Simple assignment operation in init method does not work swiftui

Question

I am new in iOS and, right now, trying to implement my own init method in swiftui view. Init has one parameter and have to assign value to two States. But, whatever I do, it does not fill them properly. I use MapKit and CLLocationCoordinate2D for geolocation. Just to add, coordinates: CLLocationCoordinate2D in init has right value, but state has not. The view I am implement here is ModalView Any idea what to do? Here is my code.


    @State var coordinate = CLLocationCoordinate2D()
    @State private var name: String = ""
    @State private var price: Decimal = 0
    @State private var priceStr: String = ""
    @State private var showAlert = false
    @State private var location = ParkPlaceRespons(id: -1, name: "", price: -0, longitude: 18.42645, latitude: 43.85623)
    @State private var mapArray = [ParkPlaceRespons]()

    var alert: Alert{
        Alert(title: Text("Error"), message: Text("Your price input is not in right format"), dismissButton: .default(Text("Ok")))}

    init(coordinates: CLLocationCoordinate2D){
        print(coordinates)    // CLLocationCoordinate2D(latitude: 43.85613, longitude: 18.42745)
        self.coordinate = coordinates
        print(self.coordinate)   // CLLocationCoordinate2D(latitude: 0.0, longitude: 0.0)
        self.coordinate.latitude = coordinates.latitude
        self.coordinate.longitude = coordinates.longitude
        self.location.longitude = coordinates.longitude
        self.location.latitude = coordinates.latitude
        print(location)  // Does not work as well
        self.mapArray.append(location)
        print(mapArray)   // Empty array
    }

score 0 · Answer 1 · answered Dec 18 '19 at 15:18

When you look into documentation about @State you will find this fragment:

Only access a state property from inside the view’s body (or from functions called by it). For this reason, you should declare your state properties as private, to prevent clients of your view from accessing it.

Therefore you should not set the coordinates, location or mapArray in the initializer, if you find that it is necessary to set the varaibles in the initializer you should either declare them as a @Binding or @ObservedObject.

Simple assignment operation in init method does not work swiftui

1 Answers1