如何在 swiftUI 中删除 Observer？

Question

我有一个视图，在其中添加观察者onAppear并在onDisappear方法中删除该观察者。但观察者并没有被移除。我阅读了文档但没有找到任何解决方案。寻求帮助。谢谢

struct MainListView: View {

       let NC = NotificationCenter.default
       var body: some View {
       VStack(alignment: .center, spacing: 1) {
         .......
       }
       .onDisappear{
            self.NC.removeObserver(self, name: Notification.Name(rawValue: "redrawCategories"), object: self)
        }
       .onAppear {
            self.NC.addObserver(forName: Notification.Name(rawValue: "redrawCategories"), object: nil, queue: nil) { (notification) in
                .......
            }
        }
    }
}

Answer 1

这是观察通知的 SwiftUI 方法

struct MainListView: View {

    let redrawCategoriesPublisher = NotificationCenter.default.publisher(for: 
          Notification.Name(rawValue: "redrawCategories"))

    var body: some View {
        VStack(alignment: .center, spacing: 1) {
            Text("Demo")
        }
        .onReceive(redrawCategoriesPublisher) { notification in
            // do here what is needed
        }
    }
}