State 未更新到 swiftUI 中的另一个视图

Question

我正在使用它来将用户信息保存在用户 isRegsitered 的用户默认值中。

struct UserKeys {
    static let isUserRegistered = "isUserRegistered"
}
@propertyWrapper
struct UserDefault<T> {
    let key: String
    let defaultValue: T
    
    init(_ key: String, defaultValue: T) {
        self.key = key
        self.defaultValue = defaultValue
    }
    
    var wrappedValue: T {
        get {
            return UserDefaults.standard.object(forKey: key) as? T ?? defaultValue
        }
        set {
            UserDefaults.standard.set(newValue, forKey: key)
        }
    }
}
final class UserSettings: ObservableObject {

    let objectWillChange = PassthroughSubject<Void, Never>()

    @UserDefault(UserKeys.isUserRegistered, defaultValue: false)
    var isUserRegistered: Bool {
        willSet {
            objectWillChange.send()
        }
    }
}

// 同一仪表板视图上的弹出登录 window。

struct PopUpWindow: View {
    @ObservedObject var userRepo = UserSettings()
 Button(action: {
                            // Dismiss the PopUp
                            withAnimation(.linear(duration: 0.3)) {
                                userRepo.isUserRegistered = true
                                show = false
                                hideKeyboard()
                            }
                        }, label: {
                            Text("Submit")

& 此外，我在 DashBoardView 视图中列出 -

struct DashBoardView: View {

    @ObservedObject var userRepo = UserSettings()

    private var content: some View {
        if !userRepo.isUserRegistered {
            return PopUpWindow(show: .constant(true)) .eraseToAnyView()
        }
// .. Other conditions .. 

所以基本上我弹出了登录框，所以在提交后我试图关闭对话框并想听值userRepo.isUserRegistered

Answer 1

通过在PopUpWindow和DashBoardView中独立初始化UserSettings class ，您实际上是在说每个视图都在管理自己的数据，因此两个视图不共享相同的数据。

您不应该从PopUpWindow视图初始化您的UserSettings class ，而是从DashBoardView传递一个实例。 代码如下所示：

弹出窗口

struct PopUpWindow: View {
    @ObservedObject var userRepo: UserSettings
    Button(action: {
           // Dismiss the PopUp
           withAnimation(.linear(duration: 0.3)) {
           userRepo.isUserRegistered = true
           show = false
           hideKeyboard()
           }
           }, label: {
           Text("Submit")
// .. Other conditions .. 

接着：

仪表板视图

struct DashBoardView: View {
    
    @ObservedObject var userRepo = UserSettings()
    
    private var content: some View {
        if !userRepo.isUserRegistered {
            return PopUpWindow(userRepo: userRepo, show: .constant(true)) .eraseToAnyView()
        }
// .. Other conditions ..