SwiftUI:如何使用 UserDefaults 保存选择器数据？

Question

我是 SwiftUI 的新手，想从选择器中保存用户选择。我知道我需要 用户默认值 为此，但我不知道如何使用 用户默认值 在这种情况下。

struct ContentView: View {

    @Environment(\.colorScheme) var colorScheme
    @State var PickerSelection = 0
    
    //PickerStyle

    init() {
        UISegmentedControl.appearance().selectedSegmentTintColor = .init(UIColor(named: "Color_Picker")!)
        UISegmentedControl.appearance().setTitleTextAttributes([.foregroundColor: UIColor.white], for: .selected)
        UISegmentedControl.appearance().setTitleTextAttributes([.foregroundColor: UIColor.init(named: "Color_Picker")!], for: .normal)
    }
    
    var body: some View {
        VStack {
            Picker("", selection: $PickerSelection) {
            Text("Selection 1").tag(0)
            Text("Selection 2").tag(1)
            } .pickerStyle(SegmentedPickerStyle()).padding(.horizontal, 100)
            Text("Hello World!")
    }
}

Answer 1

您可以使用 .onReceive在 Just 的帮助下发布者(与 iOS 13* 兼容)

import Combine
struct ContentView: View {

    @Environment(\.colorScheme) var colorScheme
    @State var PickerSelection = UserDefaults.standard.integer(forKey: "Picker")

    //PickerStyle

    init() {
        UISegmentedControl.appearance().selectedSegmentTintColor = .init(UIColor(named: "Color_Picker")!)
        UISegmentedControl.appearance().setTitleTextAttributes([.foregroundColor: UIColor.white], for: .selected)
        UISegmentedControl.appearance().setTitleTextAttributes([.foregroundColor: UIColor.init(named: "Color_Picker")!], for: .normal)
    }

    var body: some View {
        VStack {
            Picker("", selection: $PickerSelection) {
                Text("Selection 1").tag(0)
                Text("Selection 2").tag(1)
            }
            .pickerStyle(SegmentedPickerStyle()).padding(.horizontal, 100)
            .onReceive(Just(PickerSelection)) {
                UserDefaults.standard.set($0, forKey: "Picker")   // << here !!
            }

            Text("Hello World!")
        }
    }
}