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Accepted
Fabian Reyes
Asked: 2021-12-01 06:48:32 +0800 CST 2021-12-01 06:48:32 +0800 CST

Variable in SwiftUI Initializer

  • 772

I have the following code:

    import SwiftUI
    import QGrid
    
    struct VerCanales: View {
        
        var categoria:String
        @ObservedObject var canales = CargarCanales(categoriaID: categoria)
        
        var body: some View {
            NavigationView{
                QGrid(self.canales.listaCanales, columns: 3){item in
                    NavigationLink(destination:VlcPlayerDemo()){
                        Text(item.name).frame(width:400, height:50)
                    }
                }
                
            }.navigationBarTitle(Text("CHANNELS AVAILABLE"))
        }
    }

The variable "category" comes from the above view as a parameter and I need to pass it as a parameter to the @ObservedObject but I get the following error: "Cannot use instance member 'category' within property initializer; property initializers run before 'self' is available"

I guess you mean that I can't use the variable since it hasn't been initialized.

I am new to the language and have searched but can't find a good solution

swift

2 Answers

  1. Best Answer

    I have solved it in a simpler way in this way:

    struct VerCanales: View {
    
    private var categoria: String
    @ObservedObject private var canales: CargarCanales
    
    init(categoria: String) {
        self.categoria = categoria
        self.canales = CargarCanales(categoriaID: categoria)
    }
    
    var body: some View {
        NavigationView{
            QGrid(self.canales.listaCanales, columns: 3){item in
                NavigationLink(destination:VlcPlayerDemo()){
                    Text(item.name).frame(width:400, height:50)
                }
            }
            
        }.navigationBarTitle(Text("CHANNELS AVAILABLE"))
    }
}
    • 1

  2. When working with @ObservedObjectyou need to initialize the actual value of the object before using.

    In your class just the initlike this:

    class CargarCanales: ObservableObject {
    var categoriaID: String

    init() {
        self.categoriaId = ""
    }
}

    You have to initialize the object in the view and save the object for use:

    struct VerCanales: View {
        
    var categoria: String
    @ObservedObject var canales: CargarCanales = CargarCanales()

    init(categoria: String, canales = CargarCanales()) {
        self._canales = ObservedObject(wrappedValue: canales)//Almacenamos el objeto de tipo ObservedObject
        self._canales.wrappedValue.categoriaId = categoria//Asignamos el valor de categoría al objeto almacenado
        self.categoria = categoria
    }
        
    var body: some View {
        Text(canales.categoriaId)//Imprime Test        
    }
}

struct ContetnView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView(categoria: "Test")
    }
}
    • 0