
Unarchive polyline from the NSManagedObject:
    let object = self.fetchedResultsController.objectAtIndexPath(indexPath) as! NSManagedObject
    let data = object.valueForKey("polyline") as! NSData
    let polyline = polylineUnarchive(data)
    log(polyline!)
MKPolyline arhiver and unarchiver functions. As well some helper functions.
func polylineUnarchive(polylineArchive: NSData) -> MKPolyline? {
    guard let data = NSKeyedUnarchiver.unarchiveObjectWithData(polylineArchive),
        let polyline = data as? [Dictionary<String, AnyObject>] else {
        return nil
    }
    var locations: [CLLocation] = []
    for item in polyline {
        if let latitude = item["latitude"]?.doubleValue,
            let longitude = item["longitude"]?.doubleValue {
            let location = CLLocation(latitude: latitude, longitude: longitude)
            locations.append(location)
        }
    }
    var coordinates = locations.map({(location: CLLocation) -> CLLocationCoordinate2D in return location.coordinate})
    let result = MKPolyline(coordinates: &coordinates, count: locations.count)
    return result
}

func polylineToArchive(polyline: MKPolyline) -> NSData {
    let coordsPointer = UnsafeMutablePointer<CLLocationCoordinate2D>.alloc(polyline.pointCount)
    polyline.getCoordinates(coordsPointer, range: NSMakeRange(0, polyline.pointCount))
    var coords: [Dictionary<String, AnyObject>] = []
    for i in 0..<polyline.pointCount {
        let latitude = NSNumber(double: coordsPointer[i].latitude)
        let longitude = NSNumber(double: coordsPointer[i].longitude)
        let coord = ["latitude" : latitude, "longitude" : longitude]
        coords.append(coord)
    }
    let polylineData = NSKeyedArchiver.archivedDataWithRootObject(coords)
    return polylineData
}

func polyline() -> MKPolyline {
    let locations = [CLLocation(latitude: 37.582691, longitude: 127.011186), CLLocation(latitude: 37.586112,longitude: 127.011047), CLLocation(latitude: 37.588212, longitude: 127.010438)]
    var coordinates = locations.map({(location: CLLocation) -> CLLocationCoordinate2D in return location.coordinate})
    let polyline = MKPolyline(coordinates: &coordinates, count: locations.count)
    return polyline
}

func log(polyline: MKPolyline) {
    let coordsPointer = UnsafeMutablePointer<CLLocationCoordinate2D>.alloc(polyline.pointCount)
    polyline.getCoordinates(coordsPointer, range: NSMakeRange(0, polyline.pointCount))
    var coords: [Dictionary<String, AnyObject>] = []
    for i in 0..<polyline.pointCount {
        let latitude = NSNumber(double: coordsPointer[i].latitude)
        let longitude = NSNumber(double: coordsPointer[i].longitude)
        let coord = ["latitude" : latitude, "longitude" : longitude]
        coords.append(coord)
    }
    print(coords)
}


                        
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