ios - 从用户默认值加载数据时，我得到一个空的 CLLocationCoordinates 数组

Question

我正在尝试将来 self 的应用程序的跟踪部分的 CCLocationCoordinates 数组存储到 UserDefaults 中，并将跟踪路线的名称作为键，以便以后能够在函数中调用它。问题是，当我调用该函数时，出现索引超出范围错误。我检查了一下，数组是空的。由于我是用户默认值的新手，所以我尝试查看其他类似的帖子，但它们都是关于 NSUserDefaults 的，但没有找到解决方案。

存储和调用数组的函数代码如下:

func stopTracking2() {

        self.trackingIsActive = false
        self.trackigButton.backgroundColor = UIColor.yellow
        locationManager.stopUpdatingLocation()
        let stopRoutePosition = RouteAnnotation(title: "Route Stop", coordinate: (locationManager.location?.coordinate)!, imageName: "Route Stop")
        self.actualRouteInUseAnnotations.append(stopRoutePosition)



        print(actualRouteInUseCoordinatesArray)
        print(actualRouteInUseAnnotations)
        drawRoutePolyline()      // draw line to show route
//        checkAlerts2()           // check if there is any notified problem on our route and marks it with a blue circle, now called at programmed checking

        saveRouteToUserDefaults()
        postRouteToAnalitics() // store route anonymously to FIrebase

    }

    func saveRouteToUserDefaults() {

        // save actualRouteInUseCoordinatesArray : change for function
//        userDefaults.set(actualRouteInUseCoordinatesArray, forKey: "\(String(describing: userRoute))")

        storeCoordinates(actualRouteInUseCoordinatesArray)

    }

    // Store an array of CLLocationCoordinate2D
    func storeCoordinates(_ coordinates: [CLLocationCoordinate2D]) {
        let locations = coordinates.map { coordinate -> CLLocation in
            return CLLocation(latitude: coordinate.latitude, longitude: coordinate.longitude)
        }
        let archived = NSKeyedArchiver.archivedData(withRootObject: locations)
        userDefaults.set(archived, forKey: "\(String(describing: userRoute))")

        userDefaults.synchronize()
    }

    func loadRouteFromUserDefaults() {
        // gets entry from userRouteArray stored in userDefaults and append them into actualRouteInUseCoordinatesArray
        actualRouteInUseCoordinatesArray.removeAll()
        actualRouteInUseCoordinatesArray = userDefaults.object(forKey: "\(String(describing: userRoute))") as? [CLLocationCoordinate2D] ?? [CLLocationCoordinate2D]() // here we get the right set of coordinates for the route we are about to do the check on

        // load route coordinates from UserDefaults


//        actualRouteInUseCoordinatesArray = loadCoordinates()! //error found nil

    }


    // Return an array of CLLocationCoordinate2D
    func loadCoordinates() -> [CLLocationCoordinate2D]? {
        guard let archived = userDefaults.object(forKey: "\(String(describing: userRoute))") as? Data,
            let locations = NSKeyedUnarchiver.unarchiveObject(with: archived) as? [CLLocation] else {
                return nil
        }

        let coordinates = locations.map { location -> CLLocationCoordinate2D in
            return location.coordinate
        }

        return coordinates
    }

}



extension NewMapViewController {

    // ALERTS :

    func checkAlerts2() {

        loadRouteFromUserDefaults()        //load route coordinates to check in
        // CHECK IF ANY OBSTACLE IS OUN OUR ROUTE BY COMPARING DISTANCES

        while trackingCoordinatesArrayPosition != ( (actualRouteInUseCoordinatesArray.count) - 1) {
            print("checking is started")
            print(actualRouteInUseCoordinatesArray)
            let trackingLatitude = actualRouteInUseCoordinatesArray[trackingCoordinatesArrayPosition].latitude
            let trackingLongitude = actualRouteInUseCoordinatesArray[trackingCoordinatesArrayPosition].longitude
            let alertLatitude = alertNotificationCoordinatesArray[alertNotificationCoordinatesArrayPosition].latitude
            let alertLongitude = alertNotificationCoordinatesArray[alertNotificationCoordinatesArrayPosition].longitude

            let coordinateFrom = CLLocation(latitude: trackingLatitude, longitude: trackingLongitude)
            let coordinateTo = CLLocation(latitude: alertLatitude, longitude: alertLongitude)
            let coordinatesDistanceInMeters = coordinateFrom.distance(from: coordinateTo)

            // CHECK SENSITIVITY: sets the distance in meters for an alert to be considered an obstacle
            if coordinatesDistanceInMeters <= 10 {

                print( "found problem")
                routeObstacle.append(alertNotificationCoordinatesArray[alertNotificationCoordinatesArrayPosition]) // populate obstacles array
                trackingCoordinatesArrayPosition = ( trackingCoordinatesArrayPosition + 1)

            }
            else if alertNotificationCoordinatesArrayPosition < ((alertNotificationCoordinatesArray.count) - 1) {

                alertNotificationCoordinatesArrayPosition = alertNotificationCoordinatesArrayPosition + 1
            }
            else if  alertNotificationCoordinatesArrayPosition == (alertNotificationCoordinatesArray.count - 1) {

                trackingCoordinatesArrayPosition = ( trackingCoordinatesArrayPosition + 1)
                alertNotificationCoordinatesArrayPosition = 0
            }

        }

        findObstacles()

        NewMapViewController.checkCounter = 0


        displayObstacles()


    }

在扩展中你可以看到使用数组的函数。

在打印数组后，我立即收到索引超出范围错误。一如既往地感谢社区。

Answer 1

在尝试了提供的各种解决方案后，我决定重写整个内容。因此，在找到一篇关于如何将我的数组编码/解码为字符串的帖子后，我决定这是要走的路。它不应该对系统造成沉重负担，因为它是一个被保存的字符串。请让我知道您对此解决方案的看法。感谢@Sh_Khan 指出这是一个解码问题，感谢@Moritz 指出我的做法很糟糕。

所以代码是:

func storeRoute() {
    // first we code the CLLocationCoordinate2D array to string



    // second we store string into userDefaults

    userDefaults.set(encodeCoordinates(coords: actualRouteInUseCoordinatesArray), forKey: "\(String(describing: NewMapViewController.userRoute))")
}

func loadRoute() {

    //first se load string from user defaults
    let route = userDefaults.string(forKey: "\(String(describing: NewMapViewController.userRoute))")
    print("loaded route is \(route!))")

    //second we decode it into CLLocationCoordinate2D array
    actualRouteInUseCoordinatesArray = decodeCoordinates(encodedString: route!)
    print("decoded route array is \(actualRouteInUseCoordinatesArray))")

}

func encodeCoordinates(coords: [CLLocationCoordinate2D]) -> String {
    let flattenedCoords: [String] = coords.map { coord -> String in "\(coord.latitude):\(coord.longitude)" }
    let encodedString: String = flattenedCoords.joined(separator: ",")
    return encodedString
}
func decodeCoordinates(encodedString: String) -> [CLLocationCoordinate2D] {
    let flattenedCoords: [String] = encodedString.components(separatedBy: ",")
    let coords: [CLLocationCoordinate2D] = flattenedCoords.map { coord -> CLLocationCoordinate2D in
        let split = coord.components(separatedBy: ":")
        if split.count == 2 {
            let latitude: Double = Double(split[0]) ?? 0
            let longitude: Double = Double(split[1]) ?? 0
            return CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
        } else {
            return CLLocationCoordinate2D()
        }
    }
    return coords
}