如何将当前用户位置保存为默认值？答案

【问题标题】：How do I save the current user location in defaults?如何将当前用户位置保存为默认值？
【发布时间】：2019-07-05 19:48:00
【问题描述】：

我正在尝试为用户提供保存当前位置的选项。我使用默认值来保存它，我发现了如何获取用户位置。但我不确定如何结合这两个任务。所以这是我的问题：

如何让我的函数调用用户位置，以便保存？

@IBAction func addLocation(_ sender: Any) {

// CALL LOCATION MANAGER TO GET LOCATION IN LAT AND LONG    
    self.saveDefaults()

    }

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    guard let locValue: CLLocationCoordinate2D = manager.location?.coordinate else { return }
    print("locations = \(locValue.latitude) \(locValue.longitude)")
}

func saveDefaults()
{
    UserDefaults.standard.set(self.pickers, forKey: "pickers")
    print("SAVED PICKERS: \(pickers)")

}

这是我最近的尝试，但我不知道为什么我的结构 (lat: ,long:) 没有接受输入

@IBAction func addLocation(_ sender: Any) {

    var locations: [CLLocation]
    let manager: CLLocationManager

    let userLocation:CLLocation = locations[0] as CLLocation

    // Call stopUpdatingLocation() to stop listening for location updates,
    // other wise this function will be called every time when user location changes.

    manager.stopUpdatingLocation()

    print("user latitude = \(userLocation.coordinate.latitude)")
    print("user longitude = \(userLocation.coordinate.longitude)")

    self.pickers.append(pickerStruct(lat: userLocation.coordinate.latitude, long: userLocation.coordinate.longitude))

    self.saveDefaults()

    }

【问题讨论】：

标签： swift core-location userdefaults

【解决方案1】：

Sujal 的回答中使用的函数已被弃用。以下是功能的当前（2021 年）工作版本：

// Save location to UserDefaults
if let encodedLocation = try? NSKeyedArchiver.archivedData(withRootObject: location, requiringSecureCoding: false) {
    UserDefaults.standard.set(encodedLocation, forKey: "savedLocation")
}

// Load the last saved location
if let loadedLocation = UserDefaults.standard.data(forKey: "savedLocation"),
   let decodedLocation = try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(loadedLocation) as? CLLocation {
    // Use the decodedLocation as you want
}

【讨论】：

【解决方案2】：

@IBAction func addLocation(_ sender: Any) {
    locationManager.startUpdatingLocation() //This will call the delegate method below where you can save the location
}

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    guard locations.count > 0 else {
        return
    }

    guard let location = locations.last else {
        return
    }

    locationManager.stopUpdatingLocation() //Stop location updates after getting the location and save that location as below

    let encodedLocation = NSKeyedArchiver.archivedData(withRootObject: location)
    UserDefaults.standard.set(encodedLocation, forKey: "savedLocation")

}

从 UserDefaults 取回位置：

let previousLocationEncoded = UserDefaults.standard.object(forKey: "savedLocation") as? Data
let previousLocationDecoded = NSKeyedUnarchiver.unarchiveObject(with: previousLocationEncoded!) as! CLLocation

【讨论】：

我不确定你说得对不对。我想在用户想要的时候保存位置（当他开始按下按钮的动作时）。如果我理解正确，每次更改位置时都会保存它，对吗？
@Roman H 我已根据您的要求更新了答案:)