Ios viewDidLoad（）swift4.1中的ReverseGeocodeLocation完成用法

Swift版本：4.1

你好，我在swift方面比初学者多一点。在“按用户位置的订单应用程序”中工作。在用户下订单之前，我通过

反向地理位置函数

控制用户的“国家”和“城市”名称。并将这些值写入firebase实时数据库childs中

我的数据结构就像

 -TR
   -Ankara
       -userID
           -Order(consist of user lat, user long, user mail, userOrder)

用户可以订购和取消他/她的订单。但我还想检查用户是否关闭手机并返回应用程序，应用程序应该检查数据库，如果当前用户发出命令，则必须更改按钮标签、ButtonCancelstate=true以及我们吉祥物的图像

这就是我如何获得订单的user

coord

，以及数据结构名称的“countrycode”和“city”

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

    let location = locations [0]

    if let coord = manager.location?.coordinate {
        userLocation = coord

    }


    let geoCoder = CLGeocoder()
    geoCoder.reverseGeocodeLocation(location) {(placemark, error) in
        if error != nil {
            print("there is an error")
        } else {

        var placeMark: CLPlacemark?
        placeMark = placemark?[0]


        // City
        if let city = placeMark?.locality {
            self.userCity = city as String

        }

        // Country
        if let country = placeMark?.isoCountryCode {
            self.userCountry = country as String
            }
        }
    }
}

我用“订单按钮”中的“国家”和“城市”作为例子

            orderHasBeenCalled = true
            buttonLabelText.text = "CANCEL/EDIT"
            imgView.image = UIImage(named: "...")
            let orderRequestDictionary: [String:Any] = ["..."]
            databaseREF.child(userCountry).child(userCity).child(userID!).setValue(orderRequestDictionary)

它工作完美用户可以发送订单，删除它，即使用户注销它也删除了（整个代码不包括在内）

现在的问题是，我想检查当

viewdiload（）

加载我正在使用的这个时，用户是否有订单

if let userID = FirebaseAuth.Auth.auth().currentUser?.uid {
        databaseRef.child(userCountry).child(userCity).queryOrdered(byChild: userID!).observe(.childAdded, with: { (snapshot) in
            self.OrderHasBeenCalled = true
            self.buttonLabelText.text = "CANCEL/EDIT"
            self.imgView.image = UIImage(named: "...")
            databaseRef.child(self.userCountry).child(self.userCity).removeAllObservers()
        })
   }

现在的问题是，我在internet上读到的

reversegeocode

是异步的或类似的，而且当viewDidLoad（）加载“检查是否有顺序的代码”时，它似乎还没有准备好，因为它找不到在childs中搜索姓名的值，所以导致应用程序崩溃

Terminating app due to uncaught exception 'InvalidPathValidation', reason: '(child:) Must be a non-empty string and not contain '.' '#' '$' '[' or ']''

为了在orderbutton中使用userCountry和userCity，我在viewDidLoad（）之前定义了它们

我尝试了很多方法，但没有真正弄清楚如何在viewdidload（）中实现反向代码完成。顺便说一句，我也尝试了

viewdideappease（）

，但它也给出了userCountry（）和userCity（）零

---

我希望我的问题清楚易懂。如果答案是这样的，我们将不胜感激。在互联网上做了很多研究，有些我尝试过，有些我不理解，甚至不知道如何尝试。我最不希望看到的地方是堆栈溢出。现在感谢所有友好地回答我问题的人。

我想改变一下方法。使用异步函数后，必须避免使用同步请求值

有几种方法可以从异步函数中进行嵌套调用，从我使用这种方法得到的代码中，可以根据您的需要进行调整，并且应该可以正常工作

/////////attention the scope (must be above class declaration)
typealias CompletionGetAddress = (_ userCity : String?, _ userCountry: String?, _ success: Bool) -> Void
var userLocation = CLLocationCoordinate2D()
var locationManager = CLLocationManager()
//

class viewController: ... {
func viewDidLoad() {

    yourLocationManager.requestLocation()

