在 SwiftUI 中使用可观察对象切换视图 [英] Switching Views With Observable Objects in SwiftUI

问题描述

我正在练习尝试使用 SwiftUI 中的可观察对象切换视图，但我的代码不起作用.我知道我可以用@State 做到这一点，但我想让它与可观察对象一起工作.当我在内容视图中单击图像时，图像不会改变.有人可以帮我吗?

I am practicing trying to switch views using observable objects in SwiftUI, but my code isn't working. I know I can do this with @State, but I would like to get this working with observable objects. When I click on the image in the content view, the image doesn't change. Can someone help me?

ContentView.swift

import SwiftUI

struct ContentView: View {

    @ObservedObject var viewRouter: ViewRouter


    var body: some View {

        VStack {

            Button(action: {self.viewRouter.currentPage = "Page2"}) {
                Image(viewRouter.currentPage)
            }

            if viewRouter.currentPage == "Page1" {
                Page1(viewRouter: viewRouter)

            }else if viewRouter.currentPage == "Page2" {
                Page2(viewRouter: viewRouter)
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView(viewRouter: ViewRouter())
    }
  }

ViewRouter.swift

import Foundation
import SwiftUI
import Combine

class ViewRouter: ObservableObject {

    let objectWillChange = PassthroughSubject<ViewRouter, Never>()

   @Published var currentPage: String = "Page1"

  }

Page1.swift

import SwiftUI

struct Page1: View {

    @ObservedObject var viewRouter:ViewRouter

    var body: some View {
        VStack {
         Image("ET-LondonBridge")
        }
    }
}

struct Page1_Previews: PreviewProvider {
    static var previews: some View {
        Page1(viewRouter: ViewRouter())
    }
}

Page2.swift

import SwiftUI

struct Page2: View {

    @ObservedObject var viewRouter:ViewRouter

    var body: some View {
        VStack {
            Image("BigBen")
                .aspectRatio(contentMode: .fit)
        }
    }
}

struct Page2_Previews: PreviewProvider {
    static var previews: some View {
        Page2(viewRouter: ViewRouter())
    }
}

推荐答案

你不需要这条线就可以让所有事情正常进行.只需注释掉这一行

You don't need this line to make all things work. Just comment out this line

//let objectWillChange = PassthroughSubject<ViewRouter, Never>()

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