SwiftUI -选取器.onChange和didSet

import SwiftUI

struct ContentView: View {
    @State private var selectedOption = "Option 1"
    let options = ["Option 1", "Option 2", "Option 3"]

    var body: some View {
        VStack {
            Picker("Select an option", selection: $selectedOption) {
                ForEach(options, id: \.self) { option in
                    Text(option)
                }
            }
            .pickerStyle(SegmentedPickerStyle())
            .onChange(of: selectedOption) { newValue in
                print("Selected option changed to: \(newValue)")
                // 在这里执行其他操作，例如更新其他 UI 元素或执行网络请求
            }
        }
    }
}

import SwiftUI

class ViewModel: ObservableObject {
    @Published var selectedOption = "Option 1" {
        didSet {
            print("Selected option changed to: \(selectedOption)")
            // 在这里执行其他操作，例如数据验证或触发其他业务逻辑
        }
    }

    let options = ["Option 1", "Option 2", "Option 3"]
}

struct ContentView: View {
    @StateObject private var viewModel = ViewModel()

    var body: some View {
        VStack {
            Picker("Select an option", selection: $viewModel.selectedOption) {
                ForEach(viewModel.options, id: \.self) { option in
                    Text(option)
                }
            }
            .pickerStyle(SegmentedPickerStyle())
        }
    }
}