使用 CLGeocoder() 将地址转换为坐标的函数未正确返回坐标答案

【问题标题】：Function using CLGeocoder() to get convert address to coordinates is not returning coordinates properly使用 CLGeocoder() 将地址转换为坐标的函数未正确返回坐标
【发布时间】：2020-06-24 05:07:43
【问题描述】：

以下是我用来为每辆卡车创建位置的结构。

卡车

struct Truck {
    var name: String
    var imageOfTruck: String
    var cuisineType: String
    var customerRatings: [Int]
    var customerRatingAve: Int
    var menu: [MenuItem]
    var currentLocation: Location
}

位置

struct Location {

    var location: String
    var coordinates: CLLocationCoordinate2D {
        
        let geoCoder = CLGeocoder()
        var tempCoordinates = CLLocationCoordinate2D(latitude: 0, longitude: 0)
        
        geoCoder.geocodeAddressString(location) { (placemarks, error) in
        guard
            let placemarks = placemarks,
            let location = placemarks.first?.location
            
        else {
            print("location not found!")
            return
        }
            
        // Use your location
        let latitude = location.coordinate.latitude
        let longitude = location.coordinate.longitude
            print("latitude: \(latitude)")
            print("longitude: \(longitude)")
            tempCoordinates.latitude = latitude
            tempCoordinates.longitude = longitude

        }
        return tempCoordinates
    }
    
    var departureTime: String
    var nextLocation: NextLocation
}

let truckOne = Truck(name: "truck one",
                     imageOfTruck: "image of truck one",
                     cuisineType: "mexican",
                     customerRatings: [4,4,4],
                     customerRatingAve: 4,
                     menu: [MenuItem(itemName: "taco",
                     itemDescription: "spicy tacos",
                     itemPhotos: ["image one", "image two"],
                     customerRatings: [4,4,4],
                     customerRatingAvg: 4)],
                     currentLocation: Location(location: "physical address goes here (removed for stack overflow)",
                                               departureTime: "5PM",
                                               nextLocation: NextLocation(location: "321 address street",
                                                                          arrivalTime: Date(),
                                                                          departureTime: Date())))

let truckTwo = Truck(name: "truck two",
                     imageOfTruck: "image of truck two",
                     cuisineType: "pizza",
                     customerRatings: [4,4,4],
                     customerRatingAve: 4,
                     menu: [MenuItem(itemName: "pepperoni pizza",
                                     itemDescription: "delicious pepperoni",
                                     itemPhotos: ["image one", "image two"],
                                     customerRatings: [4,4,4],
                                     customerRatingAvg: 4)],
                     currentLocation: Location(location: "physical address goes here (removed for stack overflow)",
                                               departureTime: "4PM",
                                               nextLocation: NextLocation(location: "333 cool st",
                                                                          arrivalTime: Date(),
                                                                          departureTime: Date())))

let arrayOfTrucks = [truckOne, truckTwo]

下面是我需要将纬度和经度拉入的函数。

    func convertAddressToCoordinates() {
                
        for trucks in arrayOfTrucks {
            print("truck name: \(trucks.name) truck coordinates: \(trucks.currentLocation.coordinates)")
        }
    }

函数打印

卡车名称：卡车一卡车坐标：CLLocationCoordinate2D(latitude: 0.0, longitude: 0.0)

卡车名称：卡车两卡车坐标：CLLocationCoordinate2D(latitude: 0.0, longitude: 0.0)

但是，在计算机属性coordinates 中，经纬度设置正确。从coordinates 变量中的打印语句中，打印出以下内容

纬度：30.2968677

经度：-81.6114142

纬度：30.1535125

经度：-81.6429059

计算属性是否在实际获得latitude 和longitude 之前返回tempCoordinates？如果是这样，有什么解决方法？

【问题讨论】：

geocodeAddressString 异步运行，这意味着稍后会调用闭包。所以它不适用于计算属性。您可能希望使用自己的完成处理程序闭包编写一个函数。

标签： swift xcode

【解决方案1】：

您可以使用完成处理程序编写这样的结构

struct Location {
    
    var location: String
    func getLocation(completion: @escaping (CLLocationCoordinate2D?)-> Void) {
        let geoCoder = CLGeocoder()
        
        
        geoCoder.geocodeAddressString(location) { (placemarks, error) in
            
            guard
                let placemarks = placemarks,
                let location = placemarks.first?.location?.coordinate
                
                else {
                    print("location not found!")
                    completion(nil)
                    return
            }
            
            completion(location)
            
        }
        
    }
}

【讨论】：