在视图控制器中创建 Publishable 属性，将其传递给 SwiftUI 视图并监听视图控制器内部的更改？

Question

这就是我想要达到的目标：

class MyVC: UIViewController {
    @State var myBoolState: Bool = false

    private var subscribers = Set<AnyCancellable>()

    override func viewDidLoad() {
        super.viewDidLoad()

        myBoolState.sink { value in .... }.store(in:&subscribers)
    }

    func createTheView() {
        let vc = UIHostingController(rootView: MySwiftUIView(myBoolState: $myBoolState))
        self.navigationController!.pushViewController(vc, animated: true)
    }
}

struct MySwiftUIView: View {
    @Binding var myBoolState: Bool

    var body: some View {
          Button(action: {
              myBoolState = true
          }) {
              Text("Push Me")
          }

    }

}

但是上面的当然不能编译。

所以问题是：我能否以某种方式在视图控制器中声明已发布的属性，将其传递给 SwiftUI 视图并在 SwiftUI 视图更改其值时得到通知？

Answer 1

@State 包装器（按设计）仅在 SwiftUI 视图中工作，因此您不能在视图控制器中使用它。取而代之的是 ObsevableObject/ObservedObject 模式，因为它基于引用类型。

这里是您的方案可能解决方案的演示：

import Combine

class ViewModel: ObservableObject {
    @Published var myBoolState: Bool = false
}

class MyVC: UIViewController {
    let vm = ViewModel()
    
    private var subscribers = Set<AnyCancellable>()

    override func viewDidLoad() {
        super.viewDidLoad()

        vm.$myBoolState.sink { value in
            print(">> here it goes")
        }.store(in:&subscribers)
    }

    func createTheView() {
        let vc = UIHostingController(rootView: MySwiftUIView(vm: self.vm))
        self.navigationController!.pushViewController(vc, animated: true)
    }
}

struct MySwiftUIView: View {
    @ObservedObject var vm: ViewModel

    var body: some View {
          Button(action: {
            vm.myBoolState = true
          }) {
              Text("Push Me")
          }
    }
}