ios - SwiftUI:ViewModifier 不监听 onReceive 事件

Question

我有一个自定义 ViewModifier它只是返回带有 onReceive 的相同内容修饰符，onReceive没有触发，这里有一个示例代码，您可以在XCode中复制、粘贴和运行:

import SwiftUI
import Combine

class MyViewModel: ObservableObject {
    @Published var myProperty: Bool = false
}
struct ContentView: View {
    @ObservedObject var viewModel: MyViewModel

    var body: some View {
        Text("Hello, World!")
        .modifier(MyOnReceive(viewModel: viewModel))
            .onTapGesture {
                self.viewModel.myProperty = true
        }
    }
}

struct MyOnReceive: ViewModifier {
    @ObservedObject var viewModel: MyViewModel

    func body(content: Content) -> some View {
        content
            .onReceive(viewModel.$myProperty) { theValue in
                print("The Value is \(theValue)") // <--- this is not executed
        }
    }
}

是 SwiftUI旨在禁止 onReceive在 ViewModifier 内执行或者它是一个错误？我在现实生活中的项目中有一个 View ，该 View 通过放入一些业务逻辑而变得更大 onReceive ，所以我需要通过将其与 onReceive 分开来清理该 View .

Answer 1

好的，这对我有用:

func body(content: Content) -> some View {
    content
        .onAppear()   // <--- this makes it work
        .onReceive(viewModel.$myProperty) { theValue in
            print("-----> The Value is \(theValue)") // <--- this will be executed
    }
}