将CLLocationCoordinate2D转换为可以存储的String [英] Converting CLLocationCoordinate2D to a String that can be stored

问题描述

我正在尝试在一个ViewController中保存用户的坐标，以便它可以用于创建可以在另一个ViewController中显示的注释。

I'm trying to save the coordinates of a user while in one ViewController so that it can be used to create an Annotation that can displayed in another ViewController.

在视图控制器中存储坐标我正在使用代码

In the view controller that stores the coordinates I'm using the code

NSUserDefaults.standardUserDefaults().setObject( Location, forKey: "Location")

在地图视图控制器，显示我正在尝试使用代码获取坐标的注释

In the map view controller that displays the annotation I'm trying to get the coordinates using the code

let Location = NSUserDefaults.standardUserDefaults().stringForKey("Location")
var Annotation = MKPointAnnotation()
Annotation.coordinate = Location    

它告诉我类型 String？的值类型为 CLLocationCoordinate2D 。

It is telling me that the value of type String? to a value of type CLLocationCoordinate2D.

那么如何将 CLLocationCoordinate2D 坐标转换为类型 String ？

So how do I convert the CLLocationCoordinate2D coordinates into a value of type String?

推荐答案

通过这种方式，您可以将地点存储到 NSUserDefaults ：

This way you can store Locations to NSUserDefaults:

//First Convert it to NSNumber.
let lat : NSNumber = NSNumber(double: Location.latitude)
let lng : NSNumber = NSNumber(double: Location.longitude)

//Store it into Dictionary
let locationDict = ["lat": lat, "lng": lng]

//Store that Dictionary into NSUserDefaults
NSUserDefaults.standardUserDefaults().setObject(locationDict, forKey: "Location")

之后您可以这样访问：

//Access that stored Values
let userLoc = NSUserDefaults.standardUserDefaults().objectForKey("Location") as! [String : NSNumber]

//Get user location from that Dictionary
let userLat = userLoc["lat"]
let userLng = userLoc["lng"]

var Annotation = MKPointAnnotation()

Annotation.coordinate.latitude = userLat as! CLLocationDegrees  //Convert NSNumber to CLLocationDegrees
Annotation.coordinate.longitude = userLng as! CLLocationDegrees //Convert NSNumber to CLLocationDegrees

更新：

HERE 是您的示例项目。

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