如何强制创建新UIViewControllerRepresentable？解决视图更新问题

核心问题在于UIViewControllerRepresentable的makeUIViewController仅初始化一次，视图更新需通过updateUIViewController方法同步已创建的视图控制器内容。以下是保持MyView私有前提下的最优修改方案：

修改后的完整代码 #

private struct ControllerView<Content: View>: View {
    struct MyView<ContentM: View>: UIViewControllerRepresentable {
        let rootView: ContentM
        
        init(rootView: ContentM) {
            self.rootView = rootView
            print("init MyView")
        }
        
        func makeUIViewController(context: Context) -> UIViewController {
            print("makeUI")
            /// 创建自定义VC（这里用UIHostingController示例）
            return UIHostingController(rootView: rootView)
        }
        
        func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
            print("updateUI")
            // 将已创建的VC强转为UIHostingController，更新其rootView
            if let hostingVC = uiViewController as? UIHostingController<ContentM> {
                hostingVC.rootView = rootView
            }
        }
    }
    
    let rootView: () -> Content
    @Binding var isGreen: Bool
    
    init(isGreen: Binding<Bool>,@ViewBuilder rootView: @escaping () -> Content) {
        self.rootView = rootView
        self._isGreen = isGreen
    }
    
    var body: some View {
        ZStack {
            MyView(rootView: rootView())
            
            Button {
                isGreen.toggle()
            } label: {
                Text("Change")
            }
        }
    }
}

private struct GreenView: View  {
    var body: some View {Color.green.ignoresSafeArea()}
}
private struct OrangeView: View  {
    var body: some View {Color.orange.ignoresSafeArea()}
}

struct SwiftUIView21: View {
    @State var isGreen: Bool = true
    
    var body: some View {
        ControllerView(isGreen: $isGreen) {
            if isGreen {
                GreenView()
            } else {
                OrangeView()
            }
        }
    }
}

#Preview {
    SwiftUIView21()
}

关键修改点说明 #

1. 在updateUIViewController中同步视图内容：
   当isGreen切换导致rootView变化时，MyView的rootView属性会被更新，触发updateUIViewController方法。此时将已初始化的UIHostingController强转后，直接替换其rootView属性，实现视图更新。
2. 保持原有结构私有性：
   MyView依然嵌套在ControllerView内部保持私有，无需暴露给外部代码。

内容的提问来源于stack exchange，提问作者Amirca