Ios SwiftUI中带切换的UserDefaults绑定
我正试图找出最好的方法来构建一个绑定到UserDefaults的简单设置屏幕 基本上,我有一个开关,我想要:Ios SwiftUI中带切换的UserDefaults绑定,ios,swiftui,combine,Ios,Swiftui,Combine,我正试图找出最好的方法来构建一个绑定到UserDefaults的简单设置屏幕 基本上,我有一个开关,我想要: 更改此切换时要保存的UserDefault值(UserDefault应为真实值的来源) 切换始终显示UserDefault的值 我已经观看了许多SwiftuiWWDC会议,但我仍然不确定应该如何使用Combine和SwiftUI中提供的不同工具设置所有内容。我目前的想法是,我应该使用BindableObject,这样我就可以使用hat来封装许多不同的设置 我认为我很接近,因为它几乎
- 更改此切换时要保存的UserDefault值(UserDefault应为真实值的来源)
- 切换始终显示UserDefault的值
import SwiftUI
import Combine
struct ContentView : View {
@ObjectBinding var settingsStore = SettingsStore()
var body: some View {
NavigationView {
Form {
Toggle(isOn: $settingsStore.settingActivated) {
Text("Setting Activated")
}
}
}.navigationBarTitle(Text("Settings"))
}
}
class SettingsStore: BindableObject {
var didChange = NotificationCenter.default.publisher(for: .settingsUpdated).receive(on: RunLoop.main)
var settingActivated: Bool {
get {
UserDefaults.settingActivated
}
set {
UserDefaults.settingActivated = newValue
}
}
}
extension UserDefaults {
private static var defaults: UserDefaults? {
return UserDefaults.standard
}
private struct Keys {
static let settingActivated = "SettingActivated"
}
static var settingActivated: Bool {
get {
return defaults?.value(forKey: Keys.settingActivated) as? Bool ?? false
}
set {
defaults?.setValue(newValue, forKey: Keys.settingActivated)
}
}
}
extension Notification.Name {
public static let settingsUpdated = Notification.Name("SettingsUpdated")
}
我看到的一个问题是,您使用了错误的API从
UserDefaults
设置/获取值。你应使用:
static var settingActivated: Bool {
get {
defaults?.bool(forKey: Keys.settingActivated) ?? false
}
set {
defaults?.set(newValue, forKey: Keys.settingActivated)
}
}
试试这样的。您也可以考虑使用<代码>环境对象< /代码>而不是<代码> ObjultBoope<代码>p>
下面是我经过一些实验后得出的结论,使用
PassthroughSubject
,而不是尝试使用通知。它似乎始终如一地工作,并如预期的那样
我猜可能有一些快速或快捷的技术可以使这更简单,所以请指出如何做类似的事情的其他想法
import SwiftUI
import Combine
struct ContentView : View {
@ObjectBinding var settingsStore: SettingsStore
var body: some View {
NavigationView {
Form {
Toggle(isOn: $settingsStore.settingActivated) {
Text("Setting Activated")
}
}.navigationBarTitle(Text("Settings"))
}
}
}
class SettingsStore: BindableObject {
let didChange = PassthroughSubject<Void, Never>()
var settingActivated: Bool = UserDefaults.settingActivated {
didSet {
UserDefaults.settingActivated = settingActivated
didChange.send()
}
}
}
extension UserDefaults {
private struct Keys {
static let settingActivated = "SettingActivated"
}
static var settingActivated: Bool {
get {
return UserDefaults.standard.bool(forKey: Keys.settingActivated)
}
set {
UserDefaults.standard.set(newValue, forKey: Keys.settingActivated)
}
}
}
导入快捷界面
进口联合收割机
结构ContentView:View{
@ObjectBinding变量settingsStore:settingsStore
var body:一些观点{
导航视图{
形式{
切换(isOn:$settingsStore.settingActivated){
文本(“设置激活”)
}
}.navigationBarTitle(文本(“设置”))
}
}
}
类设置存储:BindableObject{
让didChange=PassthroughSubject()
var settingActivated:Bool=UserDefaults.settingActivated{
迪塞特{
UserDefaults.settingActivated=settingActivated
didChange.send()
}
}
}
扩展用户默认值{
私有结构密钥{
静态let settingActivated=“settingActivated”
}
静态var设置激活:布尔{
得到{
返回UserDefaults.standard.bool(forKey:Keys.settingActivated)
}
设置{
UserDefaults.standard.set(newValue,forKey:Keys.settingActivated)
}
}
}
更新
----iOS 14:----
从iOS 14开始,现在有了一种非常简单的方法来读取和写入UserDefaults
使用名为@AppStorage
以下是如何使用它:
import SwiftUI
struct ContentView : View {
@AppStorage("settingActivated") var settingActivated = false
var body: some View {
NavigationView {
Form {
Toggle(isOn: $settingActivated) {
Text("Setting Activated")
}
}.navigationBarTitle(Text("Settings"))
}
}
}
就这样!这很简单,而且非常直接。您的所有信息都将保存并从UserDefaults读取
-----------iOS 13:-----------
Swift 5.1中发生了很多变化BindableObject
已被完全弃用。此外,PassthroughSubject
也发生了重大变化
对于任何想让它工作的人来说,下面是同样的工作示例。我重复使用了“gohnjanotis”的代码,使它变得简单
import SwiftUI
import Combine
struct ContentView : View {
@ObservedObject var settingsStore: SettingsStore
var body: some View {
NavigationView {
Form {
Toggle(isOn: $settingsStore.settingActivated) {
Text("Setting Activated")
}
}.navigationBarTitle(Text("Settings"))
}
}
}
class SettingsStore: ObservableObject {
let willChange = PassthroughSubject<Void, Never>()
var settingActivated: Bool = UserDefaults.settingActivated {
willSet {
UserDefaults.settingActivated = newValue
willChange.send()
}
}
}
extension UserDefaults {
