2

我对可观察对象还有另一个问题。

在“位置 1”行的视图中，我有用于编辑地址的文本视图（并将其保存到必须在视图中显示的状态属性“文本”中）。
状态变量“text”必须从类 LocationObserver 属性“currentAddress”初始化。我只是试图设置视图的初始化有人可以帮助我吗？

提前致谢！

最好的

德拉甘


The View 


struct PickFoto: View {
    @ObservedObject var observeLocation = LocationObserver.shared()!
    @State private var address = LocationObserver.shared()?.currentAddress ?? " "

...    

TextView(text: $text, isEditing: $isEditing) // Position 1


Text("current Address (observeLocation): \(observeLocation.currentAddress)") // Position 2
...
}

The Shared Object

class  LocationObserver: NSObject, CLLocationManagerDelegate, ObservableObject {
    // This published property value  has to be the initial value   
    // for the TextView (the property $text. how to to this??)

    @Published var currentAddress = " " 

    static var instance: LocationObserver?

    var locationManager = CLLocationManager()
    var defaultLocation = CLLocation(latitude: 52.516861, longitude:13.356796)

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        let currentLocation = locations.last?.coordinate



        convertGPSToAdress(coordinates: locations.last ?? defaultLocation,
                           completion: { (retStr: String) in
                                            self.currentAddress = retStr // set the  @Published property
                                            print("currentAddress in EscapingClosure: \(self.currentAddress)")
                                            //everything is fine
                                        }
        )

    }


    func convertGPSToAdress(coordinates: CLLocation,
                        completion:  @escaping(String) -> ()) -> () {

    let address = CLGeocoder.init()
    address.reverseGeocodeLocation(coordinates) { (places, error) in
        if error == nil{
            if places != nil {
                let place = places?.first
                completion(formatAddressString(place: place!)) // returns a formatted string address 
            }
        }
    }
}

    ....
}
4

1 回答 1

3

尝试以下（代码快照不可测试 - 所以只是沙哑）

struct PickFoto: View {
    @ObservedObject var observeLocation = LocationObserver.shared()!
    @State private var address: String

    init() {
        _address = State<String>(initialValue: LocationObserver.shared()?.currentAddress ?? " ")
    }

    ...

更新：address将私有状态与外部同步

var body: some View {
    ...
    TextView(text: $text, isEditing: $isEditing) 
       .onReceive(observeLocation.$currentAddress) { newAddress in
            self.address = newAddress
       }
    ...
}
于 2020-02-28T13:31:45.073 回答