    // you should implement some code to ensure your userLocation from your locationManager is not nil and a valid location

    if let userID = FirebaseAuth.Auth.auth().currentUser?.uid {
        if self.userCity != "" {
            databaseRef.child(userCountry).child(userCity).queryOrdered(byChild: userID!).observe(.childAdded, with: { (snapshot) in
                self.OrderHasBeenCalled = true
                self.buttonLabelText.text = "CANCEL/EDIT"
                self.imgView.image = UIImage(named: "...")
                databaseRef.child(self.userCountry).child(self.userCity).removeAllObservers()
            })
        } else {
            getAddress { (city, country, success) in
                if success {
                    self.userCity = city
                    self.userCountry = country
                    databaseRef.child(userCountry).child(userCity).queryOrdered(byChild: userID!).observe(.childAdded, with: { (snapshot) in
                        self.OrderHasBeenCalled = true
                        self.buttonLabelText.text = "CANCEL/EDIT"
                        self.imgView.image = UIImage(named: "...")
                        databaseRef.child(self.userCountry).child(self.userCity).removeAllObservers()
                    })
                }
            }           
        }
    }
} 
}


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

    let location = locations [0]

    if let coord = manager.location?.coordinate {
        userLocation = coord /// attention here 

    }
}


func getAddress(completion: @escaping CompletionGetAddress) {
    let geoCoder = CLGeocoder()
    geoCoder.reverseGeocodeLocation(userLocation) {(placemark, error) in
        if error != nil {
            print("there is an error")
            completion(nil, nil, false)
        } else {
            var city: String = ""
            var country: String = ""
            var placeMark: CLPlacemark?
            placeMark = placemark?[0]
            // City
            if let c = placeMark?.locality {
                city = c
            }
            // Country
            if let c = placeMark?.isoCountryCode {
                country = c
            }
            completion(city, country, true)
        }
    }
}   

---

我会尽快回复。为了确保，请将

typealias

声明放在要对我的问题进行全局编辑的类的顶部。如果你能在空闲时间登记，那就太棒了。甚至，如果你不能检查，你给我的代码我在任何地方都找不到。我真的很感激。以前是

userLocation

现在是

drinkerLocation

（比user更好的饮酒者，但我认为输入有误）更改

class viewController:。。。{var userLocation=CLLocationCoordinate2D（）var locationManager=CLLocationManager（）

by

var userLocation=CLLocationCoordinate2D（）var locationManager=CLLocationManager（）类视图控制器：。。。{

请参见上面的类声明，并更改您的

didUpdateLocation

drinker…否。是因为您正在viewController中重新声明它…我将更新代码

/////////attention the scope (must be above class declaration)
typealias CompletionGetAddress = (_ userCity : String?, _ userCountry: String?, _ success: Bool) -> Void
var userLocation = CLLocationCoordinate2D()
var locationManager = CLLocationManager()
//

class viewController: ... {
func viewDidLoad() {

    yourLocationManager.requestLocation()

    // you should implement some code to ensure your userLocation from your locationManager is not nil and a valid location

    if let userID = FirebaseAuth.Auth.auth().currentUser?.uid {
        if self.userCity != "" {
            databaseRef.child(userCountry).child(userCity).queryOrdered(byChild: userID!).observe(.childAdded, with: { (snapshot) in
                self.OrderHasBeenCalled = true
                self.buttonLabelText.text = "CANCEL/EDIT"
                self.imgView.image = UIImage(named: "...")
                databaseRef.child(self.userCountry).child(self.userCity).removeAllObservers()
            })
        } else {
            getAddress { (city, country, success) in
                if success {
                    self.userCity = city
                    self.userCountry = country
                    databaseRef.child(userCountry).child(userCity).queryOrdered(byChild: userID!).observe(.childAdded, with: { (snapshot) in
                        self.OrderHasBeenCalled = true
                        self.buttonLabelText.text = "CANCEL/EDIT"
                        self.imgView.image = UIImage(named: "...")
                        databaseRef.child(self.userCountry).child(self.userCity).removeAllObservers()
                    })
                }
            }           
        }
    }
} 
}


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

    let location = locations [0]

    if let coord = manager.location?.coordinate {
        userLocation = coord /// attention here 

    }
}


func getAddress(completion: @escaping CompletionGetAddress) {
    let geoCoder = CLGeocoder()
    geoCoder.reverseGeocodeLocation(userLocation) {(placemark, error) in
        if error != nil {
            print("there is an error")
            completion(nil, nil, false)
        } else {
            var city: String = ""
            var country: String = ""
            var placeMark: CLPlacemark?
            placeMark = placemark?[0]
            // City
            if let c = placeMark?.locality {
                city = c
            }
            // Country
            if let c = placeMark?.isoCountryCode {
                country = c
            }
            completion(city, country, true)
        }
    }
}