一个 ObservedObject 需要接受另一个 ObservedObject 作为参数；你怎么做到这一点？

Question

struct ContentView {
    @ObservedObject var annotationsVM = AnnotationsVM()
    //I'd like to pass in the ViewModel() declared below into annotationsVM like AnnotationsVM(VModel: Vmodel)
    @ObservedObjects var VModel = ViewModel()

    var body: some View {
        //All the SwiftUI view setup is in here
    }
}

class AnnotationsVM: ObservableObject {
    @ObservedObject var VModel = ViewModel()
    //I'd like to pass in the VModel in content view like: @ObservedObject var VModel: VModel
}

显然，我不能像我想要的那样在创建 ContentView 时直接传入 VModel，因为尚未创建 VModel 对象，所以它无法访问...

Recap：我想将在 ContentView 中声明的 VModel 实例传入 annotationsVM 实例（也在 ContentView 中声明）

Answer 1

您可以在init 中这样做：

struct ContentView {
    @ObservedObject var annotationsVM: AnnotationsVM
    @ObservedObject var vModel: ViewModel

    init() {
        let vm = ViewModel()
        vModel = vm
        annotationsVM = AnnotationsVM(vModel: vm)
    }

    var body: some View {
        //All the SwiftUI view setup is in here
    }
}

class AnnotationsVM: ObservableObject {
    var vModel: ViewModel

    init(vModel: ViewModel) {
        vModel = vModel
    }
}

您只能在View 中使用@ObservedObject。

注意：最好在 init 中将 ViewModels 作为参数传递以遵循Dependency Injection 模式。