Swift 中 @Binding var 的 didSet

使用Swift中的@Binding属性时，我们经常需要在属性值发生改变时执行一些特定的操作。为了实现这一点，我们可以使用属性观察器didSet。在这篇文章中，我们将探讨在Swift中如何使用@Binding var的didSet属性观察器，并提供一些案例代码来帮助我们更好地理解它的用法和作用。

swift
struct ContentView: View {
    @State private var name = "Swift"
    @State private var isNameChanged = false
    var body: some View {
        VStack {
            Text("Hello, \(name)!")
                .padding()
            Button(action: {
                self.name = "SwiftUI"
            }) {
                Text("Change Name")
            }
        }
        .onAppear {
            self.isNameChanged = false
        }
        .onDisappear {
            self.isNameChanged = true
        }
        ChildView(name: $name, isNameChanged: $isNameChanged)
    }
}
struct ChildView: View {
    @Binding var name: String
    @Binding var isNameChanged: Bool
    var body: some View {
        VStack {
            Text("Child View")
                .padding()
            if isNameChanged {
                Text("Name is changed!")
                    .padding()
            }
            Button(action: {
                self.name = "Changed in Child View"
            }) {
                Text("Change Name in Child View")
            }
        }
    }
}