private struct Keys {
static let settingActivated = "SettingActivated"
}
static var settingActivated: Bool {
get {
return UserDefaults.standard.bool(forKey: Keys.settingActivated)
}
set {
UserDefaults.standard.set(newValue, forKey: Keys.settingActivated)
}
}
}
导入快捷界面
进口联合收割机
结构ContentView:View{
@观察对象变量设置存储:设置存储
var body:一些观点{
导航视图{
形式{
切换(isOn:$settingsStore.settingActivated){
文本(“设置激活”)
}
}.navigationBarTitle(文本(“设置”))
}
}
}
类设置存储:ObservableObject{
let willChange=PassthroughSubject()
var settingActivated:Bool=UserDefaults.settingActivated{
意志{
UserDefaults.settingActivated=newValue
willChange.send()
}
}
}
扩展用户默认值{
私有结构密钥{
静态let settingActivated=“settingActivated”
}
静态var设置激活:布尔{
得到{
返回UserDefaults.standard.bool(forKey:Keys.settingActivated)
}
设置{
UserDefaults.standard.set(newValue,forKey:Keys.settingActivated)
}
}
}
要使此接缝工作良好:
enum BackupLocalisations: String, CaseIterable, Hashable, Identifiable {
case iPhone = "iPhone"
case iCloud = "iCloud"
var name: String {
return self.rawValue
}
var id: BackupLocalisations {self}
}
enum Keys {
static let iCloudIsOn = "iCloudIsOn"
static let backupLocalisation = "backupLocalisation"
static let backupsNumber = "backupsNumber"
}
Xcode 11.3.1在和的帮助下,我已经能够生成一个绑定到UserDefaults的切换,并立即显示您分配给它的任何更改
- 场景代理:
var settingsStore = SettingsStore()
并修改window.rootViewController以显示此信息
window.rootViewController = UIHostingController(rootView: contentView.environmentObject(settingsStore))
- 设置存储:
- 设置存储菜单
import SwiftUI
struct SettingsStoreMenu: View {
@ObservedObject var settingsStore: SettingsStore
var body: some View {
Toggle(isOn: self.$settingsStore.isOn) {
Text("")
}
}
}
- 最后但并非最不重要
import SwiftUI
struct MainView: View {
@EnvironmentObject var settingsStore: SettingsStore
@State var showingSettingsStoreMenu: Bool = false
var body: some View {
HStack {
Button("Go to Settings Store Menu") {
self.showingSettingsStoreMenu.toggle()
}
.sheet(isPresented: self.$showingSettingsStoreMenu) {
SettingsStoreMenu(settingsStore: self.settingsStore)
}
}
}
}
(或您希望的任何其他方式。)您可以扩展
@Published
属性包装,以将值存储在用户默认值中(如中所建议):
下面是基于发布的问题的示例:
import SwiftUI
import Combine
struct ContentView : View {
@ObservedObject var settingsStore = SettingsStore()
var body: some View {
NavigationView {
Form {
Toggle(isOn: $settingsStore.settingActivated) {
Text("Setting Activated")
}
}.navigationBarTitle(Text("Settings"))
}
}
}
class SettingsStore: ObservableObject {
@Published(defaultValue: false, key: "SettingActivated")
var settingActivated: Bool
}
@gohnjanotis的可能复制品刚刚注意到,myBoolSetting
的持久性也可能与这种方法不一致。很抱歉。有时它是有效的。有时候不是。正如你所说;)我使用模拟器进行测试,因为我没有iOS 13设备。有你
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView().environmentObject(Settings())
}
}
var settingsStore = SettingsStore()
window.rootViewController = UIHostingController(rootView: contentView.environmentObject(settingsStore))
import Foundation
class SettingsStore: ObservableObject {
@Published var isOn: Bool = UserDefaults.standard.bool(forKey: "isOn") {
didSet {
UserDefaults.standard.set(self.isOn, forKey: "isOn")
}
}
}
import SwiftUI
struct SettingsStoreMenu: View {
@ObservedObject var settingsStore: SettingsStore
var body: some View {
Toggle(isOn: self.$settingsStore.isOn) {
Text("")
}
}
}
import SwiftUI
struct MainView: View {
@EnvironmentObject var settingsStore: SettingsStore
@State var showingSettingsStoreMenu: Bool = false
var body: some View {
HStack {
Button("Go to Settings Store Menu") {
self.showingSettingsStoreMenu.toggle()
}
.sheet(isPresented: self.$showingSettingsStoreMenu) {
SettingsStoreMenu(settingsStore: self.settingsStore)
}
}
}
}
private var cancellables = [String: AnyCancellable]()
extension Published {
init(defaultValue: Value, key: String) {
let value = UserDefaults.standard.object(forKey: key) as? Value ?? defaultValue
self.init(initialValue: value)
cancellables[key] = projectedValue.sink { val in
UserDefaults.standard.set(val, forKey: key)
}
}
}
import SwiftUI
import Combine
struct ContentView : View {
@ObservedObject var settingsStore = SettingsStore()
var body: some View {
NavigationView {
Form {
Toggle(isOn: $settingsStore.settingActivated) {
Text("Setting Activated")
}
}.navigationBarTitle(Text("Settings"))
}
}
}
class SettingsStore: ObservableObject {
@Published(defaultValue: false, key: "SettingActivated")
var settingActivated: Bool
}