SwiftUI ViewModel 永远保持 init

Question

我有这样的结构。

import SwiftUI

//create a simple view model
class ViewModel: NSObject, ObservableObject {
    @Published var name: String = "World"
    //create a reference of another viewmodel
    let anotherViewModel = AnotherViewModel()
    override init() {
        super.init()
        print("init")
        Settings.shared.test = "2"
    }
}

//create another view model
class AnotherViewModel: ObservableObject {
    @Published var name: String = "World"
    init(){
        print("another init")
        Settings.shared.test = "3"
    }
}

//create singleton with a bool
class Settings: ObservableObject {
    static let shared = Settings()
    @Published var isShow: Bool = false
    @Published var test = "1"
}

struct FatherView: View {
    @StateObject var settings = Settings.shared//if I remove this line, it will be normal.
    var body:some View{
        ContentView()
    }
}

struct ContentView: View {
    //@StateObject var settingsHolder = Settings.shared
    @StateObject var model: ViewModel
    @StateObject var model1: AnotherViewModel
    init() {
        let model = ViewModel()
        _model = StateObject(wrappedValue: model)
        _model1 = StateObject(wrappedValue: model.anotherViewModel)
    }
    var body: some View {
        VStack {
            Text("Hi")
        }
    }
}

一旦我更改了设置参数的值，两个视图模型将永远重复初始化，并且似乎只有当我将

ContentView

放入

FatherView

并在

中声明设置的@StateObject时才会发生这种情况

Answer 1

这似乎是正确的，因为当您初始化

ViewModel

和

AnotherViewModel

时，您还设置了

Settings.shared

值，该值绑定到

FatherView

。这是循环的原因。

FatherView -> get ContentView -> init ViewModel -> Setting.shared -> get Content -> Loop...