将地图图钉保存到数组，Swift [英] Saving map pins to array, Swift

问题描述

我正在创建一个地图类型的应用程序，一旦用户按下按钮，便会将销钉放置在其当前位置的地图上。我正在尝试将地图图钉保存到数组中，以便在应用关闭后仍然保留。

I am creating a map type application, once the user presses a button a pin is dropped to the map at their current location. I am trying to save map pins to an array so that they remain once the app is closed.

到目前为止，这是我的代码：

Here is my code so far:

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let location = locations.last
    let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
    let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.004, longitudeDelta: 0.004))
    self.placesMap?.setRegion(region, animated: true)
    self.locationManager.stopUpdatingLocation()
}

func locationManager(manager: CLLocationManager, didFailWithError error: NSError)
{
    print("Error code: " + error.localizedDescription)
}

// Add button action
@IBAction func addButton(sender: AnyObject) {
    let annotation = MKPointAnnotation()
    annotation.coordinate = CLLocationCoordinate2D(latitude: self.placesMap.userLocation.coordinate.latitude, longitude: self.placesMap.userLocation.coordinate.longitude)
    self.placesMap.addAnnotation(annotation)
    self.locationManager.startUpdatingLocation()
}

我如何将引脚信息保存到每次应用程序都会重新加载的数组中

How can I save the pin information to an array which is reloaded each time the app is opened?

推荐答案

如果要在应用程序启动之间保留数据，而又不存储太多数据，那么简单的方法是使用NSUserDefaults。您可以这样说：

If you want to persist data between application launches, and you are not storing much data, the easy way is to use NSUserDefaults. You can do this by saying something like:

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let location = locations.last
    let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
    let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.004, longitudeDelta: 0.004))
    self.placesMap?.setRegion(region, animated: true)
    self.locationManager.stopUpdatingLocation()



     let locationDictionary:[String:Double] = ["latitude":center.latitude,"longitude":center.longitude]
     var locationArray = [[String:Double]]()
     if NSUserDefaults.standardUserDefaults().objectForKey("locationArray") != nil {
        locationArray = NSUserDefaults.standardUserDefaults().objectForKey("locationArray") as! [[String:Double]]

    }

    locationArray.append(locationDictionary)

    NSUserDefaults.standardUserDefaults().setObject(locationArray, forKey: "locationArray")
    NSUserDefaults.standardUserDefaults().synchronize()
    }

应用重新启动后，您将需要读出这些位置。您可以在viewDidLoad中做到这一点。例如：

You will then need to read out those locations when the app relaunches. You can do that in viewDidLoad. For example:

override func viewDidLoad(){
    super.viewDidLoad()
    if NSUserDefaults.standardUserDefaults().objectForKey("locationArray") != nil {
    for dictionary in NSUserDefaults.standardUserDefaults().objectForKey("locationArray") as! [[String:Double]]{
        let center = CLLocationCoordinate2D(latitude: dictionary["latitude"]!, longitude: dictionary["longitude"]!)
        let annotation = MKPointAnnotation()
        annotation.coordinate = center
        self.placesMap.addAnnotation(annotation)
    }
  }
}

如果要删除所有存储的位置，您可以说：

If you want to remove all of the stored locations you can say something like:

    func removeStoredLocations(){
     NSUserDefaults.standardUserDefaults().removeObjectForKey("locationArray")
     NSUserDefaults.standardUserDefaults().synchronize()
    }

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