在 SwiftUI 中，如何为已发布视图更改设置动画？

Question

I would like to animate a View change.
In particular, I have done a View where one of its children is a changing View.

struct MasterView: View {

    @State var playerLeft: Bool = false
    @ObservedObject var viewModel: MasterViewModel

    var body: some View {
        ZStack {
            WaitPlayerBackView(isShowing: self.$playerLeft) {
                self.viewModel.currentView
            }
        }
    }
}

The view model is an ObservableObject class. currentView is changed by a method called from an async thread, like this:

class MasterViewModel: ObservableObject {
    @Published var currentView: AnyView = AnyView(EmptyView())

    func changeView() {
        self.currentView = AnyView(NightView())
    }
}

It's like a copy of Android fragments (pardon the comparison).
How can I animate this View change?
I have tried different options like:

self.viewModel.currentView.animate(.default)

or

struct MasterView: View {

    @State var playerLeft: Bool = false
    @ObservedObject var viewModel: MasterViewModel

    var body: some View {
        ZStack {
            WaitPlayerBackView(isShowing: self.$playerLeft) {
                self.viewModel.currentView
            }
        }.animate(self.viewModel.animate ? .easeIn(duration: 1) : .none)
    }
}

class MasterViewModel: ObservableObject {
    @Published var currentView: AnyView = AnyView(EmptyView())
    @Published var animate = false

    func changeView() {
        self.animate = false
        self.currentView = AnyView(NightView())
        self.animate = true
    }
}

However, none of them worked.
This is how I see a transition when changing the instance of currentView.

Answer 1

Moving your view initialization to MasterView makes everything easier:

struct MasterView: View {

    @State var playerLeft: Bool = false
    @ObservedObject var viewModel: MasterViewModel

    var body: some View {
        ZStack {
            VStack { //this represents WaitPlayerBackView
                if viewModel.day { //here are the posibles views that self.viewModel.currentView could have
                    Text("DayView").transition(AnyTransition.opacity.animation(.easeInOut(duration: 1.0)))
                } else {
                    Text("NightView").transition(AnyTransition.opacity.animation(.(duration: 1.0)))
                }
            }
        }
    }
}

class MasterViewModel: ObservableObject {
    @Published var day: Bool = false

    init () {
        _ = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(changeView), userInfo: nil, repeats: true) //Only for testing
    }
    @objc func changeView() { //@objc is only for testing
        day.toggle()
    }
}